The sizes for memcpy in flow_offload_mangle don't match the source variables, leading to overflow errors on some build configurations: In function 'memcpy', inlined from 'flow_offload_mangle' at net/netfilter/nf_flow_table_offload.c:112:2, inlined from 'flow_offload_port_dnat' at net/netfilter/nf_flow_table_offload.c:373:2, inlined from 'nf_flow_rule_route_ipv4' at net/netfilter/nf_flow_table_offload.c:424:3: ./include/linux/string.h:376:4: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter 376 | __read_overflow2(); | ^~~~~~~~~~~~~~~~~~ make[2]: *** [scripts/Makefile.build:266: net/netfilter/nf_flow_table_offload.o] Error 1 Fix this by using the corresponding type. Fixes: c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support") Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx> --- Seen on a Fedora powerpc little endian build with -O3 but it looks like it is correctly catching an error with doing a memcpy outside the source variable. --- net/netfilter/nf_flow_table_offload.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index c54c9a6cc981..526f894d0bdb 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -108,8 +108,8 @@ static void flow_offload_mangle(struct flow_action_entry *entry, entry->id = FLOW_ACTION_MANGLE; entry->mangle.htype = htype; entry->mangle.offset = offset; - memcpy(&entry->mangle.mask, mask, sizeof(u32)); - memcpy(&entry->mangle.val, value, sizeof(u32)); + memcpy(&entry->mangle.mask, mask, sizeof(u8)); + memcpy(&entry->mangle.val, value, sizeof(u8)); } static inline struct flow_action_entry * -- 2.21.0