haraldwolff/qemu-patch-raspberry4
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lm4549: Fix buffer overflow

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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>
This commit is contained in:
Stefan Weil 2012-09-01 12:43:41 +02:00 committed by Stefan Hajnoczi
parent 5d40097fc0
commit 8139626643
1 changed files with 1 additions and 1 deletions
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2
hw/lm4549.c
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@ -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;
}