netfilter: x_tables: misuse of try_then_request_module

Since xt_find_match() returns ERR_PTR(xx) on error not NULL,
the macro try_then_request_module won't work correctly here.
The macro expects its first argument will be zero if condition
fails. But ERR_PTR(-ENOENT) is not zero.

The correct solution is to propagate the error value
back.

Found by inspection, and compile tested only.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 15 insertions, 7 deletions

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 0a77d2ff2154..271eed32a6a1 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -183,7 +183,7 @@ EXPORT_SYMBOL(xt_unregister_matches);
 /*
  * These are weird, but module loading must not be done with mutex
  * held (since they will register), and we have to have a single
- * function to use try_then_request_module().
+ * function to use.
  */
 
 /* Find match, grabs ref.  Returns ERR_PTR() on error. */
@@ -221,9 +221,13 @@ xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision)
 {
         struct xt_match *match;
 
-        match = try_then_request_module(xt_find_match(nfproto, name, revision),
-                                        "%st_%s", xt_prefix[nfproto], name);
-        return (match != NULL) ? match : ERR_PTR(-ENOENT);
+        match = xt_find_match(nfproto, name, revision);
+        if (IS_ERR(match)) {
+                request_module("%st_%s", xt_prefix[nfproto], name);
+                match = xt_find_match(nfproto, name, revision);
+        }
+
+        return match;
 }
 EXPORT_SYMBOL_GPL(xt_request_find_match);
 
@@ -261,9 +265,13 @@ struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
 {
         struct xt_target *target;
 
-        target = try_then_request_module(xt_find_target(af, name, revision),
-                                         "%st_%s", xt_prefix[af], name);
-        return (target != NULL) ? target : ERR_PTR(-ENOENT);
+        target = xt_find_target(af, name, revision);
+        if (IS_ERR(target)) {
+                request_module("%st_%s", xt_prefix[af], name);
+                target = xt_find_target(af, name, revision);
+        }
+
+        return target;
 }
 EXPORT_SYMBOL_GPL(xt_request_find_target);