1. 22 Sep, 2022 21 commits
    • Lorenzo Bianconi's avatar
      net: netfilter: add bpf_ct_set_nat_info kfunc helper · 0fabd2aa
      Lorenzo Bianconi authored
      Introduce bpf_ct_set_nat_info kfunc helper in order to set source and
      destination nat addresses/ports in a new allocated ct entry not inserted
      in the connection tracking table yet.
      Signed-off-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
      Link: https://lore.kernel.org/r/9567db2fdfa5bebe7b7cc5870f7a34549418b4fc.1663778601.git.lorenzo@kernel.orgSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      0fabd2aa
    • Kumar Kartikeya Dwivedi's avatar
      bpf: Tweak definition of KF_TRUSTED_ARGS · eed807f6
      Kumar Kartikeya Dwivedi authored
      Instead of forcing all arguments to be referenced pointers with non-zero
      reg->ref_obj_id, tweak the definition of KF_TRUSTED_ARGS to mean that
      only PTR_TO_BTF_ID (and socket types translated to PTR_TO_BTF_ID) have
      that constraint, and require their offset to be set to 0.
      
      The rest of pointer types are also accomodated in this definition of
      trusted pointers, but with more relaxed rules regarding offsets.
      
      The inherent meaning of setting this flag is that all kfunc pointer
      arguments have a guranteed lifetime, and kernel object pointers
      (PTR_TO_BTF_ID, PTR_TO_CTX) are passed in their unmodified form (with
      offset 0). In general, this is not true for PTR_TO_BTF_ID as it can be
      obtained using pointer walks.
      Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Signed-off-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
      Link: https://lore.kernel.org/r/cdede0043c47ed7a357f0a915d16f9ce06a1d589.1663778601.git.lorenzo@kernel.orgSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      eed807f6
    • Hou Tao's avatar
      bpf: Always use raw spinlock for hash bucket lock · 1d8b82c6
      Hou Tao authored
      For a non-preallocated hash map on RT kernel, regular spinlock instead
      of raw spinlock is used for bucket lock. The reason is that on RT kernel
      memory allocation is forbidden under atomic context and regular spinlock
      is sleepable under RT.
      
      Now hash map has been fully converted to use bpf_map_alloc, and there
      will be no synchronous memory allocation for non-preallocated hash map,
      so it is safe to always use raw spinlock for bucket lock on RT. So
      removing the usage of htab_use_raw_lock() and updating the comments
      accordingly.
      Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
      Link: https://lore.kernel.org/r/20220921073826.2365800-1-houtao@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      1d8b82c6
    • Jiri Olsa's avatar
      bpf: Prevent bpf program recursion for raw tracepoint probes · 05b24ff9
      Jiri Olsa authored
      We got report from sysbot [1] about warnings that were caused by
      bpf program attached to contention_begin raw tracepoint triggering
      the same tracepoint by using bpf_trace_printk helper that takes
      trace_printk_lock lock.
      
       Call Trace:
        <TASK>
        ? trace_event_raw_event_bpf_trace_printk+0x5f/0x90
        bpf_trace_printk+0x2b/0xe0
        bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
        bpf_trace_run2+0x26/0x90
        native_queued_spin_lock_slowpath+0x1c6/0x2b0
        _raw_spin_lock_irqsave+0x44/0x50
        bpf_trace_printk+0x3f/0xe0
        bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
        bpf_trace_run2+0x26/0x90
        native_queued_spin_lock_slowpath+0x1c6/0x2b0
        _raw_spin_lock_irqsave+0x44/0x50
        bpf_trace_printk+0x3f/0xe0
        bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
        bpf_trace_run2+0x26/0x90
        native_queued_spin_lock_slowpath+0x1c6/0x2b0
        _raw_spin_lock_irqsave+0x44/0x50
        bpf_trace_printk+0x3f/0xe0
        bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
        bpf_trace_run2+0x26/0x90
        native_queued_spin_lock_slowpath+0x1c6/0x2b0
        _raw_spin_lock_irqsave+0x44/0x50
        __unfreeze_partials+0x5b/0x160
        ...
      
      The can be reproduced by attaching bpf program as raw tracepoint on
      contention_begin tracepoint. The bpf prog calls bpf_trace_printk
      helper. Then by running perf bench the spin lock code is forced to
      take slow path and call contention_begin tracepoint.
      
      Fixing this by skipping execution of the bpf program if it's
      already running, Using bpf prog 'active' field, which is being
      currently used by trampoline programs for the same reason.
      
      Moving bpf_prog_inc_misses_counter to syscall.c because
      trampoline.c is compiled in just for CONFIG_BPF_JIT option.
      Reviewed-by: default avatarStanislav Fomichev <sdf@google.com>
      Reported-by: syzbot+2251879aa068ad9c960d@syzkaller.appspotmail.com
      [1] https://lore.kernel.org/bpf/YxhFe3EwqchC%2FfYf@krava/T/#tSigned-off-by: default avatarJiri Olsa <jolsa@kernel.org>
      Link: https://lore.kernel.org/r/20220916071914.7156-1-jolsa@kernel.orgSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      05b24ff9
    • Alexei Starovoitov's avatar
      Merge branch 'bpf: Add kfuncs for PKCS#7 signature verification' · 66d6a4bf
      Alexei Starovoitov authored
      Roberto Sassu says:
      
      ====================
      One of the desirable features in security is the ability to restrict import
      of data to a given system based on data authenticity. If data import can be
      restricted, it would be possible to enforce a system-wide policy based on
      the signing keys the system owner trusts.
      
      This feature is widely used in the kernel. For example, if the restriction
      is enabled, kernel modules can be plugged in only if they are signed with a
      key whose public part is in the primary or secondary keyring.
      
      For eBPF, it can be useful as well. For example, it might be useful to
      authenticate data an eBPF program makes security decisions on.
      
      After a discussion in the eBPF mailing list, it was decided that the stated
      goal should be accomplished by introducing four new kfuncs:
      bpf_lookup_user_key() and bpf_lookup_system_key(), for retrieving a keyring
      with keys trusted for signature verification, respectively from its serial
      and from a pre-determined ID; bpf_key_put(), to release the reference
      obtained with the former two kfuncs, bpf_verify_pkcs7_signature(), for
      verifying PKCS#7 signatures.
      
      Other than the key serial, bpf_lookup_user_key() also accepts key lookup
      flags, that influence the behavior of the lookup. bpf_lookup_system_key()
      accepts pre-determined IDs defined in include/linux/verification.h.
      
      bpf_key_put() accepts the new bpf_key structure, introduced to tell whether
      the other structure member, a key pointer, is valid or not. The reason is
      that verify_pkcs7_signature() also accepts invalid pointers, set with the
      pre-determined ID, to select a system-defined keyring. key_put() must be
      called only for valid key pointers.
      
      Since the two key lookup functions allocate memory and one increments a key
      reference count, they must be used in conjunction with bpf_key_put(). The
      latter must be called only if the lookup functions returned a non-NULL
      pointer. The verifier denies the execution of eBPF programs that don't
      respect this rule.
      
      The two key lookup functions should be used in alternative, depending on
      the use case. While bpf_lookup_user_key() provides great flexibility, it
      seems suboptimal in terms of security guarantees, as even if the eBPF
      program is assumed to be trusted, the serial used to obtain the key pointer
      might come from untrusted user space not choosing one that the system
      administrator approves to enforce a mandatory policy.
      
      bpf_lookup_system_key() instead provides much stronger guarantees,
      especially if the pre-determined ID is not passed by user space but is
      hardcoded in the eBPF program, and that program is signed. In this case,
      bpf_verify_pkcs7_signature() will always perform signature verification
      with a key that the system administrator approves, i.e. the primary,
      secondary or platform keyring.
      
      Nevertheless, key permission checks need to be done accurately. Since
      bpf_lookup_user_key() cannot determine how a key will be used by other
      kfuncs, it has to defer the permission check to the actual kfunc using the
      key. It does it by calling lookup_user_key() with KEY_DEFER_PERM_CHECK as
      needed permission. Later, bpf_verify_pkcs7_signature(), if called,
      completes the permission check by calling key_validate(). It does not need
      to call key_task_permission() with permission KEY_NEED_SEARCH, as it is
      already done elsewhere by the key subsystem. Future kfuncs using the
      bpf_key structure need to implement the proper checks as well.
      
      Finally, the last kfunc, bpf_verify_pkcs7_signature(), accepts the data and
      signature to verify as eBPF dynamic pointers, to minimize the number of
      kfunc parameters, and the keyring with keys for signature verification as a
      bpf_key structure, returned by one of the two key lookup functions.
      
      bpf_lookup_user_key() and bpf_verify_pkcs7_signature() can be called only
      from sleepable programs, because of memory allocation and crypto
      operations. For example, the lsm.s/bpf attach point is suitable,
      fexit/array_map_update_elem is not.
      
      The correctness of implementation of the new kfuncs and of their usage is
      checked with the introduced tests.
      
      The patch set includes a patch from another author (dependency) for sake of
      completeness. It is organized as follows.
      
      Patch 1 from KP Singh allows kfuncs to be used by LSM programs. Patch 2
      exports the bpf_dynptr definition through BTF. Patch 3 splits
      is_dynptr_reg_valid_init() and introduces is_dynptr_type_expected(), to
      know more precisely the cause of a negative result of a dynamic pointer
      check. Patch 4 allows dynamic pointers to be used as kfunc parameters.
      Patch 5 exports bpf_dynptr_get_size(), to obtain the real size of data
      carried by a dynamic pointer. Patch 6 makes available for new eBPF kfuncs
      and programs some key-related definitions. Patch 7 introduces the
      bpf_lookup_*_key() and bpf_key_put() kfuncs. Patch 8 introduces the
      bpf_verify_pkcs7_signature() kfunc. Patch 9 changes the testing kernel
      configuration to compile everything as built-in. Finally, patches 10-13
      introduce the tests.
      
      Changelog
      
      v17:
       - Remove unnecessary typedefs in test_verify_pkcs7_sig.c (suggested by KP)
       - Add patch to export bpf_dynptr through BTF (reported by KP)
       - Rename u{8,16,32,64} variables to __u{8,16,32,64} in the tests, for
         consistency with other eBPF programs (suggested by Yonghong)
      
      v16:
       - Remove comments in include/linux/key.h for KEY_LOOKUP_*
       - Change kmalloc() flag from GFP_ATOMIC to GFP_KERNEL in
         bpf_lookup_user_key(), as the kfunc needs anyway to be sleepable
         (suggested by Kumar)
       - Test passing a dynamic pointer with NULL data to
         bpf_verify_pkcs7_signature() (suggested by Kumar)
      
      v15:
       - Add kfunc_dynptr_param test to deny list for s390x
      
      v14:
       - Explain that is_dynptr_type_expected() will be useful also for BTF
         (suggested by Joanne)
       - Rename KEY_LOOKUP_FLAGS_ALL to KEY_LOOKUP_ALL (suggested by Jarkko)
       - Swap declaration of spi and dynptr_type in is_dynptr_type_expected()
         (suggested by Joanne)
       - Reimplement kfunc dynptr tests with a regular eBPF program instead of
         executing them with test_verifier (suggested by Joanne)
       - Make key lookup flags as enum so that they are automatically exported
         through BTF (suggested by Alexei)
      
      v13:
       - Split is_dynptr_reg_valid_init() and introduce is_dynptr_type_expected()
         to see if the dynamic pointer type passed as argument to a kfunc is
         supported (suggested by Kumar)
       - Add forward declaration of struct key in include/linux/bpf.h (suggested
         by Song)
       - Declare mask for key lookup flags, remove key_lookup_flags_check()
         (suggested by Jarkko and KP)
       - Allow only certain dynamic pointer types (currently, local) to be passed
         as argument to kfuncs (suggested by Kumar)
       - For each dynamic pointer parameter in kfunc, additionally check if the
         passed pointer is to the stack (suggested by Kumar)
       - Split the validity/initialization and dynamic pointer type check also in
         the verifier, and adjust the expected error message in the test (a test
         for an unexpected dynptr type passed to a helper cannot be added due to
         missing suitable helpers, but this case has been tested manually)
       - Add verifier tests to check the dynamic pointers passed as argument to
         kfuncs (suggested by Kumar)
      
      v12:
       - Put lookup_key and verify_pkcs7_sig tests in deny list for s390x (JIT
         does not support calling kernel function)
      
      v11:
       - Move stringify_struct() macro to include/linux/btf.h (suggested by
         Daniel)
       - Change kernel configuration options in
         tools/testing/selftests/bpf/config* from =m to =y
      
      v10:
       - Introduce key_lookup_flags_check() and system_keyring_id_check() inline
         functions to check parameters (suggested by KP)
       - Fix descriptions and comment of key-related kfuncs (suggested by KP)
       - Register kfunc set only once (suggested by Alexei)
       - Move needed kernel options to the architecture-independent configuration
         for testing
      
      v9:
       - Drop patch to introduce KF_SLEEPABLE kfunc flag (already merged)
       - Rename valid_ptr member of bpf_key to has_ref (suggested by Daniel)
       - Check dynamic pointers in kfunc definition with bpf_dynptr_kern struct
         definition instead of string, to detect structure renames (suggested by
         Daniel)
       - Explicitly say that we permit initialized dynamic pointers in kfunc
         definition (suggested by Daniel)
       - Remove noinline __weak from kfuncs definition (reported by Daniel)
       - Simplify key lookup flags check in bpf_lookup_user_key() (suggested by
         Daniel)
       - Explain the reason for deferring key permission check (suggested by
         Daniel)
       - Allocate memory with GFP_ATOMIC in bpf_lookup_system_key(), and remove
         KF_SLEEPABLE kfunc flag from kfunc declaration (suggested by Daniel)
       - Define only one kfunc set and remove the loop for registration
         (suggested by Alexei)
      
      v8:
       - Define the new bpf_key structure to carry the key pointer and whether
         that pointer is valid or not (suggested by Daniel)
       - Drop patch to mark a kfunc parameter with the __maybe_null suffix
       - Improve documentation of kfuncs
       - Introduce bpf_lookup_system_key() to obtain a key pointer suitable for
         verify_pkcs7_signature() (suggested by Daniel)
       - Use the new kfunc registration API
       - Drop patch to test the __maybe_null suffix
       - Add tests for bpf_lookup_system_key()
      
      v7:
       - Add support for using dynamic and NULL pointers in kfunc (suggested by
         Alexei)
       - Add new kfunc-related tests
      
      v6:
       - Switch back to key lookup helpers + signature verification (until v5),
         and defer permission check from bpf_lookup_user_key() to
         bpf_verify_pkcs7_signature()
       - Add additional key lookup test to illustrate the usage of the
         KEY_LOOKUP_CREATE flag and validate the flags (suggested by Daniel)
       - Make description of flags of bpf_lookup_user_key() more user-friendly
         (suggested by Daniel)
       - Fix validation of flags parameter in bpf_lookup_user_key() (reported by
         Daniel)
       - Rename bpf_verify_pkcs7_signature() keyring-related parameters to
         user_keyring and system_keyring to make their purpose more clear
       - Accept keyring-related parameters of bpf_verify_pkcs7_signature() as
         alternatives (suggested by KP)
       - Replace unsigned long type with u64 in helper declaration (suggested by
         Daniel)
       - Extend the bpf_verify_pkcs7_signature() test by calling the helper
         without data, by ensuring that the helper enforces the keyring-related
         parameters as alternatives, by ensuring that the helper rejects
         inaccessible and expired keyrings, and by checking all system keyrings
       - Move bpf_lookup_user_key() and bpf_key_put() usage tests to
         ref_tracking.c (suggested by John)
       - Call bpf_lookup_user_key() and bpf_key_put() only in sleepable programs
      
      v5:
       - Move KEY_LOOKUP_ to include/linux/key.h
         for validation of bpf_verify_pkcs7_signature() parameter
       - Remove bpf_lookup_user_key() and bpf_key_put() helpers, and the
         corresponding tests
       - Replace struct key parameter of bpf_verify_pkcs7_signature() with the
         keyring serial and lookup flags
       - Call lookup_user_key() and key_put() in bpf_verify_pkcs7_signature()
         code, to ensure that the retrieved key is used according to the
         permission requested at lookup time
       - Clarified keyring precedence in the description of
         bpf_verify_pkcs7_signature() (suggested by John)
       - Remove newline in the second argument of ASSERT_
       - Fix helper prototype regular expression in bpf_doc.py
      
      v4:
       - Remove bpf_request_key_by_id(), don't return an invalid pointer that
         other helpers can use
       - Pass the keyring ID (without ULONG_MAX, suggested by Alexei) to
         bpf_verify_pkcs7_signature()
       - Introduce bpf_lookup_user_key() and bpf_key_put() helpers (suggested by
         Alexei)
       - Add lookup_key_norelease test, to ensure that the verifier blocks eBPF
         programs which don't decrement the key reference count
       - Parse raw PKCS#7 signature instead of module-style signature in the
         verify_pkcs7_signature test (suggested by Alexei)
       - Parse kernel module in user space and pass raw PKCS#7 signature to the
         eBPF program for signature verification
      
      v3:
       - Rename bpf_verify_signature() back to bpf_verify_pkcs7_signature() to
         avoid managing different parameters for each signature verification
         function in one helper (suggested by Daniel)
       - Use dynamic pointers and export bpf_dynptr_get_size() (suggested by
         Alexei)
       - Introduce bpf_request_key_by_id() to give more flexibility to the caller
         of bpf_verify_pkcs7_signature() to retrieve the appropriate keyring
         (suggested by Alexei)
       - Fix test by reordering the gcc command line, always compile sign-file
       - Improve helper support check mechanism in the test
      
      v2:
       - Rename bpf_verify_pkcs7_signature() to a more generic
         bpf_verify_signature() and pass the signature type (suggested by KP)
       - Move the helper and prototype declaration under #ifdef so that user
         space can probe for support for the helper (suggested by Daniel)
       - Describe better the keyring types (suggested by Daniel)
       - Include linux/bpf.h instead of vmlinux.h to avoid implicit or
         redeclaration
       - Make the test selfcontained (suggested by Alexei)
      
      v1:
       - Don't define new map flag but introduce simple wrapper of
         verify_pkcs7_signature() (suggested by Alexei and KP)
      ====================
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      66d6a4bf
    • Roberto Sassu's avatar
      selftests/bpf: Add tests for dynamic pointers parameters in kfuncs · b94fa9f9
      Roberto Sassu authored
      Add tests to ensure that only supported dynamic pointer types are accepted,
      that the passed argument is actually a dynamic pointer, that the passed
      argument is a pointer to the stack, and that bpf_verify_pkcs7_signature()
      correctly handles dynamic pointers with data set to NULL.
      
      The tests are currently in the deny list for s390x (JIT does not support
      calling kernel function).
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-14-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      b94fa9f9
    • Roberto Sassu's avatar
      selftests/bpf: Add test for bpf_verify_pkcs7_signature() kfunc · fc975906
      Roberto Sassu authored
      Perform several tests to ensure the correct implementation of the
      bpf_verify_pkcs7_signature() kfunc.
      
      Do the tests with data signed with a generated testing key (by using
      sign-file from scripts/) and with the tcp_bic.ko kernel module if it is
      found in the system. The test does not fail if tcp_bic.ko is not found.
      
      First, perform an unsuccessful signature verification without data.
      
      Second, perform a successful signature verification with the session
      keyring and a new one created for testing.
      
      Then, ensure that permission and validation checks are done properly on the
      keyring provided to bpf_verify_pkcs7_signature(), despite those checks were
      deferred at the time the keyring was retrieved with bpf_lookup_user_key().
      The tests expect to encounter an error if the Search permission is removed
      from the keyring, or the keyring is expired.
      
      Finally, perform a successful and unsuccessful signature verification with
      the keyrings with pre-determined IDs (the last test fails because the key
      is not in the platform keyring).
      
      The test is currently in the deny list for s390x (JIT does not support
      calling kernel function).
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-13-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      fc975906
    • Roberto Sassu's avatar
      selftests/bpf: Add additional tests for bpf_lookup_*_key() · ecce368d
      Roberto Sassu authored
      Add a test to ensure that bpf_lookup_user_key() creates a referenced
      special keyring when the KEY_LOOKUP_CREATE flag is passed to this function.
      
      Ensure that the kfunc rejects invalid flags.
      
      Ensure that a keyring can be obtained from bpf_lookup_system_key() when one
      of the pre-determined keyring IDs is provided.
      
      The test is currently blacklisted for s390x (JIT does not support calling
      kernel function).
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-12-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      ecce368d
    • Roberto Sassu's avatar
      selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_put() · 7c036ed9
      Roberto Sassu authored
      Add verifier tests for bpf_lookup_*_key() and bpf_key_put(), to ensure that
      acquired key references stored in the bpf_key structure are released, that
      a non-NULL bpf_key pointer is passed to bpf_key_put(), and that key
      references are not leaked.
      
      Also, slightly modify test_verifier.c, to find the BTF ID of the attach
      point for the LSM program type (currently, it is done only for TRACING).
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-11-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      7c036ed9
    • Roberto Sassu's avatar
      selftests/bpf: Compile kernel with everything as built-in · 94fd7420
      Roberto Sassu authored
      Since the eBPF CI does not support kernel modules, change the kernel config
      to compile everything as built-in.
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarDaniel Müller <deso@posteo.net>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-10-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      94fd7420
    • Roberto Sassu's avatar
      bpf: Add bpf_verify_pkcs7_signature() kfunc · 865b0566
      Roberto Sassu authored
      Add the bpf_verify_pkcs7_signature() kfunc, to give eBPF security modules
      the ability to check the validity of a signature against supplied data, by
      using user-provided or system-provided keys as trust anchor.
      
      The new kfunc makes it possible to enforce mandatory policies, as eBPF
      programs might be allowed to make security decisions only based on data
      sources the system administrator approves.
      
      The caller should provide the data to be verified and the signature as eBPF
      dynamic pointers (to minimize the number of parameters) and a bpf_key
      structure containing a reference to the keyring with keys trusted for
      signature verification, obtained from bpf_lookup_user_key() or
      bpf_lookup_system_key().
      
      For bpf_key structures obtained from the former lookup function,
      bpf_verify_pkcs7_signature() completes the permission check deferred by
      that function by calling key_validate(). key_task_permission() is already
      called by the PKCS#7 code.
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarKP Singh <kpsingh@kernel.org>
      Acked-by: default avatarSong Liu <song@kernel.org>
      Link: https://lore.kernel.org/r/20220920075951.929132-9-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      865b0566
    • Roberto Sassu's avatar
      bpf: Add bpf_lookup_*_key() and bpf_key_put() kfuncs · f3cf4134
      Roberto Sassu authored
      Add the bpf_lookup_user_key(), bpf_lookup_system_key() and bpf_key_put()
      kfuncs, to respectively search a key with a given key handle serial number
      and flags, obtain a key from a pre-determined ID defined in
      include/linux/verification.h, and cleanup.
      
      Introduce system_keyring_id_check() to validate the keyring ID parameter of
      bpf_lookup_system_key().
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Acked-by: default avatarSong Liu <song@kernel.org>
      Link: https://lore.kernel.org/r/20220920075951.929132-8-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      f3cf4134
    • Roberto Sassu's avatar
      KEYS: Move KEY_LOOKUP_ to include/linux/key.h and define KEY_LOOKUP_ALL · 90fd8f26
      Roberto Sassu authored
      In preparation for the patch that introduces the bpf_lookup_user_key() eBPF
      kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to
      validate the kfunc parameters. Add them to enum key_lookup_flag, so that
      all the current ones and the ones defined in the future are automatically
      exported through BTF and available to eBPF programs.
      
      Also, add KEY_LOOKUP_ALL to the enum, with the logical OR of currently
      defined flags as value, to facilitate checking whether a variable contains
      only those flags.
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
      Link: https://lore.kernel.org/r/20220920075951.929132-7-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      90fd8f26
    • Roberto Sassu's avatar
      bpf: Export bpf_dynptr_get_size() · 51df4865
      Roberto Sassu authored
      Export bpf_dynptr_get_size(), so that kernel code dealing with eBPF dynamic
      pointers can obtain the real size of data carried by this data structure.
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Reviewed-by: default avatarJoanne Koong <joannelkoong@gmail.com>
      Acked-by: default avatarKP Singh <kpsingh@kernel.org>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-6-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      51df4865
    • Roberto Sassu's avatar
      btf: Allow dynamic pointer parameters in kfuncs · b8d31762
      Roberto Sassu authored
      Allow dynamic pointers (struct bpf_dynptr_kern *) to be specified as
      parameters in kfuncs. Also, ensure that dynamic pointers passed as argument
      are valid and initialized, are a pointer to the stack, and of the type
      local. More dynamic pointer types can be supported in the future.
      
      To properly detect whether a parameter is of the desired type, introduce
      the stringify_struct() macro to compare the returned structure name with
      the desired name. In addition, protect against structure renames, by
      halting the build with BUILD_BUG_ON(), so that developers have to revisit
      the code.
      
      To check if a dynamic pointer passed to the kfunc is valid and initialized,
      and if its type is local, export the existing functions
      is_dynptr_reg_valid_init() and is_dynptr_type_expected().
      
      Cc: Joanne Koong <joannelkoong@gmail.com>
      Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-5-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      b8d31762
    • Roberto Sassu's avatar
      bpf: Move dynptr type check to is_dynptr_type_expected() · e9e315b4
      Roberto Sassu authored
      Move dynptr type check to is_dynptr_type_expected() from
      is_dynptr_reg_valid_init(), so that callers can better determine the cause
      of a negative result (dynamic pointer not valid/initialized, dynamic
      pointer of the wrong type). It will be useful for example for BTF, to
      restrict which dynamic pointer types can be passed to kfuncs, as initially
      only the local type will be supported.
      
      Also, splitting makes the code more readable, since checking the dynamic
      pointer type is not necessarily related to validity and initialization.
      
      Split the validity/initialization and dynamic pointer type check also in
      the verifier, and adjust the expected error message in the test (a test for
      an unexpected dynptr type passed to a helper cannot be added due to missing
      suitable helpers, but this case has been tested manually).
      
      Cc: Joanne Koong <joannelkoong@gmail.com>
      Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-4-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      e9e315b4
    • Roberto Sassu's avatar
      btf: Export bpf_dynptr definition · 00f14641
      Roberto Sassu authored
      eBPF dynamic pointers is a new feature recently added to upstream. It binds
      together a pointer to a memory area and its size. The internal kernel
      structure bpf_dynptr_kern is not accessible by eBPF programs in user space.
      They instead see bpf_dynptr, which is then translated to the internal
      kernel structure by the eBPF verifier.
      
      The problem is that it is not possible to include at the same time the uapi
      include linux/bpf.h and the vmlinux BTF vmlinux.h, as they both contain the
      definition of some structures/enums. The compiler complains saying that the
      structures/enums are redefined.
      
      As bpf_dynptr is defined in the uapi include linux/bpf.h, this makes it
      impossible to include vmlinux.h. However, in some cases, e.g. when using
      kfuncs, vmlinux.h has to be included. The only option until now was to
      include vmlinux.h and add the definition of bpf_dynptr directly in the eBPF
      program source code from linux/bpf.h.
      
      Solve the problem by using the same approach as for bpf_timer (which also
      follows the same scheme with the _kern suffix for the internal kernel
      structure).
      
      Add the following line in one of the dynamic pointer helpers,
      bpf_dynptr_from_mem():
      
      BTF_TYPE_EMIT(struct bpf_dynptr);
      
      Cc: stable@vger.kernel.org
      Cc: Joanne Koong <joannelkoong@gmail.com>
      Fixes: 97e03f52 ("bpf: Add verifier support for dynptrs")
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarYonghong Song <yhs@fb.com>
      Tested-by: default avatarKP Singh <kpsingh@kernel.org>
      Link: https://lore.kernel.org/r/20220920075951.929132-3-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      00f14641
    • KP Singh's avatar
      bpf: Allow kfuncs to be used in LSM programs · d15bf150
      KP Singh authored
      In preparation for the addition of new kfuncs, allow kfuncs defined in the
      tracing subsystem to be used in LSM programs by mapping the LSM program
      type to the TRACING hook.
      Signed-off-by: default avatarKP Singh <kpsingh@kernel.org>
      Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
      Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
      Link: https://lore.kernel.org/r/20220920075951.929132-2-roberto.sassu@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      d15bf150
    • Tao Chen's avatar
      libbpf: Support raw BTF placed in the default search path · 01f2e36c
      Tao Chen authored
      Currently, the default vmlinux files at '/boot/vmlinux-*',
      '/lib/modules/*/vmlinux-*' etc. are parsed with 'btf__parse_elf()' to
      extract BTF. It is possible that these files are actually raw BTF files
      similar to /sys/kernel/btf/vmlinux. So parse these files with
      'btf__parse' which tries both raw format and ELF format.
      
      This might be useful in some scenarios where users put their custom BTF
      into known locations and don't want to specify btf_custom_path option.
      Signed-off-by: default avatarTao Chen <chentao.kernel@linux.alibaba.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Acked-by: default avatarYonghong Song <yhs@fb.com>
      Link: https://lore.kernel.org/bpf/3f59fb5a345d2e4f10e16fe9e35fbc4c03ecaa3e.1662999860.git.chentao.kernel@linux.alibaba.com
      01f2e36c
    • Yauheni Kaliuta's avatar
      selftests: bpf: test_kmod.sh: Pass parameters to the module · 272d1f4c
      Yauheni Kaliuta authored
      It's possible to specify particular tests for test_bpf.ko with
      module parameters. Make it possible to pass the module parameters,
      example:
      
      test_kmod.sh test_range=1,3
      
      Since magnitude tests take long time it can be reasonable to skip
      them.
      Signed-off-by: default avatarYauheni Kaliuta <ykaliuta@redhat.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220908120146.381218-1-ykaliuta@redhat.com
      272d1f4c
    • Yonghong Song's avatar
      libbpf: Improve BPF_PROG2 macro code quality and description · 9f2f5d78
      Yonghong Song authored
      Commit 34586d29 ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2
      macro for trampoline based programs with struct arguments. Andrii
      made a few suggestions to improve code quality and description.
      This patch implemented these suggestions including better internal
      macro name, consistent usage pattern for __builtin_choose_expr(),
      simpler macro definition for always-inline func arguments and
      better macro description.
      Signed-off-by: default avatarYonghong Song <yhs@fb.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Acked-by: default avatarStanislav Fomichev <sdf@google.com>
      Link: https://lore.kernel.org/bpf/20220910025214.1536510-1-yhs@fb.com
      9f2f5d78
  2. 21 Sep, 2022 8 commits
    • Andrii Nakryiko's avatar
      Merge branch 'bpf: Add user-space-publisher ring buffer map type' · c12a0376
      Andrii Nakryiko authored
      David Vernet says:
      
      ====================
      This patch set defines a new map type, BPF_MAP_TYPE_USER_RINGBUF, which
      provides single-user-space-producer / single-kernel-consumer semantics over
      a ring buffer.  Along with the new map type, a helper function called
      bpf_user_ringbuf_drain() is added which allows a BPF program to specify a
      callback with the following signature, to which samples are posted by the
      helper:
      
      void (struct bpf_dynptr *dynptr, void *context);
      
      The program can then use the bpf_dynptr_read() or bpf_dynptr_data() helper
      functions to safely read the sample from the dynptr. There are currently no
      helpers available to determine the size of the sample, but one could easily
      be added if required.
      
      On the user-space side, libbpf has been updated to export a new
      'struct ring_buffer_user' type, along with the following symbols:
      
      struct ring_buffer_user *
      ring_buffer_user__new(int map_fd,
                            const struct ring_buffer_user_opts *opts);
      void ring_buffer_user__free(struct ring_buffer_user *rb);
      void *ring_buffer_user__reserve(struct ring_buffer_user *rb,
      				uint32_t size);
      void *ring_buffer_user__poll(struct ring_buffer_user *rb, uint32_t size,
      			     int timeout_ms);
      void ring_buffer_user__discard(struct ring_buffer_user *rb, void *sample);
      void ring_buffer_user__submit(struct ring_buffer_user *rb, void *sample);
      
      These symbols are exported for inclusion in libbpf version 1.0.0.
      Signed-off-by: default avatarDavid Vernet <void@manifault.com>
      ---
      v5 -> v6:
      - Fixed s/BPF_MAP_TYPE_RINGBUF/BPF_MAP_TYPE_USER_RINGBUF typo in the
        libbpf user ringbuf doxygen header comment for ring_buffer_user__new()
        (Andrii).
      - Specify that pointer returned from ring_buffer_user__reserve() and its
        blocking counterpart is 8-byte aligned (Andrii).
      - Renamed user_ringbuf__commit() to user_ringbuf_commit(), as it's static
        (Andrii).
      - Another slight reworking of user_ring_buffer__reserve_blocking() to
        remove some extraneous nanosecond variables + checking (Andrii).
      - Add a final check of user_ring_buffer__reserve() in
        user_ring_buffer__reserve_blocking().
      - Moved busy bit lock / unlock logic from __bpf_user_ringbuf_peek() to
        bpf_user_ringbuf_drain() (Andrii).
      - -ENOSPC -> -ENODATA for an empty ring buffer in
        __bpf_user_ringbuf_peek() (Andrii).
      - Updated BPF_RB_FORCE_WAKEUP to only force a wakeup notification to be
        sent if even if no sample was drained.
      - Changed a bit of the wording in the UAPI header for
        bpf_user_ringbuf_drain() to mention the BPF_RB_FORCE_WAKEUP behavior.
      - Remove extra space after return in ringbuf_map_poll_user() (Andrii).
      - Removed now-extraneous paragraph from the commit summary of patch 2/4
        (Andrii).
      v4 -> v5:
      - DENYLISTed the user-ringbuf test suite on s390x. We have a number of
        functions in the progs/user_ringbuf_success.c prog that user-space
        fires by invoking a syscall. Not all of these syscalls are available
        on s390x. If and when we add the ability to kick the kernel from
        user-space, or if we end up using iterators for that per Hao's
        suggestion, we could re-enable this test suite on s390x.
      - Fixed a few more places that needed ringbuffer -> ring buffer.
      v3 -> v4:
      - Update BPF_MAX_USER_RINGBUF_SAMPLES to not specify a bit, and instead
        just specify a number of samples. (Andrii)
      - Update "ringbuffer" in comments and commit summaries to say "ring
        buffer". (Andrii)
      - Return -E2BIG from bpf_user_ringbuf_drain() both when a sample can't
        fit into the ring buffer, and when it can't fit into a dynptr. (Andrii)
      - Don't loop over samples in __bpf_user_ringbuf_peek() if a sample was
        discarded. Instead, return -EAGAIN so the caller can deal with it. Also
        updated the caller to detect -EAGAIN and skip over it when iterating.
        (Andrii)
      - Removed the heuristic for notifying user-space when a sample is drained,
        causing the ring buffer to no longer be full. This may be useful in the
        future, but is being removed now because it's strictly a heuristic.
      - Re-add BPF_RB_FORCE_WAKEUP flag to bpf_user_ringbuf_drain(). (Andrii)
      - Remove helper_allocated_dynptr tracker from verifier. (Andrii)
      - Add libbpf function header comments to tools/lib/bpf/libbpf.h, so that
        they will be included in rendered libbpf docs. (Andrii)
      - Add symbols to a new LIBBPF_1.1.0 section in linker version script,
        rather than including them in LIBBPF_1.0.0. (Andrii)
      - Remove libbpf_err() calls from static libbpf functions. (Andrii)
      - Check user_ring_buffer_opts instead of ring_buffer_opts in
        user_ring_buffer__new(). (Andrii)
      - Avoid an extra if in the hot path in user_ringbuf__commit(). (Andrii)
      - Use ENOSPC rather than ENODATA if no space is available in the ring
        buffer. (Andrii)
      - Don't round sample size in header to 8, but still round size that is
        reserved and written to 8, and validate positions are multiples of 8
        (Andrii).
      - Use nanoseconds for most calculations in
        user_ring_buffer__reserve_blocking(). (Andrii)
      - Don't use CHECK() in testcases, instead use ASSERT_*. (Andrii)
      - Use SEC("?raw_tp") instead of SEC("?raw_tp/sys_nanosleep") in negative
        test. (Andrii)
      - Move test_user_ringbuf.h header to live next to BPF program instead of
        a directory up from both it and the user-space test program. (Andrii)
      - Update bpftool help message / docs to also include user_ringbuf.
      v2 -> v3:
      - Lots of formatting fixes, such as keeping things on one line if they fit
        within 100 characters, and removing some extraneous newlines. Applies
        to all diffs in the patch-set. (Andrii)
      - Renamed ring_buffer_user__* symbols to user_ring_buffer__*. (Andrii)
      - Added a missing smb_mb__before_atomic() in
        __bpf_user_ringbuf_sample_release(). (Hao)
      - Restructure how and when notification events are sent from the kernel to
        the user-space producers via the .map_poll() callback for the
        BPF_MAP_TYPE_USER_RINGBUF map. Before, we only sent a notification when
        the ringbuffer was fully drained. Now, we guarantee user-space that
        we'll send an event at least once per bpf_user_ringbuf_drain(), as long
        as at least one sample was drained, and BPF_RB_NO_WAKEUP was not passed.
        As a heuristic, we also send a notification event any time a sample being
        drained causes the ringbuffer to no longer be full. (Andrii)
      - Continuing on the above point, updated
        user_ring_buffer__reserve_blocking() to loop around epoll_wait() until a
        sufficiently large sample is found. (Andrii)
      - Communicate BPF_RINGBUF_BUSY_BIT and BPF_RINGBUF_DISCARD_BIT in sample
        headers. The ringbuffer implementation still only supports
        single-producer semantics, but we can now add synchronization support in
        user_ring_buffer__reserve(), and will automatically get multi-producer
        semantics. (Andrii)
      - Updated some commit summaries, specifically adding more details where
        warranted. (Andrii)
      - Improved function documentation for bpf_user_ringbuf_drain(), more
        clearly explaining all function arguments and return types, as well as
        the semantics for waking up user-space producers.
      - Add function header comments for user_ring_buffer__reserve{_blocking}().
        (Andrii)
      - Rounding-up all samples to 8-bytes in the user-space producer, and
        enforcing that all samples are properly aligned in the kernel. (Andrii)
      - Added testcases that verify that bpf_user_ringbuf_drain() properly
        validates samples, and returns error conditions if any invalid samples
        are encountered. (Andrii)
      - Move atomic_t busy field out of the consumer page, and into the
        struct bpf_ringbuf. (Andrii)
      - Split ringbuf_map_{mmap, poll}_{kern, user}() into separate
        implementations. (Andrii)
      - Don't silently consume errors in bpf_user_ringbuf_drain(). (Andrii)
      - Remove magic number of samples (4096) from bpf_user_ringbuf_drain(),
        and instead use BPF_MAX_USER_RINGBUF_SAMPLES macro, which allows
        128k samples. (Andrii)
      - Remove MEM_ALLOC modifier from PTR_TO_DYNPTR register in verifier, and
        instead rely solely on the register being PTR_TO_DYNPTR. (Andrii)
      - Move freeing of atomic_t busy bit to before we invoke irq_work_queue() in
        __bpf_user_ringbuf_sample_release(). (Andrii)
      - Only check for BPF_RB_NO_WAKEUP flag in bpf_ringbuf_drain().
      - Remove libbpf function names from kernel smp_{load, store}* comments in
        the kernel. (Andrii)
      - Don't use double-underscore naming convention in libbpf functions.
        (Andrii)
      - Use proper __u32 and __u64 for types where we need to guarantee their
        size. (Andrii)
      
      v1 -> v2:
      - Following Joanne landing 88374342 ("bpf: Fix ref_obj_id for dynptr
        data slices in verifier") [0], removed [PATCH 1/5] bpf: Clear callee
        saved regs after updating REG0 [1]. (Joanne)
      - Following the above adjustment, updated check_helper_call() to not store
        a reference for bpf_dynptr_data() if the register containing the dynptr
        is of type MEM_ALLOC. (Joanne)
      - Fixed casting issue pointed out by kernel test robot by adding a missing
        (uintptr_t) cast. (lkp)
      
      [0] https://lore.kernel.org/all/20220809214055.4050604-1-joannelkoong@gmail.com/
      [1] https://lore.kernel.org/all/20220808155341.2479054-1-void@manifault.com/
      ====================
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      c12a0376
    • David Vernet's avatar
      selftests/bpf: Add selftests validating the user ringbuf · e5a9df51
      David Vernet authored
      This change includes selftests that validate the expected behavior and
      APIs of the new BPF_MAP_TYPE_USER_RINGBUF map type.
      Signed-off-by: default avatarDavid Vernet <void@manifault.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220920000100.477320-5-void@manifault.com
      e5a9df51
    • David Vernet's avatar
      bpf: Add libbpf logic for user-space ring buffer · b66ccae0
      David Vernet authored
      Now that all of the logic is in place in the kernel to support user-space
      produced ring buffers, we can add the user-space logic to libbpf. This
      patch therefore adds the following public symbols to libbpf:
      
      struct user_ring_buffer *
      user_ring_buffer__new(int map_fd,
      		      const struct user_ring_buffer_opts *opts);
      void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
      void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
                                               __u32 size, int timeout_ms);
      void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample);
      void user_ring_buffer__discard(struct user_ring_buffer *rb,
      void user_ring_buffer__free(struct user_ring_buffer *rb);
      
      A user-space producer must first create a struct user_ring_buffer * object
      with user_ring_buffer__new(), and can then reserve samples in the
      ring buffer using one of the following two symbols:
      
      void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
      void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
                                               __u32 size, int timeout_ms);
      
      With user_ring_buffer__reserve(), a pointer to a 'size' region of the ring
      buffer will be returned if sufficient space is available in the buffer.
      user_ring_buffer__reserve_blocking() provides similar semantics, but will
      block for up to 'timeout_ms' in epoll_wait if there is insufficient space
      in the buffer. This function has the guarantee from the kernel that it will
      receive at least one event-notification per invocation to
      bpf_ringbuf_drain(), provided that at least one sample is drained, and the
      BPF program did not pass the BPF_RB_NO_WAKEUP flag to bpf_ringbuf_drain().
      
      Once a sample is reserved, it must either be committed to the ring buffer
      with user_ring_buffer__submit(), or discarded with
      user_ring_buffer__discard().
      Signed-off-by: default avatarDavid Vernet <void@manifault.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220920000100.477320-4-void@manifault.com
      b66ccae0
    • David Vernet's avatar
      bpf: Add bpf_user_ringbuf_drain() helper · 20571567
      David Vernet authored
      In a prior change, we added a new BPF_MAP_TYPE_USER_RINGBUF map type which
      will allow user-space applications to publish messages to a ring buffer
      that is consumed by a BPF program in kernel-space. In order for this
      map-type to be useful, it will require a BPF helper function that BPF
      programs can invoke to drain samples from the ring buffer, and invoke
      callbacks on those samples. This change adds that capability via a new BPF
      helper function:
      
      bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx,
                             u64 flags)
      
      BPF programs may invoke this function to run callback_fn() on a series of
      samples in the ring buffer. callback_fn() has the following signature:
      
      long callback_fn(struct bpf_dynptr *dynptr, void *context);
      
      Samples are provided to the callback in the form of struct bpf_dynptr *'s,
      which the program can read using BPF helper functions for querying
      struct bpf_dynptr's.
      
      In order to support bpf_ringbuf_drain(), a new PTR_TO_DYNPTR register
      type is added to the verifier to reflect a dynptr that was allocated by
      a helper function and passed to a BPF program. Unlike PTR_TO_STACK
      dynptrs which are allocated on the stack by a BPF program, PTR_TO_DYNPTR
      dynptrs need not use reference tracking, as the BPF helper is trusted to
      properly free the dynptr before returning. The verifier currently only
      supports PTR_TO_DYNPTR registers that are also DYNPTR_TYPE_LOCAL.
      
      Note that while the corresponding user-space libbpf logic will be added
      in a subsequent patch, this patch does contain an implementation of the
      .map_poll() callback for BPF_MAP_TYPE_USER_RINGBUF maps. This
      .map_poll() callback guarantees that an epoll-waiting user-space
      producer will receive at least one event notification whenever at least
      one sample is drained in an invocation of bpf_user_ringbuf_drain(),
      provided that the function is not invoked with the BPF_RB_NO_WAKEUP
      flag. If the BPF_RB_FORCE_WAKEUP flag is provided, a wakeup
      notification is sent even if no sample was drained.
      Signed-off-by: default avatarDavid Vernet <void@manifault.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220920000100.477320-3-void@manifault.com
      20571567
    • David Vernet's avatar
      bpf: Define new BPF_MAP_TYPE_USER_RINGBUF map type · 583c1f42
      David Vernet authored
      We want to support a ringbuf map type where samples are published from
      user-space, to be consumed by BPF programs. BPF currently supports a
      kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF
      map type.  We'll need to define a new map type for user-space -> kernel,
      as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply
      to a user-space producer ring buffer, and we'll want to add one or
      more helper functions that would not apply for a kernel-producer
      ring buffer.
      
      This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type
      definition. The map type is useless in its current form, as there is no
      way to access or use it for anything until we one or more BPF helpers. A
      follow-on patch will therefore add a new helper function that allows BPF
      programs to run callbacks on samples that are published to the ring
      buffer.
      Signed-off-by: default avatarDavid Vernet <void@manifault.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
      583c1f42
    • William Dean's avatar
      bpf: simplify code in btf_parse_hdr · 3a74904c
      William Dean authored
      It could directly return 'btf_check_sec_info' to simplify code.
      Signed-off-by: default avatarWilliam Dean <williamsukatube@163.com>
      Acked-by: default avatarYonghong Song <yhs@fb.com>
      Link: https://lore.kernel.org/r/20220917084248.3649-1-williamsukatube@163.comSigned-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
      3a74904c
    • Xin Liu's avatar
      libbpf: Fix NULL pointer exception in API btf_dump__dump_type_data · 7620bffb
      Xin Liu authored
      We found that function btf_dump__dump_type_data can be called by the
      user as an API, but in this function, the `opts` parameter may be used
      as a null pointer.This causes `opts->indent_str` to trigger a NULL
      pointer exception.
      
      Fixes: 2ce8450e ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts")
      Signed-off-by: default avatarXin Liu <liuxin350@huawei.com>
      Signed-off-by: default avatarWeibin Kong <kongweibin2@huawei.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220917084809.30770-1-liuxin350@huawei.com
      7620bffb
    • Rong Tao's avatar
      samples/bpf: Replace blk_account_io_done() with __blk_account_io_done() · bc069da6
      Rong Tao authored
      Since commit be6bfe36 ("block: inline hot paths of blk_account_io_*()")
      blk_account_io_*() become inline functions.
      Signed-off-by: default avatarRong Tao <rtoax@foxmail.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Acked-by: default avatarYonghong Song <yhs@fb.com>
      Link: https://lore.kernel.org/bpf/tencent_1CC476835C219FACD84B6715F0D785517E07@qq.com
      bc069da6
  3. 20 Sep, 2022 5 commits
  4. 19 Sep, 2022 1 commit
  5. 17 Sep, 2022 1 commit
  6. 16 Sep, 2022 4 commits
    • Xin Liu's avatar
      libbpf: Clean up legacy bpf maps declaration in bpf_helpers · dc567045
      Xin Liu authored
      Legacy BPF map declarations are no longer supported in libbpf v1.0 [0].
      Only BTF-defined maps are supported starting from v1.0, so it is time to
      remove the definition of bpf_map_def in bpf_helpers.h.
      
        [0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0Signed-off-by: default avatarXin Liu <liuxin350@huawei.com>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Acked-by: default avatarSong Liu <song@kernel.org>
      Link: https://lore.kernel.org/bpf/20220913073643.19960-1-liuxin350@huawei.com
      dc567045
    • Andrii Nakryiko's avatar
      selftests/bpf: Add veristat tool for mass-verifying BPF object files · c8bc5e05
      Andrii Nakryiko authored
      Add a small tool, veristat, that allows mass-verification of
      a set of *libbpf-compatible* BPF ELF object files. For each such object
      file, veristat will attempt to verify each BPF program *individually*.
      Regardless of success or failure, it parses BPF verifier stats and
      outputs them in human-readable table format. In the future we can also
      add CSV and JSON output for more scriptable post-processing, if necessary.
      
      veristat allows to specify a set of stats that should be output and
      ordering between multiple objects and files (e.g., so that one can
      easily order by total instructions processed, instead of default file
      name, prog name, verdict, total instructions order).
      
      This tool should be useful for validating various BPF verifier changes
      or even validating different kernel versions for regressions.
      
      Here's an example for some of the heaviest selftests/bpf BPF object
      files:
      
        $ sudo ./veristat -s insns,file,prog {pyperf,loop,test_verif_scale,strobemeta,test_cls_redirect,profiler}*.linked3.o
        File                                  Program                               Verdict  Duration, us  Total insns  Total states  Peak states
        ------------------------------------  ------------------------------------  -------  ------------  -----------  ------------  -----------
        loop3.linked3.o                       while_true                            failure        350990      1000001          9663         9663
        test_verif_scale3.linked3.o           balancer_ingress                      success        115244       845499          8636         2141
        test_verif_scale2.linked3.o           balancer_ingress                      success         77688       773445          3048          788
        pyperf600.linked3.o                   on_event                              success       2079872       624585         30335        30241
        pyperf600_nounroll.linked3.o          on_event                              success        353972       568128         37101         2115
        strobemeta.linked3.o                  on_event                              success        455230       557149         15915        13537
        test_verif_scale1.linked3.o           balancer_ingress                      success         89880       554754          8636         2141
        strobemeta_nounroll2.linked3.o        on_event                              success        433906       501725         17087         1912
        loop6.linked3.o                       trace_virtqueue_add_sgs               success        282205       398057          8717          919
        loop1.linked3.o                       nested_loops                          success        125630       361349          5504         5504
        pyperf180.linked3.o                   on_event                              success       2511740       160398         11470        11446
        pyperf100.linked3.o                   on_event                              success        744329        87681          6213         6191
        test_cls_redirect.linked3.o           cls_redirect                          success         54087        78925          4782          903
        strobemeta_subprogs.linked3.o         on_event                              success         57898        65420          1954          403
        test_cls_redirect_subprogs.linked3.o  cls_redirect                          success         54522        64965          4619          958
        strobemeta_nounroll1.linked3.o        on_event                              success         43313        57240          1757          382
        pyperf50.linked3.o                    on_event                              success        194355        46378          3263         3241
        profiler2.linked3.o                   tracepoint__syscalls__sys_enter_kill  success         23869        43372          1423          542
        pyperf_subprogs.linked3.o             on_event                              success         29179        36358          2499         2499
        profiler1.linked3.o                   tracepoint__syscalls__sys_enter_kill  success         13052        27036          1946          936
        profiler3.linked3.o                   tracepoint__syscalls__sys_enter_kill  success         21023        26016          2186          915
        profiler2.linked3.o                   kprobe__vfs_link                      success          5255        13896           303          271
        profiler1.linked3.o                   kprobe__vfs_link                      success          7792        12687          1042         1041
        profiler3.linked3.o                   kprobe__vfs_link                      success          7332        10601           865          865
        profiler2.linked3.o                   kprobe_ret__do_filp_open              success          3417         8900           216          199
        profiler2.linked3.o                   kprobe__vfs_symlink                   success          3548         8775           203          186
        pyperf_global.linked3.o               on_event                              success         10007         7563           520          520
        profiler3.linked3.o                   kprobe_ret__do_filp_open              success          4708         6464           532          532
        profiler1.linked3.o                   kprobe_ret__do_filp_open              success          3090         6445           508          508
        profiler3.linked3.o                   kprobe__vfs_symlink                   success          4477         6358           521          521
        profiler1.linked3.o                   kprobe__vfs_symlink                   success          3381         6347           507          507
        profiler2.linked3.o                   raw_tracepoint__sched_process_exec    success          2464         5874           292          189
        profiler3.linked3.o                   raw_tracepoint__sched_process_exec    success          2677         4363           397          283
        profiler2.linked3.o                   kprobe__proc_sys_write                success          1800         4355           143          138
        profiler1.linked3.o                   raw_tracepoint__sched_process_exec    success          1649         4019           333          240
        pyperf600_bpf_loop.linked3.o          on_event                              success          2711         3966           306          306
        profiler2.linked3.o                   raw_tracepoint__sched_process_exit    success          1234         3138            83           66
        profiler3.linked3.o                   kprobe__proc_sys_write                success          1755         2623           223          223
        profiler1.linked3.o                   kprobe__proc_sys_write                success          1222         2456           193          193
        loop2.linked3.o                       while_true                            success           608         1783            57           30
        profiler3.linked3.o                   raw_tracepoint__sched_process_exit    success           789         1680           146          146
        profiler1.linked3.o                   raw_tracepoint__sched_process_exit    success           592         1526           133          133
        strobemeta_bpf_loop.linked3.o         on_event                              success          1015         1512           106          106
        loop4.linked3.o                       combinations                          success           165          524            18           17
        profiler3.linked3.o                   raw_tracepoint__sched_process_fork    success           196          299            25           25
        profiler1.linked3.o                   raw_tracepoint__sched_process_fork    success           109          265            19           19
        profiler2.linked3.o                   raw_tracepoint__sched_process_fork    success           111          265            19           19
        loop5.linked3.o                       while_true                            success            47           84             9            9
        ------------------------------------  ------------------------------------  -------  ------------  -----------  ------------  -----------
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Link: https://lore.kernel.org/bpf/20220909193053.577111-4-andrii@kernel.org
      c8bc5e05
    • Andrii Nakryiko's avatar
      libbpf: Fix crash if SEC("freplace") programs don't have attach_prog_fd set · 749c202c
      Andrii Nakryiko authored
      Fix SIGSEGV caused by libbpf trying to find attach type in vmlinux BTF
      for freplace programs. It's wrong to search in vmlinux BTF and libbpf
      doesn't even mark vmlinux BTF as required for freplace programs. So
      trying to search anything in obj->vmlinux_btf might cause NULL
      dereference if nothing else in BPF object requires vmlinux BTF.
      
      Instead, error out if freplace (EXT) program doesn't specify
      attach_prog_fd during at the load time.
      
      Fixes: 91abb4a6 ("libbpf: Support attachment of BPF tracing programs to kernel modules")
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Link: https://lore.kernel.org/bpf/20220909193053.577111-3-andrii@kernel.org
      749c202c
    • Andrii Nakryiko's avatar
      selftests/bpf: Fix test_verif_scale{1,3} SEC() annotations · cf060c2c
      Andrii Nakryiko authored
      Use proper SEC("tc") for test_verif_scale{1,3} programs. It's not
      a problem for selftests right now because we manually set type
      programmatically, but not having correct SEC() definitions makes it
      harded to generically load BPF object files.
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Link: https://lore.kernel.org/bpf/20220909193053.577111-2-andrii@kernel.org
      cf060c2c