diff options
| author | Kees Cook <keescook@chromium.org> | 2015-11-19 17:18:54 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-11-20 08:49:28 -0700 |
| commit | 02e2a5bfebe99edcf9d694575a75032d53fe1b73 (patch) | |
| tree | 815d3e15f91df416bdabd567d11f3983fa48f383 /block | |
| parent | 8aeea03195ee6e33fcb00039c414eabfc37a4eb8 (diff) | |
| download | lwn-02e2a5bfebe99edcf9d694575a75032d53fe1b73.tar.gz lwn-02e2a5bfebe99edcf9d694575a75032d53fe1b73.zip | |
mac: validate mac_partition is within sector
If md->signature == MAC_DRIVER_MAGIC and md->block_size == 1023, a single
512 byte sector would be read (secsize / 512). However the partition
structure would be located past the end of the buffer (secsize % 512).
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/partitions/mac.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/block/partitions/mac.c b/block/partitions/mac.c index c2c48ec64b27..621317ac4d59 100644 --- a/block/partitions/mac.c +++ b/block/partitions/mac.c @@ -32,7 +32,7 @@ int mac_partition(struct parsed_partitions *state) Sector sect; unsigned char *data; int slot, blocks_in_map; - unsigned secsize; + unsigned secsize, datasize, partoffset; #ifdef CONFIG_PPC_PMAC int found_root = 0; int found_root_goodness = 0; @@ -50,10 +50,14 @@ int mac_partition(struct parsed_partitions *state) } secsize = be16_to_cpu(md->block_size); put_dev_sector(sect); - data = read_part_sector(state, secsize/512, §); + datasize = round_down(secsize, 512); + data = read_part_sector(state, datasize / 512, §); if (!data) return -1; - part = (struct mac_partition *) (data + secsize%512); + partoffset = secsize % 512; + if (partoffset + sizeof(*part) > datasize) + return -1; + part = (struct mac_partition *) (data + partoffset); if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) { put_dev_sector(sect); return 0; /* not a MacOS disk */ |