From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 27 Jul 2017 19:02:46 +0000 (+0200)
Subject: bpf: don't indicate success when copy_from_user fails
X-Git-Tag: v4.13-rc4~29^2~14
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=89b096898a8450b0a5b97d521e000ae9f94f81f9;p=linux-2.6-block.git

bpf: don't indicate success when copy_from_user fails

err in bpf_prog_get_info_by_fd() still holds 0 at that time from prior
check_uarg_tail_zero() check. Explicitly return -EFAULT instead, so
user space can be notified of buggy behavior.

Fixes: 1e2709769086 ("bpf: Add BPF_OBJ_GET_INFO_BY_FD")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 045646da97cc..84bb39975ad4 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1289,7 +1289,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
 	info_len = min_t(u32, sizeof(info), info_len);
 
 	if (copy_from_user(&info, uinfo, info_len))
-		return err;
+		return -EFAULT;
 
 	info.type = prog->type;
 	info.id = prog->aux->id;