linux-kernel - [PATCH 4.4 24/91] staging: rtl: fix possible NULL pointer dereference

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20170310083901.975626115@linuxfoundation.org>
Date:   Fri, 10 Mar 2017 10:08:23 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Arnd Bergmann <arnd@...db.de>
Subject: [PATCH 4.4 24/91] staging: rtl: fix possible NULL pointer dereference

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@...db.de>

commit 6e017006022abfea5d2466cad936065f45763ad1 upstream.

gcc-7 detects that wlanhdr_to_ethhdr() in two drivers calls memcpy() with
a destination argument that an earlier function call may have set to NULL:

staging/rtl8188eu/core/rtw_recv.c: In function 'wlanhdr_to_ethhdr':
staging/rtl8188eu/core/rtw_recv.c:1318:2: warning: argument 1 null where non-null expected [-Wnonnull]
staging/rtl8712/rtl871x_recv.c: In function 'r8712_wlanhdr_to_ethhdr':
staging/rtl8712/rtl871x_recv.c:649:2: warning: argument 1 null where non-null expected [-Wnonnull]

I'm fixing this by adding a NULL pointer check and returning failure
from the function, which is hopefully already handled properly.

This seems to date back to when the drivers were originally added,
so backporting the fix to stable seems appropriate. There are other
related realtek drivers in the kernel, but none of them contain a
function with a similar name or produce this warning.

Fixes: 1cc18a22b96b ("staging: r8188eu: Add files for new driver - part 5")
Fixes: 2865d42c78a9 ("staging: r8712u: Add the new driver to the mainline kernel")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/staging/rtl8188eu/core/rtw_recv.c |    3 +++
 drivers/staging/rtl8712/rtl871x_recv.c    |    7 ++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/staging/rtl8188eu/core/rtw_recv.c
+++ b/drivers/staging/rtl8188eu/core/rtw_recv.c
@@ -1405,6 +1405,9 @@ static int wlanhdr_to_ethhdr(struct recv
 		ptr = recvframe_pull(precvframe, (rmv_len-sizeof(struct ethhdr) + (bsnaphdr ? 2 : 0)));
 	}
 
+	if (!ptr)
+		return _FAIL;
+
 	memcpy(ptr, pattrib->dst, ETH_ALEN);
 	memcpy(ptr+ETH_ALEN, pattrib->src, ETH_ALEN);
 
--- a/drivers/staging/rtl8712/rtl871x_recv.c
+++ b/drivers/staging/rtl8712/rtl871x_recv.c
@@ -641,11 +641,16 @@ sint r8712_wlanhdr_to_ethhdr(union recv_
 		/* append rx status for mp test packets */
 		ptr = recvframe_pull(precvframe, (rmv_len -
 		      sizeof(struct ethhdr) + 2) - 24);
+		if (!ptr)
+			return _FAIL;
 		memcpy(ptr, get_rxmem(precvframe), 24);
 		ptr += 24;
-	} else
+	} else {
 		ptr = recvframe_pull(precvframe, (rmv_len -
 		      sizeof(struct ethhdr) + (bsnaphdr ? 2 : 0)));
+		if (!ptr)
+			return _FAIL;
+	}
 
 	memcpy(ptr, pattrib->dst, ETH_ALEN);
 	memcpy(ptr + ETH_ALEN, pattrib->src, ETH_ALEN);