From 00338325c4a2c5b0010462b21a4373cbb4341c9d Mon Sep 17 00:00:00 2001

From: Stefan Weil <sw@weilnetz.de>

Date: Sat, 1 Sep 2012 12:43:41 +0200

Subject: [PATCH] lm4549: Fix buffer overflow

Report from smatch:

lm4549.c:234 lm4549_write_samples(14) error:

 buffer overflow 's->buffer' 1024 <= 1024

There must be enough space to add two entries starting with index

s->buffer_level, therefore the old check was wrong.

[Peter Maydell <peter.maydell@linaro.org> clarifies the nature of the

analyser warning:

I don't object to making the change to placate the analyser,

but I don't think this is actually a buffer overrun. We always

add and remove samples from the buffer two at a time, so it's

not possible to get here with s->buffer_level == BUFFER_SIZE-1

(which is the only case where the old and new conditions

give different answers).]

Signed-off-by: Stefan Weil <sw@weilnetz.de>

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>

(cherry picked from commit 8139626643cbe8dc07bd9acc88057effeedf8064)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

---

 hw/lm4549.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/lm4549.c b/hw/lm4549.c

index 80b3ec4..e0137d5 100644

--- a/hw/lm4549.c

+++ b/hw/lm4549.c

@@ -224,7 +224,7 @@ uint32_t lm4549_write_samples(lm4549_state *s, uint32_t left, uint32_t right)

        This model supports 16-bit playback.

     */

-    if (s->buffer_level >= LM4549_BUFFER_SIZE) {

+    if (s->buffer_level > LM4549_BUFFER_SIZE - 2) {

         DPRINTF("write_sample Buffer full\n");

         return 0;

     }

-- 

1.7.12.1