In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
xfs: bounds-check buffer log item’s dirty bitmap<\/p>\n
xlog_recover_do_reg_buffer() replays each dirty region described by a
\nbuffer log item’s bitmap into the buffer read for that item:<\/p>\n
\tmemcpy(xfs_buf_offset(bp, (uint)bit <ri_buf[i].iov_base,
\n\t\tnbits << XFS_BLF_SHIFT);<\/p>\n
The destination offset (bit\/nbits, from the logged dirty bitmap) and the
\nbuffer size (from the logged blf_len) are both attacker-controlled and
\notherwise unrelated, yet the only thing bounding the copy is an ASSERT(),
\nwhich compiles away on production kernels. A crafted image logging a
\nsmall blf_len together with a bitmap bit past the end of that buffer
\ndrives the memcpy() past the buffer's allocation, corrupting adjacent
\nkernel heap during mount-time log recovery. This is reachable by anyone
\nwho can get a crafted image mounted — the malicious-filesystem threat
\nmodel XFS already guards against elsewhere.<\/p>\n
Turn the ASSERT() into a real XFS_IS_CORRUPT() check that aborts recovery
\nof the buffer with -EFSCORRUPTED, consistent with the validate-and-fail
\nidiom already used in xlog_recover_do_inode_buffer() and
\nxfs_dquot_item_recover.c. xlog_recover_do_reg_buffer() therefore becomes
\nSTATIC int and its three callers propagate the error.<\/p>\n
Found and confirmed with KASAN on a CONFIG_XFS_DEBUG=n build: the crafted
\nimage trips a slab-out-of-bounds write before this change and fails
\nrecovery cleanly with -EFSCORRUPTED after it.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
xfs: bounds-check buffer log item’s dirty bitmap<\/p>\n
xlog_recover_do_reg_buffer() replays each dirty region described by a
\nbuffer log <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-11944","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/11944","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=11944"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11944"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11944"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}