From: Dan Carpenter dan.carpenter@oracle.com
[ 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@tencent.com Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Acked-by: Martin Schiller ms@dev.tdt.de Link: https://lore.kernel.org/r/X8ZeAKm8FnFpN//B@mwanda Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/x25/af_x25.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index b3db0b0a52f5..f43d037ea852 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -680,7 +680,8 @@ static int x25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 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; } @@ -774,7 +775,8 @@ static int x25_connect(struct socket *sock, struct sockaddr *uaddr,
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;