5.4-stable review patch. If anyone has any objections, please let me know.
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From: Ilia Gavrilov Ilia.Gavrilov@infotecs.ru
commit 239af1970bcb039a1551d2c438d113df0010c149 upstream.
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 Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/llc/af_llc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -885,15 +885,15 @@ static int llc_ui_recvmsg(struct socket 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: