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authorChristoph Schulz <develop@kristov.de>2014-07-17 00:10:29 +0400
committerDavid S. Miller <davem@davemloft.net>2014-07-17 10:42:06 +0400
commitcc25eaae238ddd693aa5eaa73e565d8ff4915f6e (patch)
tree629a02ffbc4e6568d6989b9076b42cf360c5c2c3 /drivers/isdn/i4l
parent858e6c321065344339906672bccd0eafe9622258 (diff)
downloadlinux-cc25eaae238ddd693aa5eaa73e565d8ff4915f6e.tar.xz
net: ppp: fix creating PPP pass and active filters
Commit 568f194e8bd16c353ad50f9ab95d98b20578a39d ("net: ppp: use sk_unattached_filter api") inadvertently changed the logic when setting PPP pass and active filters. 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 original code in ppp_ioctl() (or isdn_ppp_ioctl(), resp.) handling PPPIOCSPASS and PPPIOCSACTIVE allowed to remove a pass/active filter previously set by using a filter of length zero. However, with the new code this is not possible anymore as this case is not explicitly checked for, which leads to passing NULL as a filter to sk_unattached_filter_create(). This results in returning EINVAL to the caller. Additionally, the variables ppp->pass_filter and ppp->active_filter (or is->pass_filter and is->active_filter, resp.) are not reset to NULL, although the filters they point to may have been destroyed by sk_unattached_filter_destroy(), so in this EINVAL case dangling pointers are left behind (provided the pointers were previously non-NULL). This patch corrects both problems by checking whether the filter passed is empty or non-empty, and prevents sk_unattached_filter_create() from being called in the first case. Moreover, the pointers are always reset to NULL as soon as sk_unattached_filter_destroy() returns. Signed-off-by: Christoph Schulz <develop@kristov.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn/i4l')
-rw-r--r--drivers/isdn/i4l/isdn_ppp.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index a333b7f798d1..62f0688d45a5 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -638,9 +638,15 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
fprog.len = len;
fprog.filter = code;
- if (is->pass_filter)
+ if (is->pass_filter) {
sk_unattached_filter_destroy(is->pass_filter);
- err = sk_unattached_filter_create(&is->pass_filter, &fprog);
+ is->pass_filter = NULL;
+ }
+ if (fprog.filter != NULL)
+ err = sk_unattached_filter_create(&is->pass_filter,
+ &fprog);
+ else
+ err = 0;
kfree(code);
return err;
@@ -657,9 +663,15 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
fprog.len = len;
fprog.filter = code;
- if (is->active_filter)
+ if (is->active_filter) {
sk_unattached_filter_destroy(is->active_filter);
- err = sk_unattached_filter_create(&is->active_filter, &fprog);
+ is->active_filter = NULL;
+ }
+ if (fprog.filter != NULL)
+ err = sk_unattached_filter_create(&is->active_filter,
+ &fprog);
+ else
+ err = 0;
kfree(code);
return err;