In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
RDMA\/rxe: validate access flags before swapping the MR’s PD<\/p>\n
rxe_rereg_user_mr() reassigns mr->ibmr.pd first and only then
\nvalidates the IB_MR_REREG_ACCESS argument:<\/p>\n
\tif (flags & IB_MR_REREG_PD) {
\n\t\trxe_put(old_pd);
\n\t\trxe_get(pd);
\n\t\tmr->ibmr.pd = ibpd;
\n\t}<\/p>\n
\tif (flags & IB_MR_REREG_ACCESS) {
\n\t\tif (access & ~RXE_ACCESS_SUPPORTED_MR)
\n\t\t\treturn ERR_PTR(-EOPNOTSUPP);
\n\t\tmr->access = access;
\n\t}<\/p>\n
Both flags pass the entry check because RXE_MR_REREG_SUPPORTED is
\nIB_MR_REREG_PD | IB_MR_REREG_ACCESS, so a caller can reach the access
\ncheck with mr->ibmr.pd already reassigned.<\/p>\n
mr->ibmr.pd is owned by the core, which adjusts pd->usecnt only on the
\nsuccess path: ib_uverbs_rereg_mr() jumps to put_new_uobj on a driver error
\nwithout undoing the reassignment, so mr->pd == new_pd while the usecnts
\nstill charge the MR to orig_pd. ib_dereg_mr_user() then decrements
\nnew_pd, whose count can reach zero while a memory window still references
\nit; uverbs_free_pd() frees the PD on that count alone and rxe_mw_cleanup()
\nwrites to freed memory:<\/p>\n
BUG: KASAN: slab-use-after-free in __rxe_put+0x31\/0xa0
\n Write of size 4 at addr ffff8881301dd690 by task rxe_poc\/591
\n __rxe_put+0x31\/0xa0
\n rxe_mw_cleanup+0x42\/0x200
\n __rxe_cleanup+0x115\/0x370
\n rxe_dealloc_mw+0x4c\/0x80
\n Allocated by task 591:
\n ib_uverbs_alloc_pd+0x258\/0x540
\n Freed by task 591:
\n ib_dealloc_pd_user+0x174\/0x210
\n uverbs_free_pd+0x8d\/0xc0
\n ib_uverbs_dealloc_pd+0x18e\/0x1d0<\/p>\n
Validate the access flags before mutating any state so the callback either
\napplies every requested change or none.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
RDMA\/rxe: validate access flags before swapping the MR’s PD<\/p>\n
rxe_rereg_user_mr() reassigns mr->ibmr.pd first and only then
\nvalidate<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-33435","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/33435","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=33435"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=33435"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=33435"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}