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- 25 Apr, 2024 6 commits
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Eduard Zingerman authored
When doing BPF_PROG_TEST_RUN for bpf_dummy_struct_ops programs, reject execution when NULL is passed for non-nullable params. For programs with non-nullable params verifier assumes that such params are never NULL and thus might optimize out NULL checks. Suggested-by:
Kui-Feng Lee <sinquersw@gmail.com> Signed-off-by:
Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20240424012821.595216-5-eddyz87@gmail.comSigned-off-by:
Alexei Starovoitov <ast@kernel.org>
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Eduard Zingerman authored
dummy_st_ops.test_2 and dummy_st_ops.test_sleepable do not have their 'state' parameter marked as nullable. Update dummy_st_ops.c to avoid passing NULL for such parameters, as the next patch would allow kernel to enforce this restriction. Signed-off-by:
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Eduard Zingerman authored
As reported by Jose E. Marchesi in off-list discussion, GCC and LLVM generate slightly different code for dummy_st_ops_success/test_1(): SEC("struct_ops/test_1") int BPF_PROG(test_1, struct bpf_dummy_ops_state *state) { int ret; if (!state) return 0xf2f3f4f5; ret = state->val; state->val = 0x5a; return ret; } GCC-generated LLVM-generated ---------------------------- --------------------------- 0: r1 = *(u64 *)(r1 + 0x0) 0: w0 = -0xd0c0b0b 1: if r1 == 0x0 goto 5f 1: r1 = *(u64 *)(r1 + 0x0) 2: r0 = *(s32 *)(r1 + 0x0) 2: if r1 == 0x0 goto 6f 3: *(u32 *)(r1 + 0x0) = 0x5a 3: r0 = *(u32 *)(r1 + 0x0) 4: exit 4: w2 = 0x5a 5: r0 = -0xd0c0b0b 5: *(u32 *)(r1 + 0x0) = r2 6: exit 6: exit If the 'state' argument is not marked as nullable in net/bpf/bpf_dummy_struct_ops.c, the verifier would assume that 'r1 == 0x0' is never true: - for the GCC version, this means that instructions #5-6 would be marked as dead and removed; - for the LLVM version, all instructions would be marked as live. The test dummy_st_ops/dummy_init_ret_value actually sets the 'state' parameter to NULL. Therefore, when the 'state' argument is not marked as nullable, the GCC-generated version of the code would trigger a NULL pointer dereference at instruction #3. This patch updates the test_1() test case to always follow a shape similar to the GCC-generated version above, in order to verify whether the 'state' nullability is marked correctly. Reported-by:Jose E. Marchesi <jemarch@gnu.org> Signed-off-by:
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Eduard Zingerman authored
Test case dummy_st_ops/dummy_init_ret_value passes NULL as the first parameter of the test_1() function. Mark this parameter as nullable to make verifier aware of such possibility. Otherwise, NULL check in the test_1() code: SEC("struct_ops/test_1") int BPF_PROG(test_1, struct bpf_dummy_ops_state *state) { if (!state) return ...; ... access state ... } Might be removed by verifier, thus triggering NULL pointer dereference under certain conditions. Reported-by: -
Andrea Righi authored
Add a testcase for the ring_buffer__consume_n() API. The test produces multiple samples in a ring buffer, using a sys_getpid() fentry prog, and consumes them from user-space in batches, rather than consuming all of them greedily, like ring_buffer__consume() does. Signed-off-by:
Andrea Righi <andrea.righi@canonical.com> Signed-off-by:
Andrii Nakryiko <andrii@kernel.org> Acked-by:
Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/lkml/CAEf4BzaR4zqUpDmj44KNLdpJ=Tpa97GrvzuzVNO5nM6b7oWd1w@mail.gmail.com Link: https://lore.kernel.org/bpf/20240425140627.112728-1-andrea.righi@canonical.com
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Alexei Starovoitov authored
Add bpf_guard_preempt() macro that uses newly introduced bpf_preempt_disable/enable() kfuncs to guard a critical section. Signed-off-by:
Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20240424225529.16782-1-alexei.starovoitov@gmail.comSigned-off-by:
Martin KaFai Lau <martin.lau@kernel.org>
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- 24 Apr, 2024 34 commits
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Martin KaFai Lau authored
Vadim Fedorenko says: ==================== This series introduces crypto kfuncs to make BPF programs able to utilize kernel crypto subsystem. Crypto operations made pluggable to avoid extensive growth of kernel when it's not needed. Only skcipher is added within this series, but it can be easily extended to other types of operations. No hardware offload supported as it needs sleepable context which is not available for TX or XDP programs. At the same time crypto context initialization kfunc can only run in sleepable context, that's why it should be run separately and store the result in the map. Selftests show the common way to implement crypto actions in BPF programs. Benchmark is also added to have a baseline. ==================== Signed-off-by: -
Vadim Fedorenko authored
Some simple benchmarks are added to understand the baseline of performance. Signed-off-by:
Vadim Fedorenko <vadfed@meta.com> Link: https://lore.kernel.org/r/20240422225024.2847039-5-vadfed@meta.comSigned-off-by:
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Vadim Fedorenko authored
Add simple tc hook selftests to show the way to work with new crypto BPF API. Some tricky dynptr initialization is used to provide empty iv dynptr. Simple AES-ECB algo is used to demonstrate encryption and decryption of fixed size buffers. Signed-off-by:
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Vadim Fedorenko authored
Implement skcipher crypto in BPF crypto framework. Signed-off-by:
Herbert Xu <herbert@gondor.apana.org.au> Link: https://lore.kernel.org/r/20240422225024.2847039-3-vadfed@meta.comSigned-off-by:
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Vadim Fedorenko authored
Add crypto API support to BPF to be able to decrypt or encrypt packets in TC/XDP BPF programs. Special care should be taken for initialization part of crypto algo because crypto alloc) doesn't work with preemtion disabled, it can be run only in sleepable BPF program. Also async crypto is not supported because of the very same issue - TC/XDP BPF programs are not sleepable. Signed-off-by:
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Haiyue Wang authored
The commit d56b63cf ("bpf: add support for bpf_wq user type") changes the fields support number to 11, just sync the comment. Signed-off-by:
Haiyue Wang <haiyue.wang@intel.com> Acked-by:
Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20240424054526.8031-1-haiyue.wang@intel.comSigned-off-by:
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Alexei Starovoitov authored
The wq test was missing destroy(skel) part which was causing bpf progs to stay loaded. That was causing test_progs to complain with "Failed to unload bpf_testmod.ko from kernel: -11" message, but adding destroy() wasn't enough, since wq callback may be delayed, so loop on unload of bpf_testmod if errno is EAGAIN. Acked-by:
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Martin KaFai Lau authored
Geliang Tang says: ==================== This patchset uses more network helpers in test_sock_addr.c, but first of all, patch 2 is needed to make network_helpers.c independent of test_progs.c. Then network_helpers.h can be included into test_sock_addr.c without compile errors. Patch 1 and patch 2 address Martin's comments for the previous series too. v2: - Only a few minor cleanups to patch 5. ==================== Signed-off-by: -
Geliang Tang authored
This patch uses public helper make_sockaddr() exported in network_helpers.h instead of the local defined function mk_sockaddr() in test_sock_addr.c. This can avoid duplicate code. Signed-off-by:
Geliang Tang <tanggeliang@kylinos.cn> Link: https://lore.kernel.org/r/1473e189d6ca1a3925de4c5354d191a14eca0f3f.1713868264.git.tanggeliang@kylinos.cnSigned-off-by:
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Geliang Tang authored
This patch uses public network helper connect_to_addr() exported in network_helpers.h instead of the local defined function connect_to_server() in test_sock_addr.c. This can avoid duplicate code. Signed-off-by:
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Geliang Tang authored
Include network_helpers.h in test_sock_addr.c, use the newly added public helper start_server_addr() instead of the local defined function start_server(). This can avoid duplicate code. In order to use functions defined in network_helpers.c in test_sock_addr.c, Makefile needs to be updated and <Linux/err.h> needs to be included in network_helpers.h to avoid compilation errors. Signed-off-by:
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Geliang Tang authored
ASSERT helpers defined in test_progs.h shouldn't be used in public functions like open_netns() and close_netns(). Since they depend on test__fail() which defined in test_progs.c. Public functions may be used not only in test_progs.c, but in other tests like test_sock_addr.c in the next commit. This patch uses log_err() to replace ASSERT helpers in open_netns() and close_netns() in network_helpers.c to decouple dependencies, then uses ASSERT_OK_PTR() to check the return values of all open_netns(). Signed-off-by:
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Geliang Tang authored
As Martin mentioned in review comment, there is an existing bug that orig_netns_fd will be leaked in the later "goto fail;" case after open("/proc/self/ns/net") in open_netns() in network_helpers.c. This patch adds "close(token->orig_netns_fd);" before "free(token);" to fix it. Fixes: a3033884 ("selftests/bpf: Move open_netns() and close_netns() into network_helpers.c") Signed-off-by: -
Alexei Starovoitov authored
Kumar Kartikeya Dwivedi says: ==================== Introduce bpf_preempt_{disable,enable} This set introduces two kfuncs, bpf_preempt_disable and bpf_preempt_enable, which are wrappers around preempt_disable and preempt_enable in the kernel. These functions allow a BPF program to have code sections where preemption is disabled. There are multiple use cases that are served by such a feature, a few are listed below: 1. Writing safe per-CPU alogrithms/data structures that work correctly across different contexts. 2. Writing safe per-CPU allocators similar to bpf_memalloc on top of array/arena memory blobs. 3. Writing locking algorithms in BPF programs natively. Note that local_irq_disable/enable equivalent is also needed for proper IRQ context protection, but that is a more involved change and will be sent later. While bpf_preempt_{disable,enable} is not sufficient for all of these usage scenarios on its own, it is still necessary. The same effect as these kfuncs can in some sense be already achieved using the bpf_spin_lock or rcu_read_lock APIs, therefore from the standpoint of kernel functionality exposure in the verifier, this is well understood territory. Note that these helpers do allow calling kernel helpers and kfuncs from within the non-preemptible region (unless sleepable). Otherwise, any locks built using the preemption helpers will be as limited as existing bpf_spin_lock. Nesting is allowed by keeping a counter for tracking remaining enables required to be performed. Similar approach can be applied to rcu_read_locks in a follow up. Changelog ========= v1: https://lore.kernel.org/bpf/20240423061922.2295517-1-memxor@gmail.com * Move kfunc BTF ID declerations above css task kfunc for !CONFIG_CGROUPS config (Alexei) * Add test case for global function call in non-preemptible region (Jiri) ==================== Acked-by: -
Kumar Kartikeya Dwivedi authored
Add tests for nested cases, nested count preservation upon different subprog calls that disable/enable preemption, and test sleepable helper call in non-preemptible regions. 182/1 preempt_lock/preempt_lock_missing_1:OK 182/2 preempt_lock/preempt_lock_missing_2:OK 182/3 preempt_lock/preempt_lock_missing_3:OK 182/4 preempt_lock/preempt_lock_missing_3_minus_2:OK 182/5 preempt_lock/preempt_lock_missing_1_subprog:OK 182/6 preempt_lock/preempt_lock_missing_2_subprog:OK 182/7 preempt_lock/preempt_lock_missing_2_minus_1_subprog:OK 182/8 preempt_lock/preempt_balance:OK 182/9 preempt_lock/preempt_balance_subprog_test:OK 182/10 preempt_lock/preempt_global_subprog_test:OK 182/11 preempt_lock/preempt_sleepable_helper:OK 182 preempt_lock:OK Summary: 1/11 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by:
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Kumar Kartikeya Dwivedi authored
Introduce two new BPF kfuncs, bpf_preempt_disable and bpf_preempt_enable. These kfuncs allow disabling preemption in BPF programs. Nesting is allowed, since the intended use cases includes building native BPF spin locks without kernel helper involvement. Apart from that, this can be used to per-CPU data structures for cases where programs (or userspace) may preempt one or the other. Currently, while per-CPU access is stable, whether it will be consistent is not guaranteed, as only migration is disabled for BPF programs. Global functions are disallowed from being called, but support for them will be added as a follow up not just preempt kfuncs, but rcu_read_lock kfuncs as well. Static subprog calls are permitted. Sleepable helpers and kfuncs are disallowed in non-preemptible regions. Signed-off-by:
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Alexei Starovoitov authored
__bpf_prog_enter_sleepable_recur does recursion check which is not applicable to wq callback. The callback function is part of bpf program and bpf prog might be running on the same cpu. So recursion check would incorrectly prevent callback from running. The code can call __bpf_prog_enter_sleepable(), but run_ctx would be fake, hence use explicit rcu_read_lock_trace(); migrate_disable(); to address this problem. Another reason to open code is __bpf_prog_enter* are not available in !JIT configs. Reported-by:
kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202404241719.IIGdpAku-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202404241811.FFV4Bku3-lkp@intel.com/ Fixes: eb48f6cd ("bpf: wq: add bpf_wq_init") Signed-off-by:
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Alexei Starovoitov authored
Benjamin Tissoires says: ==================== Introduce bpf_wq This is a followup of sleepable bpf_timer[0]. When discussing sleepable bpf_timer, it was thought that we should give a try to bpf_wq, as the 2 APIs are similar but distinct enough to justify a new one. So here it is. I tried to keep as much as possible common code in kernel/bpf/helpers.c but I couldn't get away with code duplication in kernel/bpf/verifier.c. This series introduces a basic bpf_wq support: - creation is supported - assignment is supported - running a simple bpf_wq is also supported. We will probably need to extend the API further with: - a full delayed_work API (can be piggy backed on top with a correct flag) - bpf_wq_cancel() <- apparently not, this is shooting ourself in the foot - bpf_wq_cancel_sync() (for sleepable programs) - documentation --- For reference, the use cases I have in mind: --- Basically, I need to be able to defer a HID-BPF program for the following reasons (from the aforementioned patch): 1. defer an event: Sometimes we receive an out of proximity event, but the device can not be trusted enough, and we need to ensure that we won't receive another one in the following n milliseconds. So we need to wait those n milliseconds, and eventually re-inject that event in the stack. 2. inject new events in reaction to one given event: We might want to transform one given event into several. This is the case for macro keys where a single key press is supposed to send a sequence of key presses. But this could also be used to patch a faulty behavior, if a device forgets to send a release event. 3. communicate with the device in reaction to one event: We might want to communicate back to the device after a given event. For example a device might send us an event saying that it came back from sleeping state and needs to be re-initialized. Currently we can achieve that by keeping a userspace program around, raise a bpf event, and let that userspace program inject the events and commands. However, we are just keeping that program alive as a daemon for just scheduling commands. There is no logic in it, so it doesn't really justify an actual userspace wakeup. So a kernel workqueue seems simpler to handle. bpf_timers are currently running in a soft IRQ context, this patch series implements a sleppable context for them. Cheers, Benjamin [0] https://lore.kernel.org/all/20240408-hid-bpf-sleepable-v6-0-0499ddd91b94@kernel.org/ Changes in v2: - took previous review into account - mainly dropped BPF_F_WQ_SLEEPABLE - Link to v1: https://lore.kernel.org/r/20240416-bpf_wq-v1-0-c9e66092f842@kernel.org ==================== Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-0-6c986a5a741f@kernel.orgSigned-off-by:
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Benjamin Tissoires authored
Allows to test if allocation/free works Signed-off-by:
Benjamin Tissoires <bentiss@kernel.org> Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-16-6c986a5a741f@kernel.orgSigned-off-by:
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Benjamin Tissoires authored
again, copy/paste from bpf_timer_start(). Signed-off-by:
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Benjamin Tissoires authored
We assign the callback and set everything up. The actual tests of these callbacks will be done when bpf_wq_start() is available. Signed-off-by:
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Benjamin Tissoires authored
To support sleepable async callbacks, we need to tell push_async_cb() whether the cb is sleepable or not. The verifier now detects that we are in bpf_wq_set_callback_impl and can allow a sleepable callback to happen. Signed-off-by:
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Benjamin Tissoires authored
Allows to test if allocation/free works Signed-off-by:
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Benjamin Tissoires authored
We need to teach the verifier about the second argument which is declared as void * but which is of type KF_ARG_PTR_TO_MAP. We could have dropped this extra case if we declared the second argument as struct bpf_map *, but that means users will have to do extra casting to have their program compile. We also need to duplicate the timer code for the checking if the map argument is matching the provided workqueue. Signed-off-by:
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Benjamin Tissoires authored
We simply try in all supported map types if we can store/load a bpf_wq. Signed-off-by:
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Benjamin Tissoires authored
Currently bpf_wq_cancel_and_free() is just a placeholder as there is no memory allocation for bpf_wq just yet. Again, duplication of the bpf_timer approach Signed-off-by:
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Benjamin Tissoires authored
Introduce support for KF_ARG_PTR_TO_WORKQUEUE. The kfuncs will use bpf_wq as argument and that will be recognized as workqueue argument by verifier. bpf_wq_kern casting can happen inside kfunc, but using bpf_wq in argument makes life easier for users who work with non-kern type in BPF progs. Duplicate process_timer_func into process_wq_func. meta argument is only needed to ensure bpf_wq_init's workqueue and map arguments are coming from the same map (map_uid logic is necessary for correct inner-map handling), so also amend check_kfunc_args() to match what helpers functions check is doing. Signed-off-by:
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Benjamin Tissoires authored
When a kfunc is declared with a KF_ARG_PTR_TO_MAP, we should have reg->map_ptr set to a non NULL value, otherwise, that means that the underlying type is not a map. Signed-off-by:
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Benjamin Tissoires authored
cp include/uapi/linux/bpf.h tools/include/uapi/linux/bpf.h Signed-off-by:
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Benjamin Tissoires authored
Mostly a copy/paste from the bpf_timer API, without the initialization and free, as they will be done in a separate patch. Signed-off-by:
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Benjamin Tissoires authored
Same reason than most bpf_timer* functions, we need almost the same for workqueues. So extract the generic part out of it so bpf_wq_cancel_and_free can reuse it. Signed-off-by:
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Benjamin Tissoires authored
In the same way we have a generic __bpf_async_init(), we also need to share code between timer and workqueue for the set_callback call. We just add an unused flags parameter, as it will be used for workqueues. Signed-off-by:
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Benjamin Tissoires authored
No code change except for the new flags argument being stored in the local data struct. Signed-off-by:
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Benjamin Tissoires authored
To be able to add workqueues and reuse most of the timer code, we need to make bpf_hrtimer more generic. There is no code change except that the new struct gets a new u64 flags attribute. We are still below 2 cache lines, so this shouldn't impact the current running codes. The ordering is also changed. Everything related to async callback is now on top of bpf_hrtimer. Signed-off-by:
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