From 9975a54b3c9ecf029cbf5dd7a8c9701b1d74029e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 28 Jul 2017 17:05:25 +0200 Subject: [PATCH] bpf: fix bpf_prog_get_info_by_fd to dump correct xlated_prog_len bpf_prog_size(prog->len) is not the correct length we want to dump back to user space. The code in bpf_prog_get_info_by_fd() uses this to copy prog->insnsi to user space, but bpf_prog_size(prog->len) also includes the size of struct bpf_prog itself plus program instructions and is usually used either in context of accounting or for bpf_prog_alloc() et al, thus we copy out of bounds in bpf_prog_get_info_by_fd() potentially. Use the correct bpf_prog_insn_size() instead. Fixes: 1e2709769086 ("bpf: Add BPF_OBJ_GET_INFO_BY_FD") Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 84bb399..6c772ad 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1312,7 +1312,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, } ulen = info.xlated_prog_len; - info.xlated_prog_len = bpf_prog_size(prog->len); + info.xlated_prog_len = bpf_prog_insn_size(prog); if (info.xlated_prog_len && ulen) { uinsns = u64_to_user_ptr(info.xlated_prog_insns); ulen = min_t(u32, info.xlated_prog_len, ulen); -- 2.7.4