From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 27 Jul 2017 21:02:46 +0200
Subject: bpf: don't indicate success when copy_from_user fails
Patch-mainline: v4.13-rc4
Git-commit: 89b096898a8450b0a5b97d521e000ae9f94f81f9
References: bsc#1056787

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 kernel/bpf/syscall.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1284,7 +1284,7 @@ static int bpf_prog_get_info_by_fd(struc
 	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;