[20/85] Fix for buffer overflow in ldm_frag_add not sufficient

From: Greg KH
Date: Thu Jun 16 2011 - 03:22:06 EST

2.6.33-longterm review patch. If anyone has any objections, please let us know.


From: Timo Warns <Warns@xxxxxxxxxxxx>

commit cae13fe4cc3f24820ffb990c09110626837e85d4 upstream.

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@xxxxxxxxxxxxxxx>
Signed-off-by: Timo Warns <warns@xxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

fs/partitions/ldm.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/fs/partitions/ldm.c
+++ b/fs/partitions/ldm.c
@@ -1335,6 +1335,11 @@ static bool ldm_frag_add (const u8 *data

list_add_tail (&f->list, frags);
+ 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 */

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