enic: Avoid false positive under FORTIFY_SOURCE

FORTIFY_SOURCE has been ignoring 0-sized destinations while the kernel
code base has been converted to flexible arrays. In order to enforce
the 0-sized destinations (e.g. with __counted_by), the remaining 0-sized
destinations need to be handled. Unfortunately, struct vic_provinfo
resists full conversion, as it contains a flexible array of flexible
arrays, which is only possible with the 0-sized fake flexible array.

Use unsafe_memcpy() to avoid future false positives under
CONFIG_FORTIFY_SOURCE.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/cisco/enic/vnic_vic.c b/drivers/net/ethernet/cisco/enic/vnic_vic.c
index 20fcb20b42edee5129fcf6e5edde9f3a0ecd2764..66b57783533897e6399ec12505441004646b8ebc 100644 (file)
--- a/drivers/net/ethernet/cisco/enic/vnic_vic.c
+++ b/drivers/net/ethernet/cisco/enic/vnic_vic.c
@@ -49,7 +49,8 @@ int vic_provinfo_add_tlv(struct vic_provinfo *vp, u16 type, u16 length,
 
        tlv->type = htons(type);
        tlv->length = htons(length);
-       memcpy(tlv->value, value, length);
+       unsafe_memcpy(tlv->value, value, length,
+                     /* Flexible array of flexible arrays */);
 
        vp->num_tlvs = htonl(ntohl(vp->num_tlvs) + 1);
        vp->length = htonl(ntohl(vp->length) +