From: Tobias Stoeckmann Date: Wed, 15 Mar 2017 21:12:00 +0000 (+0100) Subject: libblkid: prevent OOB access while probing HFS+ X-Git-Tag: v2.30-rc1~166 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=62ab1ebb12e812b15382318861a594c946b6238e;p=thirdparty%2Futil-linux.git libblkid: prevent OOB access while probing HFS+ It is possible to perform out of boundary read accesses due to insufficient boundary checks in probe_hfsplus. The first issue occurs if the leaf count in a B-node is too small. The second happens while parsing a unicode description which is longer than 255 UTF-8 characters. The length is stored in a 16 bit integer, but the array in the struct is limited to 255 * 2, which is in sync with Apple's Open Source HFS+ implementation (HFSUniStr255). Signed-off-by: Tobias Stoeckmann --- diff --git a/libblkid/src/superblocks/hfs.c b/libblkid/src/superblocks/hfs.c index ee502cf61f..ef746d4e29 100644 --- a/libblkid/src/superblocks/hfs.c +++ b/libblkid/src/superblocks/hfs.c @@ -244,7 +244,8 @@ static int probe_hfsplus(blkid_probe pr, const struct blkid_idmag *mag) leaf_node_head = be32_to_cpu(bnode->leaf_head); leaf_node_size = be16_to_cpu(bnode->node_size); leaf_node_count = be32_to_cpu(bnode->leaf_count); - if (leaf_node_count == 0) + if (leaf_node_size < sizeof(struct hfsplus_bnode_descriptor) + + sizeof(struct hfsplus_catalog_key) || leaf_node_count == 0) return 0; leaf_block = (leaf_node_head * leaf_node_size) / blocksize; @@ -284,7 +285,8 @@ static int probe_hfsplus(blkid_probe pr, const struct blkid_idmag *mag) key = (struct hfsplus_catalog_key *) &buf[sizeof(struct hfsplus_bnode_descriptor)]; - if (be32_to_cpu(key->parent_id) != HFSPLUS_POR_CNID) + if (be32_to_cpu(key->parent_id) != HFSPLUS_POR_CNID || + be16_to_cpu(key->unicode_len > 255)) return 0; blkid_probe_set_utf8label(pr, key->unicode,