From e20d3a055a457a10a4c748ce5b7c2ed3173a1324 Mon Sep 17 00:00:00 2001 From: Johannes Krude Date: Wed, 12 Feb 2020 20:32:27 +0100 Subject: [PATCH] bpf, offload: Replace bitwise AND by logical AND in bpf_prog_offload_info_fill This if guards whether user-space wants a copy of the offload-jited bytecode and whether this bytecode exists. By erroneously doing a bitwise AND instead of a logical AND on user- and kernel-space buffer-size can lead to no data being copied to user-space especially when user-space size is a power of two and bigger then the kernel-space buffer. Fixes: fcfb126defda ("bpf: add new jited info fields in bpf_dev_offload and bpf_prog_info") Signed-off-by: Johannes Krude Signed-off-by: Daniel Borkmann Acked-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/20200212193227.GA3769@phlox.h.transitiv.net --- kernel/bpf/offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c index 2c5dc6541ece..bd09290e3648 100644 --- a/kernel/bpf/offload.c +++ b/kernel/bpf/offload.c @@ -321,7 +321,7 @@ int bpf_prog_offload_info_fill(struct bpf_prog_info *info, ulen = info->jited_prog_len; info->jited_prog_len = aux->offload->jited_len; - if (info->jited_prog_len & ulen) { + if (info->jited_prog_len && ulen) { uinsns = u64_to_user_ptr(info->jited_prog_insns); ulen = min_t(u32, info->jited_prog_len, ulen); if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {