In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
afs: Fix UAF when sending a message<\/p>\n
In afs_make_call(), there’s a race with async call reception and
\ndestruction. If a call is dispatched that doesn’t have call->write_iter
\nset (used to specify the data content for FS.StoreData), then the first
\nrxrpc_kernel_send_data() will not set MSG_MORE in the msghdr.<\/p>\n
Once rxrpc_send_data() queues the last request packet, the response could
\ncome in at any time and cause the call to be completed and put. However,
\nafs_make_call() will look at the call again to see it ->write_iter should
\nbe handled – something it’s only allowed to do if it has its own ref on the
\ncall. Whilst this is the case for synchronous calls, it isn’t true for
\nasync calls such as FS.FetchData.<\/p>\n
There’s also a potential UAF in afs_make_call() in the event that an
\nasynchronous call is being sent, but the call fails in some way (e.g. it
\ngets aborted from the server). The problem there is that afs_make_call()
\ntries to abort a call if the rxrpc send fails, but the asynchronous
\nnotification from rxrpc may have caused the afs_call to be torn down.<\/p>\n
generic\/650 plays games with randomly taking CPUs offline, and can
\ninterject a significant delay such that the call is deallocated before
\nafs_make_call() gets to check call->write_iter – and a UAF ensues (caught
\nby KASAN).<\/p>\n
BUG: KASAN: slab-use-after-free in afs_make_call+0x1c90\/0x2210 [kafs]
\n Read of size 8 at addr ffff888035e050e8 by task fsstress\/1409<\/p>\n
Fix this by making afs_make_op_call() give the op->call its own ref rather
\nthan transferring the caller’s ref to it and then dropping the ref when
\nafs_make_call() returns.<\/p>\n
This also means that the afs_make_call() func never loses its ref on the
\ncall now.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
afs: Fix UAF when sending a message<\/p>\n
In afs_make_call(), there’s a race with async call reception and
\ndestruction. If a call is di<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-7498","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/7498","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=7498"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7498"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7498"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}