[hardy, lucid/fsl-imx51, maverick/ti-omap4, natty/ti-omap4 CVE 1/1] Fix for buffer overflow in ldm_frag_add not sufficient

[Andy Whitcroft]

From: Timo Warns <Warns at pre-sense.de>

As Ben Hutchings discovered [1], the patch for CVE-2011-1017 (buffer
overflow in ldm_frag_add) is not sufficient.  The original patch in
commit c340b1d64000 ("fs/partitions/ldm.c: fix oops caused by corrupted
partition table") does not consider that, for subsequent fragments,
previously allocated memory is used.

[1] http://lkml.org/lkml/2011/5/6/407

Reported-by: Ben Hutchings <ben at decadent.org.uk>
Signed-off-by: Timo Warns <warns at pre-sense.de>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>

(cherry picked from commit cae13fe4cc3f24820ffb990c09110626837e85d4)
CVE-2011-2182
BugLink: http://bugs.launchpad.net/bugs/922371
Signed-off-by: Andy Whitcroft <apw at canonical.com>
---
 fs/partitions/ldm.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/fs/partitions/ldm.c b/fs/partitions/ldm.c
index f7b6e88..e7a38f3 100644
--- a/fs/partitions/ldm.c
+++ b/fs/partitions/ldm.c
@@ -1334,6 +1334,11 @@ static bool ldm_frag_add (const u8 *data, int size, struct list_head *frags)
 
 	list_add_tail (&f->list, frags);
 found:
+	if (rec >= f->num) {
+		ldm_error("REC value (%d) exceeds NUM value (%d)", rec, f->num);
+		return false;
+	}
+
 	if (f->map & (1 << rec)) {
 		ldm_error ("Duplicate VBLK, part %d.", rec);
 		f->map &= 0x7F;			/* Mark the group as broken */
-- 
1.7.8.3