The patch titled
Subject: mm/cma_debug.c: fix stack corruption due to sprintf usage
has been added to the -mm tree. Its filename is
mm-cma-fix-stack-corruption-due-to-sprintf-usage.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-cma-fix-stack-corruption-due-to-sprintf-usage.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-cma-fix-stack-corruption-due-to-sprintf-usage.patch
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------------------------------------------------------
From: Prakash Gupta <guptap@xxxxxxxxxxxxxx>
Subject: mm/cma_debug.c: fix stack corruption due to sprintf usage
name[] in cma_debugfs_add_one() can only accommodate 16 chars including
NULL to store sprintf output. It's common for cma device name to be
larger than 15 chars. This can cause stack corrpution. If the gcc stack
protector is turned on, this can cause a panic due to stack corruption.
Below is one example trace:
Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in:
ffffff8e69a75730
Call trace:
[<ffffff8e68289504>] dump_backtrace+0x0/0x2c4
[<ffffff8e682897e8>] show_stack+0x20/0x28
[<ffffff8e685ea808>] dump_stack+0xb8/0xf4
[<ffffff8e683c454c>] panic+0x154/0x2b0
[<ffffff8e682a724c>] print_tainted+0x0/0xc0
[<ffffff8e69a75730>] cma_debugfs_init+0x274/0x290
[<ffffff8e682839ec>] do_one_initcall+0x5c/0x168
[<ffffff8e69a50e24>] kernel_init_freeable+0x1c8/0x280
Fix the short sprintf buffer in cma_debugfs_add_one() by using scnprintf()
instead of sprintf().
Link: http://lkml.kernel.org/r/1502446217-21840-1-git-send-email-guptap@xxxxxxxxxxxxxx
Fixes: f318dd083c81 ("cma: Store a name in the cma structure")
Signed-off-by: Prakash Gupta <guptap@xxxxxxxxxxxxxx>
Acked-by: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/cma_debug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/cma_debug.c~mm-cma-fix-stack-corruption-due-to-sprintf-usage mm/cma_debug.c
--- a/mm/cma_debug.c~mm-cma-fix-stack-corruption-due-to-sprintf-usage
+++ a/mm/cma_debug.c
@@ -167,7 +167,7 @@ static void cma_debugfs_add_one(struct c
char name[16];
int u32s;
- sprintf(name, "cma-%s", cma->name);
+ scnprintf(name, sizeof(name), "cma-%s", cma->name);
tmp = debugfs_create_dir(name, cma_debugfs_root);
_
Patches currently in -mm which might be from guptap@xxxxxxxxxxxxxx are
mm-cma-fix-stack-corruption-due-to-sprintf-usage.patch
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