firmware: cs_dsp: Validate payload length before processing block

[ Upstream commit 6598afa9320b6ab13041616950ca5f8f938c0cf1 ]

Move the payload length check in cs_dsp_load() and cs_dsp_coeff_load()
to be done before the block is processed.

The check that the length of a block payload does not exceed the number
of remaining bytes in the firwmware file buffer was being done near the
end of the loop iteration. However, some code before that check used the
length field without validating it.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: f6bc909 ("firmware: cs_dsp: add driver to support firmware loading on Cirrus Logic DSPs")
Link: https://patch.msgid.link/20240627141432.93056-4-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 3a9cd924aec1288d675df721f244da4dd7e16cff)

drivers/firmware/cirrus/cs_dsp.c

@@ -1398,6 +1398,12 @@ static int cs_dsp_load(struct cs_dsp *dsp, const struct firmware *firmware,
 		}
 
 		region = (void *)&(firmware->data[pos]);
+
+		if (le32_to_cpu(region->len) > firmware->size - pos - sizeof(*region)) {
+			ret = -EOVERFLOW;
+			goto out_fw;
+		}
+
 		region_name = "Unknown";
 		reg = 0;
 		text = NULL;
@@ -1454,16 +1460,6 @@ static int cs_dsp_load(struct cs_dsp *dsp, const struct firmware *firmware,
 			   regions, le32_to_cpu(region->len), offset,
 			   region_name);
 
-		if (le32_to_cpu(region->len) >
-		    firmware->size - pos - sizeof(*region)) {
-			cs_dsp_err(dsp,
-				   "%s.%d: %s region len %d bytes exceeds file length %zu\n",
-				   file, regions, region_name,
-				   le32_to_cpu(region->len), firmware->size);
-			ret = -EINVAL;
-			goto out_fw;
-		}
-
 		if (text) {
 			memcpy(text, region->data, le32_to_cpu(region->len));
 			cs_dsp_info(dsp, "%s: %s\n", file, text);
@@ -2093,6 +2089,11 @@ static int cs_dsp_load_coeff(struct cs_dsp *dsp, const struct firmware *firmware
 
 		blk = (void *)(&firmware->data[pos]);
 
+		if (le32_to_cpu(blk->len) > firmware->size - pos - sizeof(*blk)) {
+			ret = -EOVERFLOW;
+			goto out_fw;
+		}
+
 		type = le16_to_cpu(blk->type);
 		offset = le16_to_cpu(blk->offset);
 		version = le32_to_cpu(blk->ver) >> 8;
@@ -2189,17 +2190,6 @@ static int cs_dsp_load_coeff(struct cs_dsp *dsp, const struct firmware *firmware
 		}
 
 		if (reg) {
-			if (le32_to_cpu(blk->len) >
-			    firmware->size - pos - sizeof(*blk)) {
-				cs_dsp_err(dsp,
-					   "%s.%d: %s region len %d bytes exceeds file length %zu\n",
-					   file, blocks, region_name,
-					   le32_to_cpu(blk->len),
-					   firmware->size);
-				ret = -EINVAL;
-				goto out_fw;
-			}
-
 			buf = cs_dsp_buf_alloc(blk->data,
 					       le32_to_cpu(blk->len),
 					       &buf_list);
@@ -2239,6 +2229,10 @@ static int cs_dsp_load_coeff(struct cs_dsp *dsp, const struct firmware *firmware
 	regmap_async_complete(regmap);
 	cs_dsp_buf_free(&buf_list);
 	kfree(text);
+
+	if (ret == -EOVERFLOW)
+		cs_dsp_err(dsp, "%s: file content overflows file data\n", file);
+
 	return ret;
 }