Messages in this thread Patch in this message | | | Date | Fri, 2 Oct 2009 11:35:56 +0300 (EEST) | From | Julian Anastasov <> | Subject | Re: [PATCH] ipvs: Add boundary check on ioctl arguments |
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Hello,
On Wed, 30 Sep 2009, Arjan van de Ven wrote:
> fair enough; updated patch below
OK, you can add my signed-off line after changing 'cmd > ...MAX + 1' to 'cmd > ...MAX' at both places, nf_sockopt_ops ranges are [optmin ... optmax)
May be comments should be changed because:
- i'm not the author but after ispection we do not see any holes, we do not want users to upgrade just for this change - the cmd checks are just to help code checking tools - the len checks should help programmers (may be BUG_ON is better, user does not deserve EINVAL for wrong set_arglen/get_arglen). Checks for *len and len are not needed.
For example, for len checks this should be enough, before copy_from_user():
in do_ip_vs_get_ctl check can be BUG_ON(get_arglen[GET_CMDID(cmd)] > sizeof(arg));
in do_ip_vs_set_ctl check can be BUG_ON(set_arglen[SET_CMDID(cmd)] > sizeof(arg));
Acked-by: Julian Anastasov <ja@ssi.bg>
> >From 28ae217858e683c0c94c02219d46a9a9c87f61c6 Mon Sep 17 00:00:00 2001 > From: Arjan van de Ven <arjan@linux.intel.com> > Date: Wed, 30 Sep 2009 13:05:51 +0200 > Subject: [PATCH] ipvs: Add boundary check on ioctl arguments > > The ipvs code has a nifty system for doing the size of ioctl command copies; > it defines an array with values into which it indexes the cmd to find the > right length. > > Unfortunately, the ipvs code forgot to check if the cmd was in the range > that the array provides, allowing for an index outside of the array, > which then gives a "garbage" result into the length, which then gets > used for copying into a stack buffer. > > Fix this by adding sanity checks on these as well as the copy size. > > Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> > --- > net/netfilter/ipvs/ip_vs_ctl.c | 14 +++++++++++++- > 1 files changed, 13 insertions(+), 1 deletions(-) > > diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c > index ac624e5..7adc876 100644 > --- a/net/netfilter/ipvs/ip_vs_ctl.c > +++ b/net/netfilter/ipvs/ip_vs_ctl.c > @@ -2077,6 +2077,10 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) > if (!capable(CAP_NET_ADMIN)) > return -EPERM; > > + if (cmd < IP_VS_BASE_CTL || cmd > IP_VS_SO_SET_MAX + 1) > + return -EINVAL; > + if (len < 0 || len > sizeof(arg)) > + return -EINVAL; > if (len != set_arglen[SET_CMDID(cmd)]) { > pr_err("set_ctl: len %u != %u\n", > len, set_arglen[SET_CMDID(cmd)]); > @@ -2353,17 +2357,25 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) > { > unsigned char arg[128]; > int ret = 0; > + unsigned int copylen; > > if (!capable(CAP_NET_ADMIN)) > return -EPERM; > > + if (cmd < IP_VS_BASE_CTL || cmd > IP_VS_SO_GET_MAX + 1) > + return -EINVAL; > + > if (*len < get_arglen[GET_CMDID(cmd)]) { > pr_err("get_ctl: len %u < %u\n", > *len, get_arglen[GET_CMDID(cmd)]); > return -EINVAL; > } > > - if (copy_from_user(arg, user, get_arglen[GET_CMDID(cmd)]) != 0) > + copylen = get_arglen[GET_CMDID(cmd)]; > + if (copylen > sizeof(arg)) > + return -EINVAL; > + > + if (copy_from_user(arg, user, copylen) != 0) > return -EFAULT; > > if (mutex_lock_interruptible(&__ip_vs_mutex))
Regards
-- Julian Anastasov <ja@ssi.bg>
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