From: Daniel Borkmann Date: Sat, 7 Sep 2013 18:51:21 +0000 (+0200) Subject: net: sctp: fix smatch warning in sctp_send_asconf_del_ip X-Git-Tag: v3.2.52~49 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=836f6cb46716e36cb8d31a402c6661af5c895135;p=pandora-kernel.git net: sctp: fix smatch warning in sctp_send_asconf_del_ip [ 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 Signed-off-by: Neil Horman Signed-off-by: Daniel Borkmann Cc: Michio Honda Acked-By: Neil Horman Acked-by: Vlad Yasevich Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed