For SOCK_STREAM sockets, if user buffer size (len) is less than skb size (skb->len), the remaining data from skb will be lost after calling kfree_skb().

To fix this, move the statement for partial reading above skb deletion.

Found by InfoTeCS on behalf of Linux Verification Center (linuxtesting.org)

Fixes: 30a584d944fb ("[LLX]: SOCK_DGRAM interface fixes") Cc: stable@vger.kernel.org Signed-off-by: Ilia Gavrilov Ilia.Gavrilov@infotecs.ru --- net/llc/af_llc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 0259cde394ba..cc77ec5769d8 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -887,15 +887,15 @@ static int llc_ui_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, if (sk->sk_type != SOCK_STREAM) goto copy_uaddr;

+ /* Partial read */ + if (used + offset < skb_len) + continue; + if (!(flags & MSG_PEEK)) { skb_unlink(skb, &sk->sk_receive_queue); kfree_skb(skb); *seq = 0; } - - /* Partial read */ - if (used + offset < skb_len) - continue; } while (len > 0);

out: