wl12xx: Check buffer bound when processing nvs data

An nvs with malformed contents could cause the processing of the
calibration data to read beyond the end of the buffer. Prevent this
from happening by adding bound checking.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Cc: stable@kernel.org
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/wl12xx/boot.c

@@ -348,6 +348,9 @@ static int wl1271_boot_upload_nvs(struct wl1271 *wl)
 		nvs_ptr += 3;
 
 		for (i = 0; i < burst_len; i++) {
+			if (nvs_ptr + 3 >= (u8 *) wl->nvs + nvs_len)
+				goto out_badnvs;
+
 			val = (nvs_ptr[0] | (nvs_ptr[1] << 8)
 			       | (nvs_ptr[2] << 16) | (nvs_ptr[3] << 24));
 
@@ -359,6 +362,9 @@ static int wl1271_boot_upload_nvs(struct wl1271 *wl)
 			nvs_ptr += 4;
 			dest_addr += 4;
 		}
+
+		if (nvs_ptr >= (u8 *) wl->nvs + nvs_len)
+			goto out_badnvs;
 	}
 
 	/*
@@ -370,6 +376,10 @@ static int wl1271_boot_upload_nvs(struct wl1271 *wl)
 	 */
 	nvs_ptr = (u8 *)wl->nvs +
 			ALIGN(nvs_ptr - (u8 *)wl->nvs + 7, 4);
+
+	if (nvs_ptr >= (u8 *) wl->nvs + nvs_len)
+		goto out_badnvs;
+
 	nvs_len -= nvs_ptr - (u8 *)wl->nvs;
 
 	/* Now we must set the partition correctly */
@@ -385,6 +395,10 @@ static int wl1271_boot_upload_nvs(struct wl1271 *wl)
 
 	kfree(nvs_aligned);
 	return 0;
+
+out_badnvs:
+	wl1271_error("nvs data is malformed");
+	return -EILSEQ;
 }
 
 static void wl1271_boot_enable_interrupts(struct wl1271 *wl)