commit 4538a287bdf5d0f9a379c678e5262b9f5783f547 upstream.
array_block_check() can only compare the header against itself, so a block
with value_size 4 and max_entries 1018 is internally consistent and passes.
dm-cache keeps two arrays -- mappings at 8 bytes and hints at 4 -- and the
roots for both live in the superblock. Point the mappings root at a hint
block and __load_mappings() walks it through an info whose value size is 8,
so element_at() strides 8 bytes over 4-byte entries and reaches offset 8160
of a 4096-byte block.
get_ablock() and __shadow_ablock() are the two places that hold the block
and the caller at once. Reject there when the two value sizes disagree.
Arrays only ever read their own blocks, so this fires on crafted metadata
only.
Fixes: 6513c29f44f2 ("dm persistent data: add transactional array")
Suggested-by: Ming-Hung Tsai <mtsai@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Reviewed-by: Ming-Hung Tsai <mtsai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2965787723084835b18dfe993cd450ebf5bd4540 upstream.
array_block_check() validates blocknr and csum and nothing else, while
node_check(), next to it, has bounded the structural fields since both
were written. dm_array_cursor_next() takes its loop bound from the
on-disk nr_entries and element_at() is unguarded pointer arithmetic, so
a count larger than the block holds keeps the cursor in one block while
the index grows past it and the read walks off the dm-bufio buffer --
dm_cache_load_mappings() drives it once per cache block at activation.
Check the header against itself: reject a zero value_size, require
max_entries to equal calc_max_entries() for that value_size and block
size, and require nr_entries to fit. Equality rather than an upper bound,
since a count below the real capacity trips BUG_ON() in fill_ablock() and
trim_ablock(). Metadata dm-array writes satisfies all three.
Fixes: 6513c29f44f2 ("dm persistent data: add transactional array")
Suggested-by: Ming-Hung Tsai <mtsai@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Reviewed-by: Ming-Hung Tsai <mtsai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 09a65adc7d8bbfce06392cb6d375468e2728ead5 upstream.
There's a bug in dm-thin in the function rebalance_children. If the
internal btree node has one entry, the code tries to copy all btree
entries from the node's child to the node itself and then decrement the
child's reference count.
If the child node is shared (it has reference count > 1), we won't free
it, so there would be two pointers to each of the grandchildren nodes.
But the reference counts of the grandchildren is not increased, thus the
reference count doesn't match the number of pointers that point to the
grandchildren. This results in "device mapper: space map common: unable
to decrement block" errors.
Fix this bug by incrementing reference counts on the grandchildren if the
btree node is shared.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 3241b1d3e0aa ("dm: add persistent data library")
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 0bb1968da2737ba68fd63857d1af2b301a18d3bf ]
dm_array_cursor_skip() seeks to the target position by loading array
blocks iteratively until the specified number of entries to skip is
reached. When seeking across block boundaries, it uses
dm_array_cursor_next() to step into the next block.
dm_array_cursor_skip() must first move the cursor index to the end
of the current block; otherwise, the cursor position could incorrectly
remain in the same block, causing the actual number of skipped entries
to be much smaller than expected.
This bug affects cache resizing in v2 metadata and could lead to data
loss if the fast device is shrunk during the first-time resume. For
example:
1. create a cache metadata consists of 32768 blocks, with a dirty block
assigned to the second bitmap block. cache_restore v1.0 is required.
cat <<EOF >> cmeta.xml
<superblock uuid="" block_size="64" nr_cache_blocks="32768" \
policy="smq" hint_width="4">
<mappings>
<mapping cache_block="32767" origin_block="0" dirty="true"/>
</mappings>
</superblock>
EOF
dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
cache_restore -i cmeta.xml -o /dev/mapper/cmeta --metadata-version=2
2. bring up the cache while attempt to discard all the blocks belonging
to the second bitmap block (block# 32576 to 32767). The last command
is expected to fail, but it actually succeeds.
dmsetup create cdata --table "0 2084864 linear /dev/sdc 8192"
dmsetup create corig --table "0 65536 linear /dev/sdc 2105344"
dmsetup create cache --table "0 65536 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 64 2 metadata2 writeback smq \
2 migration_threshold 0"
In addition to the reproducer described above, this fix can be
verified using the "array_cursor/skip" tests in dm-unit:
dm-unit run /pdata/array_cursor/skip/ --kernel-dir <KERNEL_DIR>
Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Fixes: 9b696229aa7d ("dm persistent data: add cursor skip functions to the cursor APIs")
Reviewed-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 626f128ee9c4133b1cfce4be2b34a1508949370e ]
The cached block pointer in dm_array_cursor might be NULL if it reaches
an unreadable array block, or the array is empty. Therefore,
dm_array_cursor_end() should call dm_btree_cursor_end() unconditionally,
to prevent leaving unreleased btree blocks.
This fix can be verified using the "array_cursor/iterate/empty" test
in dm-unit:
dm-unit run /pdata/array_cursor/iterate/empty --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: Sasha Levin <sashal@kernel.org>
[ Upstream commit f2893c0804d86230ffb8f1c8703fdbb18648abc8 ]
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: Sasha Levin <sashal@kernel.org>
commit 2deb70d3e66d538404d9e71bff236e6d260da66e upstream.
Remove the redundant "i" at the beginning of the error message. This "i"
came from commit 1c1318866928 ("dm: prefer
'"%s...", __func__'"), the "i" is accidentally left.
Signed-off-by: Ssuhung Yeh <ssuhung@gmail.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 1c1318866928 ("dm: prefer '"%s...", __func__'")
Cc: stable@vger.kernel.org # v6.3+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kmalloc is unreliable when allocating more than 8 pages of memory. It may fail when there is plenty of free memory but the memory is fragmented. Zdenek Kabelac observed such failure in his tests. This commit changes kmalloc to kvmalloc - kvmalloc will fall back to vmalloc if the large allocation fails. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reported-by: Zdenek Kabelac <zkabelac@redhat.com> Reviewed-by: Mike Snitzer <snitzer@kernel.org> Cc: stable@vger.kernel.org
'struct dm_block_validator' are not modified in these drivers. Constifying this structure moves some data to a read-only section, so increase overall security. On a x86_64, with allmodconfig, as an example: Before: ====== text data bss dec hex filename 32047 920 16 32983 80d7 drivers/md/dm-cache-metadata.o After: ===== text data bss dec hex filename 32075 896 16 32987 80db drivers/md/dm-cache-metadata.o Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>