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Subject[PATCH] netfilter: nf_flow_table_offload: Correct memcpy size for flow_overload_mangle
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/ 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 <>
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
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->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 *
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