From 1654a0e4d576d9e43fbb10ccf6a1b307c5c18566 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Tue, 2 Sep 2025 11:17:12 -0700 Subject: perf bpf-utils: Constify bpil_array_desc The array's contents is a compile time constant. Constify to make the code more intention revealing and avoid unintended errors. Reviewed-by: Namhyung Kim Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250902181713.309797-3-irogers@google.com Signed-off-by: Namhyung Kim --- tools/perf/util/bpf-utils.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) (limited to 'tools/perf/util/bpf-utils.c') diff --git a/tools/perf/util/bpf-utils.c b/tools/perf/util/bpf-utils.c index 80b1d2b3729b..64a558344696 100644 --- a/tools/perf/util/bpf-utils.c +++ b/tools/perf/util/bpf-utils.c @@ -20,7 +20,7 @@ struct bpil_array_desc { */ }; -static struct bpil_array_desc bpil_array_desc[] = { +static const struct bpil_array_desc bpil_array_desc[] = { [PERF_BPIL_JITED_INSNS] = { offsetof(struct bpf_prog_info, jited_prog_insns), offsetof(struct bpf_prog_info, jited_prog_len), @@ -129,12 +129,10 @@ get_bpf_prog_info_linear(int fd, __u64 arrays) /* step 2: calculate total size of all arrays */ for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) { + const struct bpil_array_desc *desc = &bpil_array_desc[i]; bool include_array = (arrays & (1UL << i)) > 0; - struct bpil_array_desc *desc; __u32 count, size; - desc = bpil_array_desc + i; - /* kernel is too old to support this field */ if (info_len < desc->array_offset + sizeof(__u32) || info_len < desc->count_offset + sizeof(__u32) || @@ -163,13 +161,12 @@ get_bpf_prog_info_linear(int fd, __u64 arrays) ptr = info_linear->data; for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) { - struct bpil_array_desc *desc; + const struct bpil_array_desc *desc = &bpil_array_desc[i]; __u32 count, size; if ((arrays & (1UL << i)) == 0) continue; - desc = bpil_array_desc + i; count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); bpf_prog_info_set_offset_u32(&info_linear->info, @@ -192,13 +189,12 @@ get_bpf_prog_info_linear(int fd, __u64 arrays) /* step 6: verify the data */ for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) { - struct bpil_array_desc *desc; + const struct bpil_array_desc *desc = &bpil_array_desc[i]; __u32 v1, v2; if ((arrays & (1UL << i)) == 0) continue; - desc = bpil_array_desc + i; v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset); v2 = bpf_prog_info_read_offset_u32(&info_linear->info, desc->count_offset); @@ -224,13 +220,12 @@ void bpil_addr_to_offs(struct perf_bpil *info_linear) int i; for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) { - struct bpil_array_desc *desc; + const struct bpil_array_desc *desc = &bpil_array_desc[i]; __u64 addr, offs; if ((info_linear->arrays & (1UL << i)) == 0) continue; - desc = bpil_array_desc + i; addr = bpf_prog_info_read_offset_u64(&info_linear->info, desc->array_offset); offs = addr - ptr_to_u64(info_linear->data); @@ -244,13 +239,12 @@ void bpil_offs_to_addr(struct perf_bpil *info_linear) int i; for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) { - struct bpil_array_desc *desc; + const struct bpil_array_desc *desc = &bpil_array_desc[i]; __u64 addr, offs; if ((info_linear->arrays & (1UL << i)) == 0) continue; - desc = bpil_array_desc + i; offs = bpf_prog_info_read_offset_u64(&info_linear->info, desc->array_offset); addr = offs + ptr_to_u64(info_linear->data); -- cgit v1.2.3 From 01be43f2a0eaeed83e94dee054742f37625c86d9 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Tue, 2 Sep 2025 11:17:13 -0700 Subject: perf bpf-utils: Harden get_bpf_prog_info_linear In get_bpf_prog_info_linear two calls to bpf_obj_get_info_by_fd are made, the first to compute memory requirements for a struct perf_bpil and the second to fill it in. Previously the code would warn when the second call didn't match the first. Such races can be common place in things like perf test, whose perf trace tests will frequently load BPF programs. Rather than a debug message, return actual errors for this case. Out of paranoia also validate the read bpf_prog_info array value. Change the type of ptr to avoid mismatched pointer type compiler warnings. Add some additional debug print outs and sanity asserts. Closes: https://lore.kernel.org/lkml/CAP-5=fWJQcmUOP7MuCA2ihKnDAHUCOBLkQFEkQES-1ZZTrgf8Q@mail.gmail.com/ Fixes: 6ac22d036f86 ("perf bpf: Pull in bpf_program__get_prog_info_linear()") Reviewed-by: Namhyung Kim Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250902181713.309797-4-irogers@google.com Signed-off-by: Namhyung Kim --- tools/perf/util/bpf-utils.c | 43 +++++++++++++++++++++++++++++++++---------- 1 file changed, 33 insertions(+), 10 deletions(-) (limited to 'tools/perf/util/bpf-utils.c') diff --git a/tools/perf/util/bpf-utils.c b/tools/perf/util/bpf-utils.c index 64a558344696..5a66dc8594aa 100644 --- a/tools/perf/util/bpf-utils.c +++ b/tools/perf/util/bpf-utils.c @@ -115,7 +115,7 @@ get_bpf_prog_info_linear(int fd, __u64 arrays) __u32 info_len = sizeof(info); __u32 data_len = 0; int i, err; - void *ptr; + __u8 *ptr; if (arrays >> PERF_BPIL_LAST_ARRAY) return ERR_PTR(-EINVAL); @@ -126,6 +126,8 @@ get_bpf_prog_info_linear(int fd, __u64 arrays) pr_debug("can't get prog info: %s", strerror(errno)); return ERR_PTR(-EFAULT); } + if (info.type >= __MAX_BPF_PROG_TYPE) + pr_debug("%s:%d: unexpected program type %u\n", __func__, __LINE__, info.type); /* step 2: calculate total size of all arrays */ for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) { @@ -173,6 +175,8 @@ get_bpf_prog_info_linear(int fd, __u64 arrays) desc->count_offset, count); bpf_prog_info_set_offset_u32(&info_linear->info, desc->size_offset, size); + assert(ptr >= info_linear->data); + assert(ptr < &info_linear->data[data_len]); bpf_prog_info_set_offset_u64(&info_linear->info, desc->array_offset, ptr_to_u64(ptr)); @@ -186,26 +190,45 @@ get_bpf_prog_info_linear(int fd, __u64 arrays) free(info_linear); return ERR_PTR(-EFAULT); } + if (info_linear->info.type >= __MAX_BPF_PROG_TYPE) { + pr_debug("%s:%d: unexpected program type %u\n", + __func__, __LINE__, info_linear->info.type); + } /* step 6: verify the data */ + ptr = info_linear->data; for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) { const struct bpil_array_desc *desc = &bpil_array_desc[i]; - __u32 v1, v2; + __u32 count1, count2, size1, size2; + __u64 ptr2; if ((arrays & (1UL << i)) == 0) continue; - v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset); - v2 = bpf_prog_info_read_offset_u32(&info_linear->info, + count1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset); + count2 = bpf_prog_info_read_offset_u32(&info_linear->info, desc->count_offset); - if (v1 != v2) - pr_warning("%s: mismatch in element count\n", __func__); + if (count1 != count2) { + pr_warning("%s: mismatch in element count %u vs %u\n", __func__, count1, count2); + free(info_linear); + return ERR_PTR(-ERANGE); + } - v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset); - v2 = bpf_prog_info_read_offset_u32(&info_linear->info, + size1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset); + size2 = bpf_prog_info_read_offset_u32(&info_linear->info, desc->size_offset); - if (v1 != v2) - pr_warning("%s: mismatch in rec size\n", __func__); + if (size1 != size2) { + pr_warning("%s: mismatch in rec size %u vs %u\n", __func__, size1, size2); + free(info_linear); + return ERR_PTR(-ERANGE); + } + ptr2 = bpf_prog_info_read_offset_u64(&info_linear->info, desc->array_offset); + if (ptr_to_u64(ptr) != ptr2) { + pr_warning("%s: mismatch in array %p vs %llx\n", __func__, ptr, ptr2); + free(info_linear); + return ERR_PTR(-ERANGE); + } + ptr += roundup(count1 * size1, sizeof(__u64)); } /* step 7: update info_len and data_len */ -- cgit v1.2.3