From 8885bb0621f01a6c82be60a91e5fc0f6e2f71186 Mon Sep 17 00:00:00 2001 From: Peilin Ye Date: Wed, 22 Jul 2020 12:05:12 -0400 Subject: 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 Signed-off-by: David S. Miller --- net/ax25/af_ax25.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net') 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; } -- cgit