From: "Gustavo A. R. Silva" gustavoars@kernel.org
[ Upstream commit 323e0cb473e2a8706ff162b6b4f4fa16023c9ba7 ]
Fix the following out-of-bounds warnings:
net/core/flow_dissector.c: In function '__skb_flow_dissect':
net/core/flow_dissector.c:1104:4: warning: 'memcpy' offset [24, 39] from the object at '<unknown>' is out of the bounds of referenced subobject 'saddr' with type 'struct in6_addr' at offset 8 [-Warray-bounds]
1104 | memcpy(&key_addrs->v6addrs, &iph->saddr, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1105 | sizeof(key_addrs->v6addrs)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/ipv6.h:5, from net/core/flow_dissector.c:6: include/uapi/linux/ipv6.h:133:18: note: subobject 'saddr' declared here 133 | struct in6_addr saddr; | ^~~~~
net/core/flow_dissector.c:1059:4: warning: 'memcpy' offset [16, 19] from the object at '<unknown>' is out of the bounds of referenced subobject 'saddr' with type 'unsigned int' at offset 12 [-Warray-bounds]
1059 | memcpy(&key_addrs->v4addrs, &iph->saddr, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1060 | sizeof(key_addrs->v4addrs)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/ip.h:17, from net/core/flow_dissector.c:5: include/uapi/linux/ip.h:103:9: note: subobject 'saddr' declared here 103 | __be32 saddr; | ^~~~~
The problem is that the original code is trying to copy data into a couple of struct members adjacent to each other in a single call to memcpy(). So, the compiler legitimately complains about it. As these are just a couple of members, fix this by copying each one of them in separate calls to memcpy().
This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy().
Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot lkp@intel.com Link: https://lore.kernel.org/lkml/d5ae2e65-1f18-2577-246f-bada7eee6ccd@intel.com/ Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/flow_dissector.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 3ed7c98a98e1..6076c75706d0 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1056,8 +1056,10 @@ bool __skb_flow_dissect(const struct net *net, FLOW_DISSECTOR_KEY_IPV4_ADDRS, target_container);
- memcpy(&key_addrs->v4addrs, &iph->saddr, - sizeof(key_addrs->v4addrs)); + memcpy(&key_addrs->v4addrs.src, &iph->saddr, + sizeof(key_addrs->v4addrs.src)); + memcpy(&key_addrs->v4addrs.dst, &iph->daddr, + sizeof(key_addrs->v4addrs.dst)); key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; }
@@ -1101,8 +1103,10 @@ bool __skb_flow_dissect(const struct net *net, FLOW_DISSECTOR_KEY_IPV6_ADDRS, target_container);
- memcpy(&key_addrs->v6addrs, &iph->saddr, - sizeof(key_addrs->v6addrs)); + memcpy(&key_addrs->v6addrs.src, &iph->saddr, + sizeof(key_addrs->v6addrs.src)); + memcpy(&key_addrs->v6addrs.dst, &iph->daddr, + sizeof(key_addrs->v6addrs.dst)); key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; }