From: Arnd Bergmann Date: Wed, 11 Jan 2017 14:53:08 +0000 (+0100) Subject: staging: rtl: fix possible NULL pointer dereference X-Git-Tag: v3.2.89~85 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=17712d0edb8f870a1c5bec94a91a25f6f60614cd staging: rtl: fix possible NULL pointer dereference 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 Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: drop changes to r8188eu] Signed-off-by: Ben Hutchings --- diff --git a/drivers/staging/rtl8712/rtl871x_recv.c b/drivers/staging/rtl8712/rtl871x_recv.c index 4cc68d1b5069..3b4a6617a5f2 100644 --- 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_frame *precvframe) /* 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);