path: root/drivers/net/ppp/ppp_generic.c
diff options
authorChristoph Schulz <develop@kristov.de>2014-07-14 08:01:10 +0200
committerDavid S. Miller <davem@davemloft.net>2014-07-14 16:15:12 -0700
commit3916a3192793fd3c11f69d623ef0cdbdbf9ea10a (patch)
tree12a6418a44fe5a75b4b647639d8943e37a8aa911 /drivers/net/ppp/ppp_generic.c
parentmlx4: mark napi id for gro_skb (diff)
net: ppp: don't call sk_chk_filter twice
Commit 568f194e8bd16c353ad50f9ab95d98b20578a39d ("net: ppp: use sk_unattached_filter api") causes sk_chk_filter() to be called twice when setting a PPP pass or active filter. This applies to both the generic PPP subsystem implemented by drivers/net/ppp/ppp_generic.c and the ISDN PPP subsystem implemented by drivers/isdn/i4l/isdn_ppp.c. The first call is from within get_filter(). The second one is through the call chain ppp_ioctl() or isdn_ppp_ioctl() --> sk_unattached_filter_create() --> __sk_prepare_filter() --> sk_chk_filter() The first call from within get_filter() should be deleted as get_filter() is called just before calling sk_unattached_filter_create() later on, which eventually calls sk_chk_filter() anyway. For 3.15.x, this proposed change is a bugfix rather than a pure optimization as in that branch, sk_chk_filter() may replace filter codes by other codes which are not recognized when executing sk_chk_filter() a second time. So with 3.15.x, if sk_chk_filter() is called twice, the second invocation may yield EINVAL (this depends on the filter codes found in the filter to be set, but because the replacement is done for frequently used codes, this is almost always the case). The net effect is that setting pass and/or active PPP filters does not work anymore, since sk_unattached_filter_create() always returns EINVAL due to the second call to sk_chk_filter(), regardless whether the filter was originally sane or not. Signed-off-by: Christoph Schulz <develop@kristov.de> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ppp/ppp_generic.c')
1 files changed, 1 insertions, 7 deletions
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 91d6c1272fcf..e2f20f807de8 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -539,7 +539,7 @@ static int get_filter(void __user *arg, struct sock_filter **p)
struct sock_fprog uprog;
struct sock_filter *code = NULL;
- int len, err;
+ int len;
if (copy_from_user(&uprog, arg, sizeof(uprog)))
return -EFAULT;
@@ -554,12 +554,6 @@ static int get_filter(void __user *arg, struct sock_filter **p)
if (IS_ERR(code))
return PTR_ERR(code);
- err = sk_chk_filter(code, uprog.len);
- if (err) {
- kfree(code);
- return err;
- }
*p = code;
return uprog.len;