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Date: Fri, 11 Apr 2014 10:35:34 +0200 From: Mateusz Guzik <mguzik@...hat.com> To: "Wang, Xiaoming" <xiaoming.wang@...el.com> Cc: davem@...emloft.net, kuznet@....inr.ac.ru, jmorris@...ei.org, yoshfuji@...ux-ipv6.org, kaber@...sh.net, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, chuansheng.liu@...el.com, dongxing.zhang@...el.com, pmatouse@...hat.com Subject: Re: [PATCH] net: ipv4: current group_info should be put after using. 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. 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 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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