[PATCH] net: filter: fix possible memory leak in __sk_prepare_filter()

[Leon Yu <chianglungyu@gmail.com>]

__sk_prepare_filter() was reworked in commit bd4cf0ed3 (net: filter:
rework/optimize internal BPF interpreter's instruction set) so that it should
have uncharged memory once things went wrong. However that work isn't complete.
Error is handled only in __sk_migrate_filter() while memory can still leak in
the error path right after sk_chk_filter().

Signed-off-by: Leon Yu <chianglungyu@gmail.com>
---
 net/core/filter.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 9d79ca0..4aec7b9 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1559,8 +1559,13 @@ static struct sk_filter *__sk_prepare_filter(struct sk_filter *fp,
 	fp->jited = 0;
 
 	err = sk_chk_filter(fp->insns, fp->len);
-	if (err)
+	if (err) {
+		if (sk != NULL)
+			sk_filter_uncharge(sk, fp);
+		else
+			kfree(fp);
 		return ERR_PTR(err);
+	}
 
 	/* Probe if we can JIT compile the filter and if so, do
 	 * the compilation of the filter.
-- 
1.9.3