lkml.org 
[lkml]   [2014]   [Apr]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] net: ipv4: current group_info should be put after using.
On Fri, Apr 11, 2014 at 10:35:33AM +0200, Mateusz Guzik wrote:
> On Fri, Apr 11, 2014 at 01:37:08PM -0400, Wang, Xiaoming wrote:
> > There is a memory leak in ping. Current group_info had been got in
> > ping_init_sock and group_info->usage increased.
> > But the usage hasn't decreased anywhere in ping.
> > This will make this group_info never freed and cause memory leak.
> >
>
> Memory leak is only one of possible side-effects, thus I believe commit
> message should be adjusted.
>
> This is a typical refcount leak exploitable by unprivileged users, so
> side effects can range from nothing through memory leaks and crashes to
> possibly privilege escalation.
>
> That said losing ' and cause memory leak' from your commit message
> would be fine in my opinion.
>

Huh, not sure why I wrote that last sentence, it does not make much
sense. Sorry.

There is a pending CVE request for this bug:
http://seclists.org/oss-sec/2014/q2/97

The bug was introduced with:
commit c319b4d76b9e583a5d88d6bf190e079c4e43213d
Author: Vasiliy Kulikov <segoon@openwall.com>
Date: Fri May 13 10:01:00 2011 +0000

net: ipv4: add IPPROTO_ICMP socket kind

starting with 3.0 kernel.


> See also a nit below.
>
> > ---
> > net/ipv4/ping.c | 11 ++++++++---
> > 1 files changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
> > index f4b19e5..2af7b1f 100644
> > --- a/net/ipv4/ping.c
> > +++ b/net/ipv4/ping.c
> > @@ -255,23 +255,28 @@ int ping_init_sock(struct sock *sk)
> > struct group_info *group_info = get_current_groups();
> > int i, j, count = group_info->ngroups;
> > kgid_t low, high;
> > + int ret = 0;
> >
> > inet_get_ping_group_range_net(net, &low, &high);
> > if (gid_lte(low, group) && gid_lte(group, high))
> > - return 0;
> > + goto out_release_group;
> >
>
> Since group_info is not even used here maybe it would be better to leave
> return 0 as it is and call get_current_groups before the loop?
>
> > for (i = 0; i < group_info->nblocks; i++) {
> > int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
> > for (j = 0; j < cp_count; j++) {
> > kgid_t gid = group_info->blocks[i][j];
> > if (gid_lte(low, gid) && gid_lte(gid, high))
> > - return 0;
> > + goto out_release_group;
> > }
> >
> > count -= cp_count;
> > }
> >
> > - return -EACCES;
> > + ret = -EACCES;
> > +
> > +out_release_group:
> > + put_group_info(group_info);
> > + return ret;
> > }
> > EXPORT_SYMBOL_GPL(ping_init_sock);
> >
>
> --
> Mateusz Guzik

--
Mateusz Guzik


\
 
 \ /
  Last update: 2014-04-11 15:41    [W:0.039 / U:0.244 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site