From 8ca990ce0d402d5aaf05f7a33ff025fcbcbb5f93 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 29 May 2019 10:36:03 -0700 Subject: [PATCH] libbpf: fix detection of corrupted BPF instructions section Ensure that size of a section w/ BPF instruction is exactly a multiple of BPF instruction size. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 30cb08e..c985a79 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -349,8 +349,11 @@ static int bpf_program__init(void *data, size_t size, char *section_name, int idx, struct bpf_program *prog) { - if (size < sizeof(struct bpf_insn)) { - pr_warning("corrupted section '%s'\n", section_name); + const size_t bpf_insn_sz = sizeof(struct bpf_insn); + + if (size == 0 || size % bpf_insn_sz) { + pr_warning("corrupted section '%s', size: %zu\n", + section_name, size); return -EINVAL; } @@ -376,9 +379,8 @@ bpf_program__init(void *data, size_t size, char *section_name, int idx, section_name); goto errout; } - prog->insns_cnt = size / sizeof(struct bpf_insn); - memcpy(prog->insns, data, - prog->insns_cnt * sizeof(struct bpf_insn)); + prog->insns_cnt = size / bpf_insn_sz; + memcpy(prog->insns, data, size); prog->idx = idx; prog->instances.fds = NULL; prog->instances.nr = -1; -- 2.7.4