[PATCH 4.4 40/40] ALSA: isa/wavefront: prevent some out of bound writes

From: Greg Kroah-Hartman
Date: Thu Dec 20 2018 - 04:43:19 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

[ Upstream commit 84d7a4470dbac0dd9389050100b54a1625d04264 ]

"header->number" can be up to USHRT_MAX and it comes from the ioctl so
it needs to be capped.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
sound/isa/wavefront/wavefront_synth.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
index 69f76ff5693d..718d5e3b7806 100644
--- a/sound/isa/wavefront/wavefront_synth.c
+++ b/sound/isa/wavefront/wavefront_synth.c
@@ -785,6 +785,9 @@ wavefront_send_patch (snd_wavefront_t *dev, wavefront_patch_info *header)
DPRINT (WF_DEBUG_LOAD_PATCH, "downloading patch %d\n",
header->number);

+ if (header->number >= ARRAY_SIZE(dev->patch_status))
+ return -EINVAL;
+
dev->patch_status[header->number] |= WF_SLOT_FILLED;

bptr = buf;
@@ -809,6 +812,9 @@ wavefront_send_program (snd_wavefront_t *dev, wavefront_patch_info *header)
DPRINT (WF_DEBUG_LOAD_PATCH, "downloading program %d\n",
header->number);

+ if (header->number >= ARRAY_SIZE(dev->prog_status))
+ return -EINVAL;
+
dev->prog_status[header->number] = WF_SLOT_USED;

/* XXX need to zero existing SLOT_USED bit for program_status[i]
@@ -898,6 +904,9 @@ wavefront_send_sample (snd_wavefront_t *dev,
header->number = x;
}

+ if (header->number >= WF_MAX_SAMPLE)
+ return -EINVAL;
+
if (header->size) {

/* XXX it's a debatable point whether or not RDONLY semantics
--
2.19.1