Patch "cxgb4: Fix stack out-of-bounds read due to wrong size to t4_record_mbox()" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

cxgb4: Fix stack out-of-bounds read due to wrong size to t4_record_mbox()

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
cxgb4-fix-stack-out-of-bounds-read-due-to-wrong-size-to-t4_record_mbox.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stefano Brivio <[email protected]>
Date: Fri, 25 Aug 2017 22:48:48 +0200
Subject: cxgb4: Fix stack out-of-bounds read due to wrong size to t4_record_mbox()

From: Stefano Brivio <[email protected]>

[ Upstream commit 0f3086868e8889a823a6e0f3d299102aa895d947 ]

Passing commands for logging to t4_record_mbox() with size MBOX_LEN, when the actual command size is actually smaller, causes out-of-bounds stack accesses in t4_record_mbox() while copying command words here:

	for (i = 0; i < size / 8; i++)
		entry->cmd[i] = be64_to_cpu(cmd[i]);

Up to 48 bytes from the stack are then leaked to debugfs.

This happens whenever we send (and log) commands described by structs fw_sched_cmd (32 bytes leaked), fw_vi_rxmode_cmd (48), fw_hello_cmd (48), fw_bye_cmd (48), fw_initialize_cmd (48), fw_reset_cmd (48), fw_pfvf_cmd (32), fw_eq_eth_cmd (16), fw_eq_ctrl_cmd (32), fw_eq_ofld_cmd (32), fw_acl_mac_cmd(16), fw_rss_glb_config_cmd(32), fw_rss_vi_config_cmd(32), fw_devlog_cmd(32), fw_vi_enable_cmd(48), fw_port_cmd(32), fw_sched_cmd(32), fw_devlog_cmd(32).

The cxgb4vf driver got this right instead.

When we call t4_record_mbox() to log a command reply, a MBOX_LEN size can be used though, as get_mbox_rpl() will fill cmd_rpl up completely.

---
 drivers/net/ethernet/chelsio/cxgb4/t4_hw.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

@@ -369,12 +369,12 @@ int t4_wr_mbox_meat_timeout(struct adapt
 		list_del(&entry.list);
 		spin_unlock(&adap->mbox_lock);
 		ret = (v == MBOX_OWNER_FW) ? -EBUSY : -ETIMEDOUT;
-		t4_record_mbox(adap, cmd, MBOX_LEN, access, ret);
+		t4_record_mbox(adap, cmd, size, access, ret);
 		return ret;
 	}
 
 	/* Copy in the new mailbox command and send it on its way ... */
-	t4_record_mbox(adap, cmd, MBOX_LEN, access, 0);
+	t4_record_mbox(adap, cmd, size, access, 0);
 	for (i = 0; i < size; i += 8)
 		t4_write_reg64(adap, data_reg + i, be64_to_cpu(*p++));
 

@@ -426,7 +426,7 @@ int t4_wr_mbox_meat_timeout(struct adapt
 	}
 
 	ret = (pcie_fw & PCIE_FW_ERR_F) ? -ENXIO : -ETIMEDOUT;
-	t4_record_mbox(adap, cmd, MBOX_LEN, access, ret);
+	t4_record_mbox(adap, cmd, size, access, ret);
 	dev_err(adap->pdev_dev, "command %#x in mailbox %d timed out\n",
 		*(const u8 *)cmd, mbox);
 	t4_report_fw_error(adap);

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/ipv6-accept-64k-1-packet-length-in-ip6_find_1stfragopt.patch queue-4.12/sctp-avoid-out-of-bounds-reads-from-address-storage.patch queue-4.12/cxgb4-fix-stack-out-of-bounds-read-due-to-wrong-size-to-t4_record_mbox.patch