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 <tobias@xxxxxxxxxxxxxx> --- You can trigger the issue with these two small proof of concepts, which contain byte sequences which imitate a HFS+ (but are broken beyond repair, as I was just fiddling around with bits until they did what I wanted to happen ;) ). echo H4sICJKhyVgCA2lzby1wb2MtMQDt1LkNgDAURMFviSt1B9SCHNCAJTo\ hpXPjEkiBmfhFG+xWai1d684uIlJrOccVMU7zEimAj9qPp+Xw45VWLwgAAAA\ AAMAr3DUKOtIAIAAA | base64 -d - | gunzip > f1 echo H4sICKelyVgCA2lzby1wb2MtMgDt2rsJgFAMBdA88Ne6gbOIhQsIbuL\ 48QkOYKue09wUKcOtMi/btlRZHVVElMxxrDm0XT80AXzVuj/d/HMTTMWlAAA\ AAAAA8CYZmfdYrl+AGfi8Exgn/EMAJAAA | base64 -d - | gunzip > f2 You can trigger the issue with the tool blkid this way: # losetup -f $file # blkid -p -n hfsplus /dev/loop0 --- libblkid/src/superblocks/hfs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/libblkid/src/superblocks/hfs.c b/libblkid/src/superblocks/hfs.c index ee502cf61..ef746d4e2 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, -- 2.12.0 -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
