Commit 8412886a authored by Kees Cook's avatar Kees Cook Committed by Luis Henriques

mac: validate mac_partition is within sector

commit 02e2a5bf upstream.

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: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 70664601
...@@ -32,7 +32,7 @@ int mac_partition(struct parsed_partitions *state) ...@@ -32,7 +32,7 @@ int mac_partition(struct parsed_partitions *state)
Sector sect; Sector sect;
unsigned char *data; unsigned char *data;
int slot, blocks_in_map; int slot, blocks_in_map;
unsigned secsize; unsigned secsize, datasize, partoffset;
#ifdef CONFIG_PPC_PMAC #ifdef CONFIG_PPC_PMAC
int found_root = 0; int found_root = 0;
int found_root_goodness = 0; int found_root_goodness = 0;
...@@ -50,10 +50,14 @@ int mac_partition(struct parsed_partitions *state) ...@@ -50,10 +50,14 @@ int mac_partition(struct parsed_partitions *state)
} }
secsize = be16_to_cpu(md->block_size); secsize = be16_to_cpu(md->block_size);
put_dev_sector(sect); put_dev_sector(sect);
data = read_part_sector(state, secsize/512, &sect); datasize = round_down(secsize, 512);
data = read_part_sector(state, datasize / 512, &sect);
if (!data) if (!data)
return -1; 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) { if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) {
put_dev_sector(sect); put_dev_sector(sect);
return 0; /* not a MacOS disk */ return 0; /* not a MacOS disk */
......
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