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authorPeilin Ye <yepeilin.cs@gmail.com>2020-07-22 12:05:12 -0400
committerDavid S. Miller <davem@davemloft.net>2020-07-22 18:06:49 -0700
commit8885bb0621f01a6c82be60a91e5fc0f6e2f71186 (patch)
treec91120c4f5a39c568f95e4f48a9098cb285c2678
parentf659173364c64d3276b8aba62368e7e732fab309 (diff)
AX.25: Prevent out-of-bounds read in ax25_sendmsg()
Checks on `addr_len` and `usax->sax25_ndigis` are insufficient. ax25_sendmsg() can go out of bounds when `usax->sax25_ndigis` equals to 7 or 8. Fix it. It is safe to remove `usax->sax25_ndigis > AX25_MAX_DIGIS`, since `addr_len` is guaranteed to be less than or equal to `sizeof(struct full_sockaddr_ax25)` Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ax25/af_ax25.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index ef5bf116157a..0862fe49d434 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1509,7 +1509,8 @@ static int ax25_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)usax;
/* Valid number of digipeaters ? */
- if (usax->sax25_ndigis < 1 || usax->sax25_ndigis > AX25_MAX_DIGIS) {
+ if (usax->sax25_ndigis < 1 || addr_len < sizeof(struct sockaddr_ax25) +
+ sizeof(ax25_address) * usax->sax25_ndigis) {
err = -EINVAL;
goto out;
}