| From 965ed319df7e6b4e9d85c916bcb8f7f05fc0cdda Mon Sep 17 00:00:00 2001 |
| From: Daniel Borkmann <dborkman@redhat.com> |
| Date: Sat, 7 Sep 2013 20:51:21 +0200 |
| Subject: net: sctp: fix smatch warning in sctp_send_asconf_del_ip |
| |
| From: Daniel Borkmann <dborkman@redhat.com> |
| |
| [ Upstream commit 88362ad8f9a6cea787420b57cc27ccacef000dbe ] |
| |
| This was originally reported in [1] and posted by Neil Horman [2], he said: |
| |
| Fix up a missed null pointer check in the asconf code. If we don't find |
| a local address, but we pass in an address length of more than 1, we may |
| dereference a NULL laddr pointer. Currently this can't happen, as the only |
| users of the function pass in the value 1 as the addrcnt parameter, but |
| its not hot path, and it doesn't hurt to check for NULL should that ever |
| be the case. |
| |
| The callpath from sctp_asconf_mgmt() looks okay. But this could be triggered |
| from sctp_setsockopt_bindx() call with SCTP_BINDX_REM_ADDR and addrcnt > 1 |
| while passing all possible addresses from the bind list to SCTP_BINDX_REM_ADDR |
| so that we do *not* find a single address in the association's bind address |
| list that is not in the packed array of addresses. If this happens when we |
| have an established association with ASCONF-capable peers, then we could get |
| a NULL pointer dereference as we only check for laddr == NULL && addrcnt == 1 |
| and call later sctp_make_asconf_update_ip() with NULL laddr. |
| |
| BUT: this actually won't happen as sctp_bindx_rem() will catch such a case |
| and return with an error earlier. As this is incredably unintuitive and error |
| prone, add a check to catch at least future bugs here. As Neil says, its not |
| hot path. Introduced by 8a07eb0a5 ("sctp: Add ASCONF operation on the |
| single-homed host"). |
| |
| [1] http://www.spinics.net/lists/linux-sctp/msg02132.html |
| [2] http://www.spinics.net/lists/linux-sctp/msg02133.html |
| |
| Reported-by: Dan Carpenter <dan.carpenter@oracle.com> |
| Signed-off-by: Neil Horman <nhorman@tuxdriver.com> |
| Signed-off-by: Daniel Borkmann <dborkman@redhat.com> |
| Cc: Michio Honda <micchie@sfc.wide.ad.jp> |
| Acked-By: Neil Horman <nhorman@tuxdriver.com> |
| Acked-by: Vlad Yasevich <vyasevich@gmail.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sctp/socket.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/net/sctp/socket.c |
| +++ b/net/sctp/socket.c |
| @@ -812,6 +812,9 @@ static int sctp_send_asconf_del_ip(struc |
| goto skip_mkasconf; |
| } |
| |
| + if (laddr == NULL) |
| + return -EINVAL; |
| + |
| /* We do not need RCU protection throughout this loop |
| * because this is done under a socket lock from the |
| * setsockopt call. |