[PATCH 4/4] venus: hfi_parser: Add check to keep the number of codecs within range

[Vikash Garodia]

Supported codec bitmask is populated from the payload from venus firmware.
There is a possible case when all the bits in the codec bitmask is set. In
such case, core cap for decoder is filled  and MAX_CODEC_NUM is utilized.
Now while filling the caps for encoder, it can lead to access the caps
array beyong 32 index. Hence leading to OOB write.
The fix counts the supported encoder and decoder. If the count is more than
max, then it skips accessing the caps.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1a73374a04e5 ("media: venus: hfi_parser: add common capability parser")
Signed-off-by: Vikash Garodia <quic_vgarodia@xxxxxxxxxxx>
---
 drivers/media/platform/qcom/venus/hfi_parser.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/media/platform/qcom/venus/hfi_parser.c b/drivers/media/platform/qcom/venus/hfi_parser.c
index ec73cac..651e215 100644
--- a/drivers/media/platform/qcom/venus/hfi_parser.c
+++ b/drivers/media/platform/qcom/venus/hfi_parser.c
@@ -14,11 +14,26 @@
 typedef void (*func)(struct hfi_plat_caps *cap, const void *data,
 		     unsigned int size);
 
+static int count_setbits(u32 input)
+{
+	u32 count = 0;
+
+	while (input > 0) {
+		if ((input & 1) == 1)
+			count++;
+		input >>= 1;
+	}
+	return count;
+}
+
 static void init_codecs(struct venus_core *core)
 {
 	struct hfi_plat_caps *caps = core->caps, *cap;
 	unsigned long bit;
 
+	if ((count_setbits(core->dec_codecs) + count_setbits(core->enc_codecs)) > MAX_CODEC_NUM)
+		return;
+
 	for_each_set_bit(bit, &core->dec_codecs, MAX_CODEC_NUM) {
 		cap = &caps[core->codecs_count++];
 		cap->codec = BIT(bit);
-- 
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