In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fscrypt: Avoid dynamic allocation in fscrypt_get_devices()<\/p>\n
When a blk_crypto_key starts being used or is evicted, fs\/crypto\/ calls
\nfscrypt_get_devices() to get the filesystem’s list of block devices,
\nthen iterates over them and calls blk_crypto_config_supported(),
\nblk_crypto_start_using_key(), or blk_crypto_evict_key() on each one.<\/p>\n
Currently, the block device pointers are placed in a dynamically
\nallocated array. This dynamic allocation is problematic because:<\/p>\n
– It can fail, especially at the fscrypt_destroy_inline_crypt_key() call
\n site when it’s invoked for inode eviction under direct reclaim.<\/p>\n
– fscrypt_destroy_inline_crypt_key() doesn’t handle the failure. It
\n just zeroizes and frees the blk_crypto_key without calling
\n blk_crypto_evict_key(). That causes a use-after-free.<\/p>\n
For now, let’s fix this in the straightforward and easily-backportable
\nway by switching to an on-stack array. Currently the fscrypt
\nmulti-device functionality is used only by f2fs, which has a hardcoded
\nlimit of 8 block devices. An on-stack array works fine for that.<\/p>\n
(Of course, this solution won’t scale up to large number of block
\ndevices. For that we’d need a different solution, like moving the block
\ndevice iteration into the filesystem. Or in the case of btrfs, which
\nwill only support blk-crypto-fallback, we should make it just call
\nblk-crypto-fallback directly, so the block devices won’t be needed.)<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fscrypt: Avoid dynamic allocation in fscrypt_get_devices()<\/p>\n
When a blk_crypto_key starts being used or is evicted, fs\/crypto\/ calls<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-5353","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/5353","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=5353"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5353"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5353"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}