| From | Paul Gortmaker <> | Subject | [34-longterm 127/196] Fix corrupted OSF partition table parsing | Date | Mon, 12 Mar 2012 20:20:40 -0400 |
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From: Timo Warns <Warns@pre-sense.de>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
commit 1eafbfeb7bdf59cfe173304c76188f3fd5f1fd05 upstream.
The kernel automatically evaluates partition tables of storage devices. The code for evaluating OSF partitions contains a bug that leaks data from kernel heap memory to userspace for certain corrupted OSF partitions.
In more detail:
for (i = 0 ; i < le16_to_cpu(label->d_npartitions); i++, partition++) {
iterates from 0 to d_npartitions - 1, where d_npartitions is read from the partition table without validation and partition is a pointer to an array of at most 8 d_partitions.
Add the proper and obvious validation.
Signed-off-by: Timo Warns <warns@pre-sense.de> [ Changed the patch trivially to not repeat the whole le16_to_cpu() thing, and to use an explicit constant for the magic value '8' ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/partitions/osf.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/partitions/osf.c b/fs/partitions/osf.c index c05c17bc..6e0825e 100644 --- a/fs/partitions/osf.c +++ b/fs/partitions/osf.c @@ -10,10 +10,13 @@ #include "check.h" #include "osf.h" +#define MAX_OSF_PARTITIONS 8 + int osf_partition(struct parsed_partitions *state, struct block_device *bdev) { int i; int slot = 1; + unsigned int npartitions; Sector sect; unsigned char *data; struct disklabel { @@ -45,7 +48,7 @@ int osf_partition(struct parsed_partitions *state, struct block_device *bdev) u8 p_fstype; u8 p_frag; __le16 p_cpg; - } d_partitions[8]; + } d_partitions[MAX_OSF_PARTITIONS]; } * label; struct d_partition * partition; @@ -63,7 +66,12 @@ int osf_partition(struct parsed_partitions *state, struct block_device *bdev) put_dev_sector(sect); return 0; } - for (i = 0 ; i < le16_to_cpu(label->d_npartitions); i++, partition++) { + npartitions = le16_to_cpu(label->d_npartitions); + if (npartitions > MAX_OSF_PARTITIONS) { + put_dev_sector(sect); + return 0; + } + for (i = 0 ; i < npartitions; i++, partition++) { if (slot == state->limit) break; if (le32_to_cpu(partition->p_size)) -- 1.7.9.3
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