[PATCH] hfsplus: Refuse to mount volumes larger than 2TB

Ben Hutchings
2009-10-11T02:12:13Z

As found in <http://bugs.debian.org/550010>, hfsplus is using type u32
rather than sector_t for some sector number calculations.

In particular, hfsplus_get_block() does:

u32 ablock, dblock, mask;
...
map_bh(bh_result, sb, (dblock << HFSPLUS_SB(sb).fs_shift) + HFSPLUS_SB(sb).blockoffset + (iblock & mask));

I am not confident that I can find and fix all cases where a sector
number may be truncated. For now, avoid data loss by refusing to mount
HFS+ volumes with more than 2^32 sectors (2TB).

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@kernel.org
---
--- a/fs/hfsplus/wrapper.c
+++ b/fs/hfsplus/wrapper.c
@@ -99,6 +99,10 @@

if (hfsplus_get_last_session(sb, &part_start, &part_size))
return -EINVAL;
+ if (part_start + part_size > 0x100000000) {
+ pr_err("hfs: volumes larger than 2TB are not supported yet\n");
+ return -EINVAL;
+ }
while (1) {
bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
if (!bh)

--
Ben Hutchings
Quantity is no substitute for quality, but it's the only one we've got.