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>

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index 593b7d1..d72ccef 100644 (file)
--- 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);