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| author | Christoph Schulz <develop@kristov.de> | 2014-07-17 00:10:29 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-07-17 10:42:06 +0400 |
| commit | cc25eaae238ddd693aa5eaa73e565d8ff4915f6e (patch) | |
| tree | 629a02ffbc4e6568d6989b9076b42cf360c5c2c3 /drivers/isdn | |
| parent | 858e6c321065344339906672bccd0eafe9622258 (diff) | |
| download | linux-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')
| -rw-r--r-- | drivers/isdn/i4l/isdn_ppp.c | 20 |
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; |