From 5e401ea71676bd7c82ce44eb663fec7678ccffdd Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 22 Dec 2020 23:23:56 +0100 Subject: [PATCH] netfilter: xt_RATEEST: reject non-null terminated string from userspace commit 6cb56218ad9e580e519dcd23bfb3db08d8692e5a upstream. syzbot reports: detected buffer overflow in strlen [..] Call Trace: strlen include/linux/string.h:325 [inline] strlcpy include/linux/string.h:348 [inline] xt_rateest_tg_checkentry+0x2a5/0x6b0 net/netfilter/xt_RATEEST.c:143 strlcpy assumes src is a c-string. Check info->name before its used. Reported-by: syzbot+e86f7c428c8c50db65b4@syzkaller.appspotmail.com Fixes: 5859034d7eb8793 ("[NETFILTER]: x_tables: add RATEEST target") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/xt_RATEEST.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netfilter/xt_RATEEST.c b/net/netfilter/xt_RATEEST.c index 2236455b10a3..182c1285b4ad 100644 --- a/net/netfilter/xt_RATEEST.c +++ b/net/netfilter/xt_RATEEST.c @@ -115,6 +115,9 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) } cfg; int ret; + if (strnlen(info->name, sizeof(est->name)) >= sizeof(est->name)) + return -ENAMETOOLONG; + net_get_random_once(&jhash_rnd, sizeof(jhash_rnd)); mutex_lock(&xn->hash_lock);