diff options
| author | Jann Horn <jannh@google.com> | 2025-02-14 02:39:50 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-02-14 08:38:28 -0700 |
| commit | 80e648042e512d5a767da251d44132553fe04ae0 (patch) | |
| tree | 4516f9009fa27b77f790cb09c7a44dd6a955ab9e /block | |
| parent | 1f47ed294a2bd577d5ae43e6e28e1c9a3be4a833 (diff) | |
partitions: mac: fix handling of bogus partition table
Fix several issues in partition probing:
- The bailout for a bad partoffset must use put_dev_sector(), since the
preceding read_part_sector() succeeded.
- If the partition table claims a silly sector size like 0xfff bytes
(which results in partition table entries straddling sector boundaries),
bail out instead of accessing out-of-bounds memory.
- We must not assume that the partition table contains proper NUL
termination - use strnlen() and strncmp() instead of strlen() and
strcmp().
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20250214-partition-mac-v1-1-c1c626dffbd5@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/partitions/mac.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/block/partitions/mac.c b/block/partitions/mac.c index c80183156d68..b02530d98629 100644 --- a/block/partitions/mac.c +++ b/block/partitions/mac.c @@ -53,13 +53,25 @@ int mac_partition(struct parsed_partitions *state) } secsize = be16_to_cpu(md->block_size); put_dev_sector(sect); + + /* + * If the "block size" is not a power of 2, things get weird - we might + * end up with a partition straddling a sector boundary, so we wouldn't + * be able to read a partition entry with read_part_sector(). + * Real block sizes are probably (?) powers of two, so just require + * that. + */ + if (!is_power_of_2(secsize)) + return -1; datasize = round_down(secsize, 512); data = read_part_sector(state, datasize / 512, §); if (!data) return -1; partoffset = secsize % 512; - if (partoffset + sizeof(*part) > datasize) + if (partoffset + sizeof(*part) > datasize) { + put_dev_sector(sect); return -1; + } part = (struct mac_partition *) (data + partoffset); if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) { put_dev_sector(sect); @@ -112,8 +124,8 @@ int mac_partition(struct parsed_partitions *state) int i, l; goodness++; - l = strlen(part->name); - if (strcmp(part->name, "/") == 0) + l = strnlen(part->name, sizeof(part->name)); + if (strncmp(part->name, "/", sizeof(part->name)) == 0) goodness++; for (i = 0; i <= l - 4; ++i) { if (strncasecmp(part->name + i, "root", |