[33/99] hfsplus: refuse to mount volumes larger than 2TB

From: Greg KH
Date: Fri Nov 06 2009 - 17:39:00 EST

2.6.31-stable review patch. If anyone has any objections, please let us know.

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

commit 5c36fe3d87b3f0c85894a49193c66096a3d6b26f upstream.

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).

[akpm@xxxxxxxxxxxxxxxxxxxx: fix 32 and 64-bit issues]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Eric Sesterhenn <snakebyte@xxxxxx>
Cc: Roman Zippel <zippel@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

fs/hfsplus/wrapper.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/fs/hfsplus/wrapper.c
+++ b/fs/hfsplus/wrapper.c
@@ -99,6 +99,10 @@ int hfsplus_read_wrapper(struct super_bl

if (hfsplus_get_last_session(sb, &part_start, &part_size))
return -EINVAL;
+ if ((u64)part_start + part_size > 0x100000000ULL) {
+ 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)

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