[PATCH] ath10k: add missing sanity check on diag download

[Brian Norris]

ath10k_hw_diag_fast_download() generally has good boundary checking, but
it misses verifying that the next metadata header actually fits in the
remaining buffer space. Add such a check.

Fixes: 39501ea64116 ("ath10k: download firmware via diag Copy Engine for 
QCA6174 and QCA9377.")
Signed-off-by: Brian Norris <briannor...@chromium.org>
---
 drivers/net/wireless/ath/ath10k/hw.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/hw.c 
b/drivers/net/wireless/ath/ath10k/hw.c
index 2c2870e3e84d..af8ae8117c62 100644
--- a/drivers/net/wireless/ath/ath10k/hw.c
+++ b/drivers/net/wireless/ath/ath10k/hw.c
@@ -1044,6 +1044,12 @@ int ath10k_hw_diag_fast_download(struct ath10k *ar,
        left = length - sizeof(*hdr);
 
        while (left > 0) {
+               if (left < sizeof(*metadata)) {
+                       ath10k_warn(ar, "firmware segment is truncated: %d\n",
+                                   left);
+                       ret = -EINVAL;
+                       break;
+               }
                base_addr = __le32_to_cpu(metadata->addr);
                base_len = __le32_to_cpu(metadata->length);
                buf = metadata->data;
-- 
2.19.0.444.g18242da7ef-goog