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| author | Alden Tondettar | 2017-01-24 07:27:59 +0100 |
|---|---|---|
| committer | Karel Zak | 2017-01-25 11:39:10 +0100 |
| commit | 999a2ffec92fdecbc1bc85f521057215bcc5ba84 (patch) | |
| tree | 4fb6dd2e5992bb19496b40c06246a9d14954afa7 /libblkid/src/superblocks/ntfs.c | |
| parent | libblkid: Fix out of bounds byte swaps in ZFS handling (diff) | |
| download | kernel-qcow2-util-linux-999a2ffec92fdecbc1bc85f521057215bcc5ba84.tar.gz kernel-qcow2-util-linux-999a2ffec92fdecbc1bc85f521057215bcc5ba84.tar.xz kernel-qcow2-util-linux-999a2ffec92fdecbc1bc85f521057215bcc5ba84.zip | |
libblkid: Fix out of bounds reads on bad NTFS Master File Table
The NTFS prober does not validate certain fields in struct file_attribute,
and could attempt to read the disk label from outside the space allocated
for the Master File Table. Perform the appropriate checks.
Note that one variable (attr_off) is now 64-bit, so a check for integer
overflow has been removed as unneeded/confusing.
Signed-off-by: Alden Tondettar <alden.tondettar@gmail.com>
Diffstat (limited to 'libblkid/src/superblocks/ntfs.c')
| -rw-r--r-- | libblkid/src/superblocks/ntfs.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/libblkid/src/superblocks/ntfs.c b/libblkid/src/superblocks/ntfs.c index 751581164..3a9d5cb01 100644 --- a/libblkid/src/superblocks/ntfs.c +++ b/libblkid/src/superblocks/ntfs.c @@ -84,9 +84,9 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag) struct ntfs_super_block *ns; struct master_file_table_record *mft; - uint32_t sectors_per_cluster, mft_record_size, attr_off; + uint32_t sectors_per_cluster, mft_record_size; uint16_t sector_size; - uint64_t nr_clusters, off; + uint64_t nr_clusters, off, attr_off; unsigned char *buf_mft; ns = blkid_probe_get_sb(pr, mag, struct ntfs_super_block); @@ -175,7 +175,7 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag) mft = (struct master_file_table_record *) buf_mft; attr_off = le16_to_cpu(mft->attrs_offset); - while (attr_off < mft_record_size && + while (attr_off + sizeof(struct file_attribute) <= mft_record_size && attr_off <= le32_to_cpu(mft->bytes_allocated)) { uint32_t attr_len; @@ -193,12 +193,12 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag) unsigned int val_len = le32_to_cpu(attr->value_len); unsigned char *val = ((uint8_t *) attr) + val_off; - blkid_probe_set_utf8label(pr, val, val_len, BLKID_ENC_UTF16LE); + if (attr_off + val_off + val_len <= mft_record_size) + blkid_probe_set_utf8label(pr, val, val_len, + BLKID_ENC_UTF16LE); break; } - if (UINT_MAX - attr_len < attr_off) - break; attr_off += attr_len; } |