Messages in this thread | | | Date | Wed, 30 Sep 2009 15:38:12 +0200 | From | Hannes Eder <> | Subject | Re: [PATCH] ipvs: Add boundary check on ioctl arguments |
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[cc: +Simon Horman]
Arjan van de Ven wrote: > From 761a182f96b3707e1fee44e1079ba227e48745d1 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..3c52796 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 > MAX_ARG_LEN) > + 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];
can MAX_ARG_LEN be used here?
> 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 > 128)
I think it's better to use 'copylen > sizeof(arg)' here.
> + return -EINVAL; > + > + if (copy_from_user(arg, user, copylen) != 0) > return -EFAULT; > > if (mutex_lock_interruptible(&__ip_vs_mutex))
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