wifi: mwifiex: bound SDIO fw dump count by memory table size

From: Tianchu Chen <[email protected]>

mwifiex_sdio_fw_dump() reads the number of memory regions (dump_num) from a device register and uses it to index the static 15-entry mem_type_mapping_tbl[] without any bounds check. A bogus device can report a dump_num larger than the table; each out-of-table loop iteration then reads entry->mem_name and entry->done_flag and stores a vmalloc pointer and a device-controlled size past the end of the table, into adjacent .data (up to ~5.6KiB when dump_num is 255).

The dump path runs after command timeouts or firmware crashes, so a bogus device can first force an error to trigger the dump and then report a bogus dump_num.

Limit dump_num to the table size instead of aborting the dump. This is not expected to change the behavior on normal devices.

Discovered by Atuin - Automated Vulnerability Discovery Engine.

---
v2: clamp dump_num to the table size and continue when bogus dump_num detected.

 drivers/net/wireless/marvell/mwifiex/sdio.c | 3 +++
 1 file changed, 3 insertions(+)

index f039d6f19183a..c15d6e1dd8f63 100644
@@ -2795,6 +2795,9 @@ static void mwifiex_sdio_fw_dump(struct mwifiex_adapter *adapter)
 		mwifiex_dbg(adapter, ERROR, "SDIO read memory length err\n");
 		goto done;
 	}
+	/* Limit the dump count to the memory table size */
+	if (dump_num > ARRAY_SIZE(mem_type_mapping_tbl))
+		dump_num = ARRAY_SIZE(mem_type_mapping_tbl);
 
 	/* Read the length of every memory which will dump */
 	for (idx = 0; idx < dump_num; idx++) {

2.51.0

Oops, didn't notice v2 when reviewing v1. This is a valid choice too; probably a better one.