In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
sctp: stop processing a packet once its association is deleted<\/p>\n
sctp_endpoint_bh_rcv() looks the association up only when chunk->asoc is
\nNULL, and caches the result in chunk->asoc and chunk->transport without
\ntaking a reference.<\/p>\n
A packet that matches no association is handed to the endpoint, so a peer
\ncan bundle COOKIE ECHO, SHUTDOWN and SHUTDOWN ACK in one packet. The
\nCOOKIE ECHO creates the association, the SHUTDOWN chunk caches it, and
\nwith the outqueue empty the SHUTDOWN ACK reaches sctp_sf_do_9_2_final(),
\nso the association and its transports are freed.<\/p>\n
The endpoint loop has no counterpart to the asoc->base.dead check in
\nsctp_assoc_bh_rcv(). The next chunk writes to last_time_heard in the freed
\ntransport and is then passed to sctp_do_sm() with the freed association.
\nThe transport is freed through RCU, so this needs the packet to come off
\nthe socket backlog, where the loop runs in task context.<\/p>\n
The endpoint loop cannot do the same check: it holds no reference on the
\nassociation, so reading asoc->base.dead would itself be a use-after-free.
\nMark the packet for discard in the command interpreter, just before it
\ndeletes the association. That is also before sctp_inq_free() releases the
\nchunk on the association receive path.<\/p>\n
sctp_sf_do_5_2_4_dupcook() issues SCTP_CMD_DELETE_TCB for the temporary
\nassociation, while the one the packet belongs to stays alive. A restarting
\npeer can bundle DATA behind its COOKIE ECHO, so compare against
\nchunk->asoc and leave that case alone.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
sctp: stop processing a packet once its association is deleted<\/p>\n
sctp_endpoint_bh_rcv() looks the association up only when chunk->as<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21401","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21401","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21401"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21401"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21401"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}