ASoC: wm_adsp: Don't overrun firmware file buffer when reading region data

Protect against corrupt firmware files by ensuring that the length we
get for the data in a region actually lies within the available firmware
file data buffer.

Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 24 insertions, 1 deletions

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index 593b7d1aed46..d72ccef9e238 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -1551,7 +1551,7 @@ static int wm_adsp_load(struct wm_adsp *dsp)
         const struct wmfw_region *region;
         const struct wm_adsp_region *mem;
         const char *region_name;
-        char *file, *text;
+        char *file, *text = NULL;
         struct wm_adsp_buf *buf;
         unsigned int reg;
         int regions = 0;
@@ -1700,10 +1700,21 @@ static int wm_adsp_load(struct wm_adsp *dsp)
                          regions, le32_to_cpu(region->len), offset,
                          region_name);
 
+                if ((pos + le32_to_cpu(region->len) + sizeof(*region)) >
+                    firmware->size) {
+                        adsp_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));
                         adsp_info(dsp, "%s: %s\n", file, text);
                         kfree(text);
+                        text = NULL;
                 }
 
                 if (reg) {
@@ -1748,6 +1759,7 @@ out_fw:
         regmap_async_complete(regmap);
         wm_adsp_buf_free(&buf_list);
         release_firmware(firmware);
+        kfree(text);
 out:
         kfree(file);
 
@@ -2233,6 +2245,17 @@ static int wm_adsp_load_coeff(struct wm_adsp *dsp)
                 }
 
                 if (reg) {
+                        if ((pos + le32_to_cpu(blk->len) + sizeof(*blk)) >
+                            firmware->size) {
+                                adsp_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 = wm_adsp_buf_alloc(blk->data,
                                                 le32_to_cpu(blk->len),
                                                 &buf_list);