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From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org
Cc: Eric Sesterhenn <snakebyte@gmx.de>, Roman Zippel <zippel@linux-m68k.org>,
       550010@bugs.debian.org
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Date: Sun, 11 Oct 2009 03:11:27 +0100
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Subject: [PATCH] hfsplus: Refuse to mount volumes larger than 2TB
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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.