This is a note to let you know that I've just added the patch titled net/x25: prevent a couple of overflows to the 5.4-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: net-x25-prevent-a-couple-of-overflows.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sun Dec 6 10:20:28 AM CET 2020 From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Tue, 1 Dec 2020 18:15:12 +0300 Subject: net/x25: prevent a couple of overflows From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> [ Upstream commit 6ee50c8e262a0f0693dad264c3c99e30e6442a56 ] The .x25_addr[] address comes from the user and is not necessarily NUL terminated. This leads to a couple problems. The first problem is that the strlen() in x25_bind() can read beyond the end of the buffer. The second problem is more subtle and could result in memory corruption. The call tree is: x25_connect() --> x25_write_internal() --> x25_addr_aton() The .x25_addr[] buffers are copied to the "addresses" buffer from x25_write_internal() so it will lead to stack corruption. Verify that the strings are NUL terminated and return -EINVAL if they are not. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: a9288525d2ae ("X25: Dont let x25_bind use addresses containing characters") Reported-by: "kiyin(尹亮)" <kiyin@xxxxxxxxxxx> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Acked-by: Martin Schiller <ms@xxxxxxxxxx> Link: https://lore.kernel.org/r/X8ZeAKm8FnFpN//B@mwanda Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/x25/af_x25.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -675,7 +675,8 @@ static int x25_bind(struct socket *sock, int len, i, rc = 0; if (addr_len != sizeof(struct sockaddr_x25) || - addr->sx25_family != AF_X25) { + addr->sx25_family != AF_X25 || + strnlen(addr->sx25_addr.x25_addr, X25_ADDR_LEN) == X25_ADDR_LEN) { rc = -EINVAL; goto out; } @@ -769,7 +770,8 @@ static int x25_connect(struct socket *so rc = -EINVAL; if (addr_len != sizeof(struct sockaddr_x25) || - addr->sx25_family != AF_X25) + addr->sx25_family != AF_X25 || + strnlen(addr->sx25_addr.x25_addr, X25_ADDR_LEN) == X25_ADDR_LEN) goto out; rc = -ENETUNREACH; Patches currently in stable-queue which might be from dan.carpenter@xxxxxxxxxx are queue-5.4/net-x25-prevent-a-couple-of-overflows.patch queue-5.4/chelsio-chtls-fix-a-double-free-in-chtls_setkey.patch