Linux Ethernet Bridging - Feb 2019 - [Bridge] [PATCH][nf-next] netfilter: convert the proto argument from u8 to u16

The proto in struct xt_match and struct xt_target is u16, when
calling xt_check_target/match, their proto argument is u8,
and will cause truncation, it is harmless to ip packet, since
ip proto is u8

if a L2 match/target has proto that is u16, will cause the check
failure.

and convert be16 to short in bridge/netfilter/ebtables.c

Signed-off-by: Zhang Yu <zhangyu31 at baidu.com>
Signed-off-by: Li RongQing <lirongqing at baidu.com>
---
 include/linux/netfilter/x_tables.h | 4 ++--
 net/bridge/netfilter/ebtables.c    | 6 +++---
 net/netfilter/x_tables.c           | 4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/netfilter/x_tables.h
b/include/linux/netfilter/x_tables.h
index 9077b3ebea08..8ba6a6227542 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -289,9 +289,9 @@ bool xt_find_jump_offset(const unsigned int *offsets,
 
 int xt_check_proc_name(const char *name, unsigned int size);
 
-int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto,
+int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int16_t proto,
 		   bool inv_proto);
-int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto,
+int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int16_t
proto,
 		    bool inv_proto);
 
 int xt_match_to_user(const struct xt_entry_match *m,
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 6693e209efe8..7bbb9b189752 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -385,7 +385,7 @@ ebt_check_match(struct ebt_entry_match *m, struct
xt_mtchk_param *par,
 	par->match     = match;
 	par->matchinfo = m->data;
 	ret = xt_check_match(par, m->match_size,
-	      e->ethproto, e->invflags & EBT_IPROTO);
+	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 	if (ret < 0) {
 		module_put(match->me);
 		return ret;
@@ -422,7 +422,7 @@ ebt_check_watcher(struct ebt_entry_watcher *w, struct
xt_tgchk_param *par,
 	par->target   = watcher;
 	par->targinfo = w->data;
 	ret = xt_check_target(par, w->watcher_size,
-	      e->ethproto, e->invflags & EBT_IPROTO);
+	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 	if (ret < 0) {
 		module_put(watcher->me);
 		return ret;
@@ -767,7 +767,7 @@ ebt_check_entry(struct ebt_entry *e, struct net *net,
 	tgpar.target   = target;
 	tgpar.targinfo = t->data;
 	ret = xt_check_target(&tgpar, t->target_size,
-	      e->ethproto, e->invflags & EBT_IPROTO);
+	      ntohs(e->ethproto), e->invflags & EBT_IPROTO);
 	if (ret < 0) {
 		module_put(target->me);
 		goto cleanup_watchers;
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 13e1ac333fa4..5b61146443ad 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -461,7 +461,7 @@ int xt_check_proc_name(const char *name, unsigned int size)
 EXPORT_SYMBOL(xt_check_proc_name);
 
 int xt_check_match(struct xt_mtchk_param *par,
-		   unsigned int size, u_int8_t proto, bool inv_proto)
+		   unsigned int size, u_int16_t proto, bool inv_proto)
 {
 	int ret;
 
@@ -984,7 +984,7 @@ bool xt_find_jump_offset(const unsigned int *offsets,
 EXPORT_SYMBOL(xt_find_jump_offset);
 
 int xt_check_target(struct xt_tgchk_param *par,
-		    unsigned int size, u_int8_t proto, bool inv_proto)
+		    unsigned int size, u_int16_t proto, bool inv_proto)
 {
 	int ret;
 
-- 
2.16.2

Li RongQing <lirongqing at baidu.com> wrote:
> The proto in struct xt_match and struct xt_target is u16, when
> calling xt_check_target/match, their proto argument is u8,
> and will cause truncation, it is harmless to ip packet, since
> ip proto is u8
> 
> if a L2 match/target has proto that is u16, will cause the check
> failure.
Yes, I don't see any ebtables matches/targets that set .proto though, so
no failure should happen in current kernel.

Otherwise, could you add an example where we hit a checkentry failure in
error?
> +int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int16_t
proto,
>  		   bool inv_proto);
I think you can use u16 instead of the old u_int16_t.

Other than that, this looks good to me, thanks.