- 19 Dec, 2021 1 commit
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Kumar Kartikeya Dwivedi authored
Allow passing PTR_TO_CTX, if the kfunc expects a matching struct type, and punt to PTR_TO_MEM block if reg->type does not fall in one of PTR_TO_BTF_ID or PTR_TO_SOCK* types. This will be used by future commits to get access to XDP and TC PTR_TO_CTX, and pass various data (flags, l4proto, netns_id, etc.) encoded in opts struct passed as pointer to kfunc. For PTR_TO_MEM support, arguments are currently limited to pointer to scalar, or pointer to struct composed of scalars. This is done so that unsafe scenarios (like passing PTR_TO_MEM where PTR_TO_BTF_ID of in-kernel valid structure is expected, which may have pointers) are avoided. Since the argument checking happens basd on argument register type, it is not easy to ascertain what the expected type is. In the future, support for PTR_TO_MEM for kfunc can be extended to serve other usecases. The struct type whose pointer is passed in may have maximum nesting depth of 4, all recursively composed of scalars or struct with scalars. Future commits will add negative tests that check whether these restrictions imposed for kfunc arguments are duly rejected by BPF verifier or not. Signed-off-by:
Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211217015031.1278167-4-memxor@gmail.com
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- 18 Dec, 2021 10 commits
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Alexei Starovoitov authored
Hao Luo says: ==================== This patch set consists of two changes: - a cleanup of arg_type, ret_type and reg_type which try to make those types composable. (patch 1/9 - patch 6/9) - a bug fix that prevents bpf programs from writing kernel memory. (patch 7/9 - patch 9/9) The purpose of the cleanup is to find a scalable way to express type nullness and read-onliness. This patchset introduces two flags that can be applied on all three types: PTR_MAYBE_NULL and MEM_RDONLY. Previous types such as ARG_XXX_OR_NULL can now be written as ARG_XXX | PTR_MAYBE_NULL Similarly, PTR_TO_RDONLY_BUF is now "PTR_TO_BUF | MEM_RDONLY". Flags can be composed, as ARGs can be both MEM_RDONLY and MAYBE_NULL. ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY Based on this new composable types, patch 7/9 applies MEM_RDONLY on PTR_TO_MEM, in order to tag the returned memory from per_cpu_ptr as read-only. Therefore fixing a previous bug that one can leverage per_cpu_ptr to modify kernel memory within BPF programs. Patch 8/9 generalizes the use of MEM_RDONLY further by tagging a set of helper arguments ARG_PTR_TO_MEM with MEM_RDONLY. Some helper functions may override their arguments, such as bpf_d_path, bpf_snprintf. In this patch, we narrow the ARG_PTR_TO_MEM to be compatible with only a subset of memory types. This prevents these helpers from writing read-only memories. For the helpers that do not write its arguments, we add tag MEM_RDONLY to allow taking a RDONLY memory as argument. Changes since v1: - use %u to print base_type(type) instead of %lu. (Andrii, patch 3/9) - improve reg_type_str() by appending '_or_null' and prepending 'rdonly_'. use preallocated buffer in 'bpf_env'. - unified handling of the previous XXX_OR_NULL in adjust_ptr_min_max_vals (Andrii, patch 4/9) - move PTR_TO_MAP_KEY up to PTR_TO_MAP_VALUE so that we don't have to change to drivers that assume the numeric values of bpf_reg. (patch 4/9) - reintroduce the typo from previous commits in fixes tags (Andrii, patch 7/9) - extensive comments on the reason behind folding flags in check_reg_type (Andrii, patch 8/9) Changes since RFC v2: - renamed BPF_BASE_TYPE to a more succinct name base_type and move its definition to bpf_verifier.h. Same for BPF_TYPE_FLAG. (Alexei) - made checking MEM_RDONLY in check_reg_type() universal (Alexei) - ran through majority of test_progs and fixed bugs in RFC v2: - fixed incorrect BPF_BASE_TYPE_MASK. The high bit of GENMASK should be BITS - 1, rather than BITS. patch 1/9. - fixed incorrect conditions when checking ARG_PTR_TO_MAP_VALUE in check_func_arg(). See patch 2/9. - fixed a bug where PTR_TO_BTF_ID may be combined with MEM_RDONLY, causing the check in check_mem_access() to fall through to the 'else' branch. See check_helper_call() in patch 7/9. - fixed build failure on netronome driver. Entries in bpf_reg_type have been ordered. patch 4/9. - fixed build warnings of using '%d' to print base_type. patch 4/9 - unify arg_type_may_be_null() and reg_type_may_be_null() into a single type_may_be_null(). Previous versions: v1: https://lwn.net/Articles/877938/ RFC v2: https://lwn.net/Articles/877171/ RFC v1: https://lore.kernel.org/bpf/20211109003052.3499225-1-haoluo@google.com/T/ https://lore.kernel.org/bpf/20211109021624.1140446-8-haoluo@google.com/T/ ==================== Signed-off-by: -
Hao Luo authored
This test verifies that a ksym of non-struct can not be directly updated. Signed-off-by:
Hao Luo <haoluo@google.com> Signed-off-by:
Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211217003152.48334-10-haoluo@google.com
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Hao Luo authored
Some helper functions may modify its arguments, for example, bpf_d_path, bpf_get_stack etc. Previously, their argument types were marked as ARG_PTR_TO_MEM, which is compatible with read-only mem types, such as PTR_TO_RDONLY_BUF. Therefore it's legitimate, but technically incorrect, to modify a read-only memory by passing it into one of such helper functions. This patch tags the bpf_args compatible with immutable memory with MEM_RDONLY flag. The arguments that don't have this flag will be only compatible with mutable memory types, preventing the helper from modifying a read-only memory. The bpf_args that have MEM_RDONLY are compatible with both mutable memory and immutable memory. Signed-off-by:
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Hao Luo authored
Tag the return type of {per, this}_cpu_ptr with RDONLY_MEM. The returned value of this pair of helpers is kernel object, which can not be updated by bpf programs. Previously these two helpers return PTR_OT_MEM for kernel objects of scalar type, which allows one to directly modify the memory. Now with RDONLY_MEM tagging, the verifier will reject programs that write into RDONLY_MEM. Fixes: 63d9b80d ("bpf: Introducte bpf_this_cpu_ptr()") Fixes: eaa6bcb7 ("bpf: Introduce bpf_per_cpu_ptr()") Fixes: 4976b718 ("bpf: Introduce pseudo_btf_id") Signed-off-by: -
Hao Luo authored
Remove PTR_TO_MEM_OR_NULL and replace it with PTR_TO_MEM combined with flag PTR_MAYBE_NULL. Signed-off-by:
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Hao Luo authored
This patch introduce a flag MEM_RDONLY to tag a reg value pointing to read-only memory. It makes the following changes: 1. PTR_TO_RDWR_BUF -> PTR_TO_BUF 2. PTR_TO_RDONLY_BUF -> PTR_TO_BUF | MEM_RDONLY Signed-off-by:
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Hao Luo authored
We have introduced a new type to make bpf_reg composable, by allocating bits in the type to represent flags. One of the flags is PTR_MAYBE_NULL which indicates a pointer may be NULL. This patch switches the qualified reg_types to use this flag. The reg_types changed in this patch include: 1. PTR_TO_MAP_VALUE_OR_NULL 2. PTR_TO_SOCKET_OR_NULL 3. PTR_TO_SOCK_COMMON_OR_NULL 4. PTR_TO_TCP_SOCK_OR_NULL 5. PTR_TO_BTF_ID_OR_NULL 6. PTR_TO_MEM_OR_NULL 7. PTR_TO_RDONLY_BUF_OR_NULL 8. PTR_TO_RDWR_BUF_OR_NULL Signed-off-by:
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Hao Luo authored
We have introduced a new type to make bpf_ret composable, by reserving high bits to represent flags. One of the flag is PTR_MAYBE_NULL, which indicates a pointer may be NULL. When applying this flag to ret_types, it means the returned value could be a NULL pointer. This patch switches the qualified arg_types to use this flag. The ret_types changed in this patch include: 1. RET_PTR_TO_MAP_VALUE_OR_NULL 2. RET_PTR_TO_SOCKET_OR_NULL 3. RET_PTR_TO_TCP_SOCK_OR_NULL 4. RET_PTR_TO_SOCK_COMMON_OR_NULL 5. RET_PTR_TO_ALLOC_MEM_OR_NULL 6. RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL 7. RET_PTR_TO_BTF_ID_OR_NULL This patch doesn't eliminate the use of these names, instead it makes them aliases to 'RET_PTR_TO_XXX | PTR_MAYBE_NULL'. Signed-off-by:
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Hao Luo authored
We have introduced a new type to make bpf_arg composable, by reserving high bits of bpf_arg to represent flags of a type. One of the flags is PTR_MAYBE_NULL which indicates a pointer may be NULL. When applying this flag to an arg_type, it means the arg can take NULL pointer. This patch switches the qualified arg_types to use this flag. The arg_types changed in this patch include: 1. ARG_PTR_TO_MAP_VALUE_OR_NULL 2. ARG_PTR_TO_MEM_OR_NULL 3. ARG_PTR_TO_CTX_OR_NULL 4. ARG_PTR_TO_SOCKET_OR_NULL 5. ARG_PTR_TO_ALLOC_MEM_OR_NULL 6. ARG_PTR_TO_STACK_OR_NULL This patch does not eliminate the use of these arg_types, instead it makes them an alias to the 'ARG_XXX | PTR_MAYBE_NULL'. Signed-off-by:
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Hao Luo authored
There are some common properties shared between bpf reg, ret and arg values. For instance, a value may be a NULL pointer, or a pointer to a read-only memory. Previously, to express these properties, enumeration was used. For example, in order to test whether a reg value can be NULL, reg_type_may_be_null() simply enumerates all types that are possibly NULL. The problem of this approach is that it's not scalable and causes a lot of duplication. These properties can be combined, for example, a type could be either MAYBE_NULL or RDONLY, or both. This patch series rewrites the layout of reg_type, arg_type and ret_type, so that common properties can be extracted and represented as composable flag. For example, one can write ARG_PTR_TO_MEM | PTR_MAYBE_NULL which is equivalent to the previous ARG_PTR_TO_MEM_OR_NULL The type ARG_PTR_TO_MEM are called "base type" in this patch. Base types can be extended with flags. A flag occupies the higher bits while base types sits in the lower bits. This patch in particular sets up a set of macro for this purpose. The following patches will rewrite arg_types, ret_types and reg_types respectively. Signed-off-by:
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- 17 Dec, 2021 6 commits
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Andrii Nakryiko authored
Reimplement bpf_probe_large_insn_limit() in bpftool, as that libbpf API is scheduled for deprecation in v0.8. Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Acked-by:
Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20211217171202.3352835-4-andrii@kernel.org
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Andrii Nakryiko authored
Add selftests for prog/map/prog+helper feature probing APIs. Prog and map selftests are designed in such a way that they will always test all the possible prog/map types, based on running kernel's vmlinux BTF enum definition. This way we'll always be sure that when adding new BPF program types or map types, libbpf will be always updated accordingly to be able to feature-detect them. BPF prog_helper selftest will have to be manually extended with interesting and important prog+helper combinations, it's easy, but can't be completely automated. Signed-off-by:
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Andrii Nakryiko authored
Create three extensible alternatives to inconsistently named feature-probing APIs: - libbpf_probe_bpf_prog_type() instead of bpf_probe_prog_type(); - libbpf_probe_bpf_map_type() instead of bpf_probe_map_type(); - libbpf_probe_bpf_helper() instead of bpf_probe_helper(). Set up return values such that libbpf can report errors (e.g., if some combination of input arguments isn't possible to validate, etc), in addition to whether the feature is supported (return value 1) or not supported (return value 0). Also schedule deprecation of those three APIs. Also schedule deprecation of bpf_probe_large_insn_limit(). Also fix all the existing detection logic for various program and map types that never worked: - BPF_PROG_TYPE_LIRC_MODE2; - BPF_PROG_TYPE_TRACING; - BPF_PROG_TYPE_LSM; - BPF_PROG_TYPE_EXT; - BPF_PROG_TYPE_SYSCALL; - BPF_PROG_TYPE_STRUCT_OPS; - BPF_MAP_TYPE_STRUCT_OPS; - BPF_MAP_TYPE_BLOOM_FILTER. Above prog/map types needed special setups and detection logic to work. Subsequent patch adds selftests that will make sure that all the detection logic keeps working for all current and future program and map types, avoiding otherwise inevitable bit rot. [0] Closes: https://github.com/libbpf/libbpf/issues/312Signed-off-by:
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Christy Lee authored
Backtracking information is very verbose, don't print it in log level 1 to improve readability. Signed-off-by:
Christy Lee <christylee@fb.com> Signed-off-by:
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Christy Lee authored
Make the verifier logs more readable, print the verifier states on the corresponding instruction line. If the previous line was not a bpf instruction, then print the verifier states on its own line. Before: Validating test_pkt_access_subprog3() func#3... 86: R1=invP(id=0) R2=ctx(id=0,off=0,imm=0) R10=fp0 ; int test_pkt_access_subprog3(int val, struct __sk_buff *skb) 86: (bf) r6 = r2 87: R2=ctx(id=0,off=0,imm=0) R6_w=ctx(id=0,off=0,imm=0) 87: (bc) w7 = w1 88: R1=invP(id=0) R7_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ; return get_skb_len(skb) * get_skb_ifindex(val, skb, get_constant(123)); 88: (bf) r1 = r6 89: R1_w=ctx(id=0,off=0,imm=0) R6_w=ctx(id=0,off=0,imm=0) 89: (85) call pc+9 Func#4 is global and valid. Skipping. 90: R0_w=invP(id=0) 90: (bc) w8 = w0 91: R0_w=invP(id=0) R8_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ; return get_skb_len(skb) * get_skb_ifindex(val, skb, get_constant(123)); 91: (b7) r1 = 123 92: R1_w=invP123 92: (85) call pc+65 Func#5 is global and valid. Skipping. 93: R0=invP(id=0) After: 86: R1=invP(id=0) R2=ctx(id=0,off=0,imm=0) R10=fp0 ; int test_pkt_access_subprog3(int val, struct __sk_buff *skb) 86: (bf) r6 = r2 ; R2=ctx(id=0,off=0,imm=0) R6_w=ctx(id=0,off=0,imm=0) 87: (bc) w7 = w1 ; R1=invP(id=0) R7_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ; return get_skb_len(skb) * get_skb_ifindex(val, skb, get_constant(123)); 88: (bf) r1 = r6 ; R1_w=ctx(id=0,off=0,imm=0) R6_w=ctx(id=0,off=0,imm=0) 89: (85) call pc+9 Func#4 is global and valid. Skipping. 90: R0_w=invP(id=0) 90: (bc) w8 = w0 ; R0_w=invP(id=0) R8_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ; return get_skb_len(skb) * get_skb_ifindex(val, skb, get_constant(123)); 91: (b7) r1 = 123 ; R1_w=invP123 92: (85) call pc+65 Func#5 is global and valid. Skipping. 93: R0=invP(id=0) Signed-off-by:
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Christy Lee authored
When printing verifier state for any log level, print full verifier state only on function calls or on errors. Otherwise, only print the registers and stack slots that were accessed. Log size differences: verif_scale_loop6 before: 234566564 verif_scale_loop6 after: 72143943 69% size reduction kfree_skb before: 166406 kfree_skb after: 55386 69% size reduction Before: 156: (61) r0 = *(u32 *)(r1 +0) 157: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R1=ctx(id=0,off=0,imm=0) R2_w=invP0 R10=fp0 fp-8_w=00000000 fp-16_w=00\ 000000 fp-24_w=00000000 fp-32_w=00000000 fp-40_w=00000000 fp-48_w=00000000 fp-56_w=00000000 fp-64_w=00000000 fp-72_w=00000000 fp-80_w=00000\ 000 fp-88_w=00000000 fp-96_w=00000000 fp-104_w=00000000 fp-112_w=00000000 fp-120_w=00000000 fp-128_w=00000000 fp-136_w=00000000 fp-144_w=00\ 000000 fp-152_w=00000000 fp-160_w=00000000 fp-168_w=00000000 fp-176_w=00000000 fp-184_w=00000000 fp-192_w=00000000 fp-200_w=00000000 fp-208\ _w=00000000 fp-216_w=00000000 fp-224_w=00000000 fp-232_w=00000000 fp-240_w=00000000 fp-248_w=00000000 fp-256_w=00000000 fp-264_w=00000000 f\ p-272_w=00000000 fp-280_w=00000000 fp-288_w=00000000 fp-296_w=00000000 fp-304_w=00000000 fp-312_w=00000000 fp-320_w=00000000 fp-328_w=00000\ 000 fp-336_w=00000000 fp-344_w=00000000 fp-352_w=00000000 fp-360_w=00000000 fp-368_w=00000000 fp-376_w=00000000 fp-384_w=00000000 fp-392_w=\ 00000000 fp-400_w=00000000 fp-408_w=00000000 fp-416_w=00000000 fp-424_w=00000000 fp-432_w=00000000 fp-440_w=00000000 fp-448_w=00000000 ; return skb->len; 157: (95) exit Func#4 is safe for any args that match its prototype Validating get_constant() func#5... 158: R1=invP(id=0) R10=fp0 ; int get_constant(long val) 158: (bf) r0 = r1 159: R0_w=invP(id=1) R1=invP(id=1) R10=fp0 ; return val - 122; 159: (04) w0 += -122 160: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R1=invP(id=1) R10=fp0 ; return val - 122; 160: (95) exit Func#5 is safe for any args that match its prototype Validating get_skb_ifindex() func#6... 161: R1=invP(id=0) R2=ctx(id=0,off=0,imm=0) R3=invP(id=0) R10=fp0 ; int get_skb_ifindex(int val, struct __sk_buff *skb, int var) 161: (bc) w0 = w3 162: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R1=invP(id=0) R2=ctx(id=0,off=0,imm=0) R3=invP(id=0) R10=fp0 After: 156: (61) r0 = *(u32 *)(r1 +0) 157: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R1=ctx(id=0,off=0,imm=0) ; return skb->len; 157: (95) exit Func#4 is safe for any args that match its prototype Validating get_constant() func#5... 158: R1=invP(id=0) R10=fp0 ; int get_constant(long val) 158: (bf) r0 = r1 159: R0_w=invP(id=1) R1=invP(id=1) ; return val - 122; 159: (04) w0 += -122 160: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ; return val - 122; 160: (95) exit Func#5 is safe for any args that match its prototype Validating get_skb_ifindex() func#6... 161: R1=invP(id=0) R2=ctx(id=0,off=0,imm=0) R3=invP(id=0) R10=fp0 ; int get_skb_ifindex(int val, struct __sk_buff *skb, int var) 161: (bc) w0 = w3 162: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R3=invP(id=0) Signed-off-by:
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- 16 Dec, 2021 11 commits
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Alexei Starovoitov authored
Jakub Kicinski says: ==================== Changes to bpf.h tend to clog up our build systems. The netdev/bpf build bot does incremental builds to save time (reusing the build directory to only rebuild changed objects). This is the rough breakdown of how many objects needs to be rebuilt based on file touched: kernel.h 40633 bpf.h 17881 bpf-cgroup.h 17875 skbuff.h 10696 bpf-netns.h 7604 netdevice.h 7452 filter.h 5003 sock.h 4959 tcp.h 4048 As the stats show touching bpf.h is _very_ expensive. Bulk of the objects get rebuilt because MM includes cgroup headers. Luckily bpf-cgroup.h does not fundamentally depend on bpf.h so we can break that dependency and reduce the number of objects. With the patches applied touching bpf.h causes 5019 objects to be rebuilt (17881 / 5019 = 3.56x). That's pretty much down to filter.h plus noise. v2: Try to make the new headers wider in scope. Collapse bpf-link and bpf-cgroup-types into one header, which may serve as "BPF kernel API" header in the future if needed. Rename bpf-cgroup-storage.h to bpf-inlines.h. Add a fix for the s390 build issue. v3: https://lore.kernel.org/all/20211215061916.715513-1-kuba@kernel.org/ Merge bpf-includes.h into bpf.h. v4: https://lore.kernel.org/all/20211215181231.1053479-1-kuba@kernel.org/ Change course - break off cgroup instead of breaking off bpf. v5: Add forward declaration of struct bpf_prog to perf_event.h when !CONFIG_BPF_SYSCALL (kbuild bot). ==================== Signed-off-by:
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Jakub Kicinski authored
Remove the dependency from cgroup-defs.h to bpf-cgroup.h and bpf.h. This reduces the incremental build size of x86 allmodconfig after bpf.h was touched from ~17k objects rebuilt to ~5k objects. bpf.h is 2.2kLoC and is modified relatively often. We need a new header with just the definition of struct cgroup_bpf and enum cgroup_bpf_attach_type, this is akin to cgroup-defs.h. Signed-off-by:
Jakub Kicinski <kuba@kernel.org> Signed-off-by:
Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/bpf/20211216025538.1649516-4-kuba@kernel.org
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Jakub Kicinski authored
We're about to break the cgroup-defs.h -> bpf-cgroup.h dependency, make sure those who actually need more than the definition of struct cgroup_bpf include bpf-cgroup.h explicitly. Signed-off-by:
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Jakub Kicinski authored
cgroup pulls in BPF which pulls in a lot of includes. We're about to break that chain so fix those who were depending on it. Signed-off-by:
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Andrii Nakryiko authored
Jean-Philippe Brucker says: ==================== Since v1 [1], I added Quentin's acks and applied Andrii's suggestions: * Pass CFLAGS to libbpf link in patch 3 * Substitute CLANG_CROSS_FLAGS whole in HOST_CFLAGS to avoid accidents, patch 4 Add support for cross-building BPF tools and selftests with clang, by passing LLVM=1 or CC=clang to make, as well as CROSS_COMPILE. A single clang toolchain can generate binaries for multiple architectures, so instead of having prefixes such as aarch64-linux-gnu-gcc, clang uses the -target parameter: `clang -target aarch64-linux-gnu'. Patch 1 adds the parameter in Makefile.include so tools can easily support this. Patch 2 prepares for the libbpf change from patch 3 (keep building resolve_btfids's libbpf in the host arch, when cross-building the kernel with clang). Patches 3-6 enable cross-building BPF tools with clang. [1] https://lore.kernel.org/bpf/20211122192019.1277299-1-jean-philippe@linaro.org/ ==================== Signed-off-by:
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Jean-Philippe Brucker authored
Cross building using clang requires passing the "-target" flag rather than using the CROSS_COMPILE prefix. Makefile.include transforms CROSS_COMPILE into CLANG_CROSS_FLAGS. Clear CROSS_COMPILE for bpftool and the host libbpf, and use the clang flags for urandom_read and bench. Signed-off-by:
Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by:
Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20211216163842.829836-7-jean-philippe@linaro.org
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Jean-Philippe Brucker authored
Cross-building using clang requires passing the "-target" flag rather than using the CROSS_COMPILE prefix. Makefile.include transforms CROSS_COMPILE into CLANG_CROSS_FLAGS. Add them to CFLAGS, and erase CROSS_COMPILE for the bpftool build, since it needs to be executed on the host. Signed-off-by:
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Jean-Philippe Brucker authored
Cross-building using clang requires passing the "-target" flag rather than using the CROSS_COMPILE prefix. Makefile.include transforms CROSS_COMPILE into CLANG_CROSS_FLAGS, and adds that to CFLAGS. Remove the cross flags for the bootstrap bpftool, and erase the CROSS_COMPILE flag for the bootstrap libbpf. Signed-off-by:
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Jean-Philippe Brucker authored
Cross-building using clang requires passing the "-target" flag rather than using the CROSS_COMPILE prefix. Makefile.include transforms CROSS_COMPILE into CLANG_CROSS_FLAGS. Add them to the CFLAGS. Signed-off-by:
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Jean-Philippe Brucker authored
The CROSS_COMPILE variable may be present during resolve_btfids build if the kernel is being cross-built. Since resolve_btfids is always executed on the host, we set CC to HOSTCC in order to use the host toolchain when cross-building with GCC. But instead of a toolchain prefix, cross-build with clang uses a "-target" parameter, which Makefile.include deduces from the CROSS_COMPILE variable. In order to avoid cross-building libbpf, clear CROSS_COMPILE before building resolve_btfids. Signed-off-by:
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Jean-Philippe Brucker authored
Cross-compilation with clang uses the -target parameter rather than a toolchain prefix. Just like the kernel Makefile, add that parameter to CFLAGS when CROSS_COMPILE is set. Unlike the kernel Makefile, we use the --sysroot and --gcc-toolchain options because unlike the kernel, tools require standard libraries. Commit c91d4e47 ("Makefile: Remove '--gcc-toolchain' flag") provides some background about --gcc-toolchain. Normally clang finds on its own the additional utilities and libraries that it needs (for example GNU ld or glibc). On some systems however, this autodetection doesn't work. There, our only recourse is asking GCC directly, and pass the result to --sysroot and --gcc-toolchain. Of course that only works when a cross GCC is available. Autodetection worked fine on Debian, but to use the aarch64-linux-gnu toolchain from Archlinux I needed both --sysroot (for crt1.o) and --gcc-toolchain (for crtbegin.o, -lgcc). The --prefix parameter wasn't needed there, but it might be useful on other distributions. Use the CLANG_CROSS_FLAGS variable instead of CLANG_FLAGS because it allows tools such as bpftool, that need to build both host and target binaries, to easily filter out the cross-build flags from CFLAGS. Signed-off-by:
Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/bpf/20211216163842.829836-2-jean-philippe@linaro.org
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- 15 Dec, 2021 1 commit
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Andrii Nakryiko authored
Fix possible read beyond ELF "license" data section if the license string is not properly zero-terminated. Use the fact that libbpf_strlcpy never accesses the (N-1)st byte of the source string because it's replaced with '\0' anyways. If this happens, it's a violation of contract between libbpf and a user, but not handling this more robustly upsets CIFuzz, so given the fix is trivial, let's fix the potential issue. Fixes: 9fc205b4 ("libbpf: Add sane strncpy alternative and use it internally") Signed-off-by:
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- 14 Dec, 2021 9 commits
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Andrii Nakryiko authored
Kui-Feng Lee says: ==================== bpf_object__find_program_by_title is going to be deprecated since v0.7. Replace all use cases with bpf_object__find_program_by_name if possible, or use bpf_object__for_each_program to iterate over programs, matching section names. V3 fixes a broken test case, fexit_bpf2bpf, in selftests/bpf, using bpf_obj__for_each_program API instead. [v2] https://lore.kernel.org/bpf/20211211003608.2764928-1-kuifeng@fb.com/ [v1] https://lore.kernel.org/bpf/20211210190855.1369060-1-kuifeng@fb.com/T/ ==================== Signed-off-by:
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Kui-Feng Lee authored
Deprecate this API since v0.7. All callers should move to bpf_object__find_program_by_name if possible, otherwise use bpf_object__for_each_program to find a program out from a given section. [0] Closes: https://github.com/libbpf/libbpf/issues/292Signed-off-by:
Kui-Feng Lee <kuifeng@fb.com> Signed-off-by:
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Kui-Feng Lee authored
bpf_obj__find_program_by_title() in libbpf is going to be deprecated. Call bpf_object_for_each_program to find a program in the section with a given name instead. Signed-off-by:
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Kui-Feng Lee authored
bpf_object__find_program_by_title is going to be deprecated. Replace use cases of bpf_object__find_program_by_title in samples/bpf/ with bpf_object__for_each_program. Signed-off-by:
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Kui-Feng Lee authored
bpf_object__find_program_by_title is going to be deprecated. Replace all use cases in tools/testing/selftests/bpf with bpf_object__find_program_by_name or bpf_object__for_each_program. Signed-off-by:
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Andrii Nakryiko authored
As libbpf now is able to automatically take care of RLIMIT_MEMLOCK increase (or skip it altogether on recent enough kernels), remove explicit setrlimit() invocations in bench, test_maps, test_verifier, and test_progs. Signed-off-by:
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Andrii Nakryiko authored
The need to increase RLIMIT_MEMLOCK to do anything useful with BPF is one of the first extremely frustrating gotchas that all new BPF users go through and in some cases have to learn it a very hard way. Luckily, starting with upstream Linux kernel version 5.11, BPF subsystem dropped the dependency on memlock and uses memcg-based memory accounting instead. Unfortunately, detecting memcg-based BPF memory accounting is far from trivial (as can be evidenced by this patch), so in practice most BPF applications still do unconditional RLIMIT_MEMLOCK increase. As we move towards libbpf 1.0, it would be good to allow users to forget about RLIMIT_MEMLOCK vs memcg and let libbpf do the sensible adjustment automatically. This patch paves the way forward in this matter. Libbpf will do feature detection of memcg-based accounting, and if detected, will do nothing. But if the kernel is too old, just like BCC, libbpf will automatically increase RLIMIT_MEMLOCK on behalf of user application ([0]). As this is technically a breaking change, during the transition period applications have to opt into libbpf 1.0 mode by setting LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK bit when calling libbpf_set_strict_mode(). Libbpf allows to control the exact amount of set RLIMIT_MEMLOCK limit with libbpf_set_memlock_rlim_max() API. Passing 0 will make libbpf do nothing with RLIMIT_MEMLOCK. libbpf_set_memlock_rlim_max() has to be called before the first bpf_prog_load(), bpf_btf_load(), or bpf_object__load() call, otherwise it has no effect and will return -EBUSY. [0] Closes: https://github.com/libbpf/libbpf/issues/369Signed-off-by:
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Andrii Nakryiko authored
strncpy() has a notoriously error-prone semantics which makes GCC complain about it a lot (and quite often completely completely falsely at that). Instead of pleasing GCC all the time (-Wno-stringop-truncation is unfortunately only supported by GCC, so it's a bit too messy to just enable it in Makefile), add libbpf-internal libbpf_strlcpy() helper which follows what FreeBSD's strlcpy() does and what most people would expect from strncpy(): copies up to N-1 first bytes from source string into destination string and ensures zero-termination afterwards. Replace all the relevant uses of strncpy/strncat/memcpy in libbpf with libbpf_strlcpy(). This also fixes the issue reported by Emmanuel Deloget in xsk.c where memcpy() could access source string beyond its end. Fixes: 2f6324a3 (libbpf: Support shared umems between queues and devices) Reported-by:
Emmanuel Deloget <emmanuel.deloget@eho.link> Signed-off-by:
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Andrii Nakryiko authored
In case of BPF_CORE_TYPE_ID_LOCAL we fill out target result explicitly. But targ_res itself isn't initialized in such a case, and subsequent call to bpf_core_patch_insn() might read uninitialized field (like fail_memsz_adjust in this case). So ensure that targ_res is zero-initialized for BPF_CORE_TYPE_ID_LOCAL case. This was reported by Coverity static analyzer. Signed-off-by:
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- 13 Dec, 2021 2 commits
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Maciej Fijalkowski authored
zero_copy_allocator has been removed back when Bjorn Topel introduced xsk_buff_pool. Remove references to it that were dangling in the tree. Signed-off-by:
Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by:
Magnus Karlsson <magnus.karlsson@intel.com> Link: https://lore.kernel.org/bpf/20211210171511.11574-1-maciej.fijalkowski@intel.com
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Grant Seltzer authored
This adds doc comments for the two bpf_program pinning functions, bpf_program__pin() and bpf_program__unpin() Signed-off-by:
Grant Seltzer <grantseltzer@gmail.com> Signed-off-by:
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