From: Ming-Hung Tsai <mtsai@redhat.com> mainline inclusion from mainline-v6.13-rc7 commit f2893c0804d86230ffb8f1c8703fdbb18648abc8 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBIQYC CVE: CVE-2024-57929 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When dm_bm_read_lock() fails due to locking or checksum errors, it releases the faulty block implicitly while leaving an invalid output pointer behind. The caller of dm_bm_read_lock() should not operate on this invalid dm_block pointer, or it will lead to undefined result. For example, the dm_array_cursor incorrectly caches the invalid pointer on reading a faulty array block, causing a double release in dm_array_cursor_end(), then hitting the BUG_ON in dm-bufio cache_put(). Reproduce steps: 1. initialize a cache device dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc $262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. wipe the second array block offline dmsteup remove cache cmeta cdata corig mapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \ 2>/dev/null | hexdump -e '1/8 "%u\n"') ablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \ 2>/dev/null | hexdump -e '1/8 "%u\n"') dd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock 3. try reopen the cache device dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc $262144" dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" Kernel logs: (snip) device-mapper: array: array_block_check failed: blocknr 0 != wanted 10 device-mapper: block manager: array validator check failed for block 10 device-mapper: array: get_ablock failed device-mapper: cache metadata: dm_array_cursor_next for mapping failed ------------[ cut here ]------------ kernel BUG at drivers/md/dm-bufio.c:638! Fix by setting the cached block pointer to NULL on errors. In addition to the reproducer described above, this fix can be verified using the "array_cursor/damaged" test in dm-unit: dm-unit run /pdata/array_cursor/damaged --kernel-dir <KERNEL_DIR> Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com> Fixes: fdd1315aa5f0 ("dm array: introduce cursor api") Reviewed-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com> --- drivers/md/persistent-data/dm-array.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/md/persistent-data/dm-array.c b/drivers/md/persistent-data/dm-array.c index 185dc60360b5..849eb1b97c43 100644 --- a/drivers/md/persistent-data/dm-array.c +++ b/drivers/md/persistent-data/dm-array.c @@ -907,23 +907,27 @@ static int load_ablock(struct dm_array_cursor *c) if (c->block) unlock_ablock(c->info, c->block); - c->block = NULL; - c->ab = NULL; c->index = 0; r = dm_btree_cursor_get_value(&c->cursor, &key, &value_le); if (r) { DMERR("dm_btree_cursor_get_value failed"); - dm_btree_cursor_end(&c->cursor); + goto out; } else { r = get_ablock(c->info, le64_to_cpu(value_le), &c->block, &c->ab); if (r) { DMERR("get_ablock failed"); - dm_btree_cursor_end(&c->cursor); + goto out; } } + return 0; + +out: + dm_btree_cursor_end(&c->cursor); + c->block = NULL; + c->ab = NULL; return r; } -- 2.46.1