[PATCH] ide: don't call memcpy with the same source and destination

[PATCH] ide: don't call memcpy with the same source and destination

[Mikulas Patocka]

The parisc architecture recently reimplemented the memcpy function and
their reimplementation crashed when source and destination overlapped.

The crash happened in the function ide_complete_cmd where memcpy is called
with the same source and destination pointer. According to the C
specification, memcpy behavior is undefined if the source and destination
range overlaps. This patches fixes the undefined behavior.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/ide/ide-io.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-4.11-rc6/drivers/ide/ide-io.c
===================================================================
--- linux-4.11-rc6.orig/drivers/ide/ide-io.c
+++ linux-4.11-rc6/drivers/ide/ide-io.c
@@ -107,7 +107,7 @@ void ide_complete_cmd(ide_drive_t *drive
 
 		if (cmd->tf_flags & IDE_TFLAG_DYN)
 			kfree(orig_cmd);
-		else
+		else if (cmd != orig_cmd)
 			memcpy(orig_cmd, cmd, sizeof(*cmd));
 	}
 }

Re: [PATCH] ide: don't call memcpy with the same source and destination

[Bartlomiej Zolnierkiewicz]

On Friday, April 14, 2017 02:35:33 PM Mikulas Patocka wrote:
> The parisc architecture recently reimplemented the memcpy function and
> their reimplementation crashed when source and destination overlapped.
> 
> The crash happened in the function ide_complete_cmd where memcpy is called
> with the same source and destination pointer. According to the C
> specification, memcpy behavior is undefined if the source and destination
> range overlaps. This patches fixes the undefined behavior.
> 
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH] ide: don't call memcpy with the same source and destination

[David Miller]

From: Mikulas Patocka <mpatocka@redhat.com>
Date: Fri, 14 Apr 2017 14:35:33 -0400 (EDT)

> The parisc architecture recently reimplemented the memcpy function and
> their reimplementation crashed when source and destination overlapped.
> 
> The crash happened in the function ide_complete_cmd where memcpy is called
> with the same source and destination pointer. According to the C
> specification, memcpy behavior is undefined if the source and destination
> range overlaps. This patches fixes the undefined behavior.
> 
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Applied.