diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-03-12 18:14:42 -0500 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-03-20 13:41:04 +0100 |
| commit | 8039ab43eeac029a9c47c0411918ea82c9ce87cd (patch) | |
| tree | 011831e1970bab8b521125d2be88c5694ab47922 /net/netfilter | |
| parent | d719e3f21cf91d3f82bd827d46199ba41af2f73a (diff) | |
| download | linux-8039ab43eeac029a9c47c0411918ea82c9ce87cd.tar.bz2 | |
netfilter: cttimeout: remove VLA usage
In preparation to enabling -Wvla, remove VLA and replace it
with dynamic memory allocation.
>From a security viewpoint, the use of Variable Length Arrays can be
a vector for stack overflow attacks. Also, in general, as the code
evolves it is easy to lose track of how big a VLA can get. Thus, we
can end up having segfaults that are hard to debug.
Also, fixed as part of the directive to remove all VLAs from
the kernel: https://lkml.org/lkml/2018/3/7/621
While at it, remove likely() notation which is not necessary from the
control plane code.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/nfnetlink_cttimeout.c | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c index 95b04702a655..9ee5fa551fa6 100644 --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -51,19 +51,27 @@ ctnl_timeout_parse_policy(void *timeouts, const struct nf_conntrack_l4proto *l4proto, struct net *net, const struct nlattr *attr) { + struct nlattr **tb; int ret = 0; - if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) { - struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1]; + if (!l4proto->ctnl_timeout.nlattr_to_obj) + return 0; - ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, - attr, l4proto->ctnl_timeout.nla_policy, - NULL); - if (ret < 0) - return ret; + tb = kcalloc(l4proto->ctnl_timeout.nlattr_max + 1, sizeof(*tb), + GFP_KERNEL); - ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts); - } + if (!tb) + return -ENOMEM; + + ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, attr, + l4proto->ctnl_timeout.nla_policy, NULL); + if (ret < 0) + goto err; + + ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts); + +err: + kfree(tb); return ret; } |