This is a note to let you know that I've just added the patch titled l2tp: fix incorrect parameter validation in the pppol2tp_getsockopt() function to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: l2tp-fix-incorrect-parameter-validation-in-the-pppol.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 8a5266dfa076d9cc6cbbcf8430faaea3ad12227d Author: Gavrilov Ilia <Ilia.Gavrilov@xxxxxxxxxxx> Date: Thu Mar 7 14:23:50 2024 +0000 l2tp: fix incorrect parameter validation in the pppol2tp_getsockopt() function [ Upstream commit 955e9876ba4ee26eeaab1b13517f5b2c88e73d55 ] The 'len' variable can't be negative when assigned the result of 'min_t' because all 'min_t' parameters are cast to unsigned int, and then the minimum one is chosen. To fix the logic, check 'len' as read from 'optlen', where the types of relevant variables are (signed) int. Fixes: 3557baabf280 ("[L2TP]: PPP over L2TP driver core") Reviewed-by: Tom Parkin <tparkin@xxxxxxxxxxx> Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@xxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index c0956781665e1..3ed3b85f30b6e 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -1380,11 +1380,11 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname, if (get_user(len, optlen)) return -EFAULT; - len = min_t(unsigned int, len, sizeof(int)); - if (len < 0) return -EINVAL; + len = min_t(unsigned int, len, sizeof(int)); + err = -ENOTCONN; if (sk->sk_user_data == NULL) goto end;