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authorPeilin Ye <yepeilin.cs@gmail.com>2020-07-22 11:19:01 -0400
committerDavid S. Miller <davem@davemloft.net>2020-07-22 17:56:40 -0700
commit2f2a7ffad5c6cbf3d438e813cfdc88230e185ba6 (patch)
treedb2289e67686fae52fea86f60b8d80e0dcdb3f36 /net/ax25/af_ax25.c
parent26cb7085c8984e5b71d65c374a135134ed8cabb3 (diff)
AX.25: Fix out-of-bounds read in ax25_connect()
Checks on `addr_len` and `fsa->fsa_ax25.sax25_ndigis` are insufficient. ax25_connect() can go out of bounds when `fsa->fsa_ax25.sax25_ndigis` equals to 7 or 8. Fix it. This issue has been reported as a KMSAN uninit-value bug, because in such a case, ax25_connect() reaches into the uninitialized portion of the `struct sockaddr_storage` statically allocated in __sys_connect(). It is safe to remove `fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS` because `addr_len` is guaranteed to be less than or equal to `sizeof(struct full_sockaddr_ax25)`. Reported-by: syzbot+c82752228ed975b0a623@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=55ef9d629f3b3d7d70b69558015b63b48d01af66 Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ax25/af_ax25.c')
-rw-r--r--net/ax25/af_ax25.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index fd91cd34f25e..ef5bf116157a 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1187,7 +1187,9 @@ static int __must_check ax25_connect(struct socket *sock,
if (addr_len > sizeof(struct sockaddr_ax25) &&
fsa->fsa_ax25.sax25_ndigis != 0) {
/* Valid number of digipeaters ? */
- if (fsa->fsa_ax25.sax25_ndigis < 1 || fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS) {
+ if (fsa->fsa_ax25.sax25_ndigis < 1 ||
+ addr_len < sizeof(struct sockaddr_ax25) +
+ sizeof(ax25_address) * fsa->fsa_ax25.sax25_ndigis) {
err = -EINVAL;
goto out_release;
}