From: Cong Wang Date: Mon, 3 Feb 2020 04:30:53 +0000 (-0800) Subject: netfilter: xt_hashlimit: limit the max size of hashtable X-Git-Tag: v5.10.7~3189^2~18^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8d0015a7ab76b8b1e89a3e5f5710a6e5103f2dd5;p=platform%2Fkernel%2Flinux-rpi.git netfilter: xt_hashlimit: limit the max size of hashtable The user-specified hashtable size is unbound, this could easily lead to an OOM or a hung task as we hold the global mutex while allocating and initializing the new hashtable. Add a max value to cap both cfg->size and cfg->max, as suggested by Florian. Reported-and-tested-by: syzbot+adf6c6c2be1c3a718121@syzkaller.appspotmail.com Signed-off-by: Cong Wang Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index cc475a6..7a2c4b8 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -837,6 +837,8 @@ hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3); } +#define HASHLIMIT_MAX_SIZE 1048576 + static int hashlimit_mt_check_common(const struct xt_mtchk_param *par, struct xt_hashlimit_htable **hinfo, struct hashlimit_cfg3 *cfg, @@ -847,6 +849,14 @@ static int hashlimit_mt_check_common(const struct xt_mtchk_param *par, if (cfg->gc_interval == 0 || cfg->expire == 0) return -EINVAL; + if (cfg->size > HASHLIMIT_MAX_SIZE) { + cfg->size = HASHLIMIT_MAX_SIZE; + pr_info_ratelimited("size too large, truncated to %u\n", cfg->size); + } + if (cfg->max > HASHLIMIT_MAX_SIZE) { + cfg->max = HASHLIMIT_MAX_SIZE; + pr_info_ratelimited("max too large, truncated to %u\n", cfg->max); + } if (par->family == NFPROTO_IPV4) { if (cfg->srcmask > 32 || cfg->dstmask > 32) return -EINVAL;