[PATCH AUTOSEL 6.8 08/30] af_packet: avoid a false positive warning in packet_setsockopt()
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DORMANTno replies
REVIEWED: 2 (1M)
From: Sasha Levin <sashal@kernel.org>
Date: 2024-05-27 14:14:33
Also in:
lkml, stable
Subsystem:
networking [general], packet sockets, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Willem de Bruijn, Linus Torvalds
Status: Reviewed.
2 review trailers.
From: Eric Dumazet <redacted> [ Upstream commit 86d43e2bf93ccac88ef71cee36a23282ebd9e427 ] Although the code is correct, the following line copy_from_sockptr(&req_u.req, optval, len)); triggers this warning : memcpy: detected field-spanning write (size 28) of single field "dst" at include/linux/sockptr.h:49 (size 16) Refactor the code to be more explicit. Reported-by: syzbot <redacted> Signed-off-by: Eric Dumazet <redacted> Cc: Kees Cook <redacted> Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Reviewed-by: Kees Cook <redacted> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/packet/af_packet.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index e6a8701a38dbe..59ca1e321db16 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c@@ -3800,28 +3800,30 @@ packet_setsockopt(struct socket *sock, int level, int optname, sockptr_t optval, case PACKET_TX_RING: { union tpacket_req_u req_u; - int len; + ret = -EINVAL; lock_sock(sk); switch (po->tp_version) { case TPACKET_V1: case TPACKET_V2: - len = sizeof(req_u.req); + if (optlen < sizeof(req_u.req)) + break; + ret = copy_from_sockptr(&req_u.req, optval, + sizeof(req_u.req)) ? + -EINVAL : 0; break; case TPACKET_V3: default: - len = sizeof(req_u.req3); + if (optlen < sizeof(req_u.req3)) + break; + ret = copy_from_sockptr(&req_u.req3, optval, + sizeof(req_u.req3)) ? + -EINVAL : 0; break; } - if (optlen < len) { - ret = -EINVAL; - } else { - if (copy_from_sockptr(&req_u.req, optval, len)) - ret = -EFAULT; - else - ret = packet_set_ring(sk, &req_u, 0, - optname == PACKET_TX_RING); - } + if (!ret) + ret = packet_set_ring(sk, &req_u, 0, + optname == PACKET_TX_RING); release_sock(sk); return ret; }
--
2.43.0