| From foo@baz Wed 29 Jul 2020 12:42:55 PM CEST |
| From: Peilin Ye <yepeilin.cs@gmail.com> |
| Date: Wed, 22 Jul 2020 12:05:12 -0400 |
| Subject: AX.25: Prevent out-of-bounds read in ax25_sendmsg() |
| |
| From: Peilin Ye <yepeilin.cs@gmail.com> |
| |
| [ Upstream commit 8885bb0621f01a6c82be60a91e5fc0f6e2f71186 ] |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/ax25/af_ax25.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/net/ax25/af_ax25.c |
| +++ b/net/ax25/af_ax25.c |
| @@ -1512,7 +1512,8 @@ static int ax25_sendmsg(struct socket *s |
| 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; |
| } |