From: Eric Dumazet edumazet@google.com
[ 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 syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Cc: Kees Cook keescook@chromium.org Cc: Willem de Bruijn willemdebruijn.kernel@gmail.com Reviewed-by: Kees Cook keescook@chromium.org 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 7188ca8d84693..952fde1aab2d6 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3792,28 +3792,30 @@ 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; }