From: Taehee Yoo ap420073@gmail.com
[ Upstream commit 54451f60c8fa061af9051a53be9786393947367c ]
When IDLETIMER rule is added, sysfs file is created under /sys/class/xt_idletimer/timers/ But some label name shouldn't be used. ".", "..", "power", "uevent", "subsystem", etc... So that sysfs filename checking routine is needed.
test commands: %iptables -I INPUT -j IDLETIMER --timeout 1 --label "power"
splat looks like: [95765.423132] sysfs: cannot create duplicate filename '/devices/virtual/xt_idletimer/timers/power' [95765.433418] CPU: 0 PID: 8446 Comm: iptables Not tainted 4.19.0-rc6+ #20 [95765.449755] Call Trace: [95765.449755] dump_stack+0xc9/0x16b [95765.449755] ? show_regs_print_info+0x5/0x5 [95765.449755] sysfs_warn_dup+0x74/0x90 [95765.449755] sysfs_add_file_mode_ns+0x352/0x500 [95765.449755] sysfs_create_file_ns+0x179/0x270 [95765.449755] ? sysfs_add_file_mode_ns+0x500/0x500 [95765.449755] ? idletimer_tg_checkentry+0x3e5/0xb1b [xt_IDLETIMER] [95765.449755] ? rcu_read_lock_sched_held+0x114/0x130 [95765.449755] ? __kmalloc_track_caller+0x211/0x2b0 [95765.449755] ? memcpy+0x34/0x50 [95765.449755] idletimer_tg_checkentry+0x4e2/0xb1b [xt_IDLETIMER] [ ... ]
Fixes: 0902b469bd25 ("netfilter: xtables: idletimer target implementation") Signed-off-by: Taehee Yoo ap420073@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/xt_IDLETIMER.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c index 5ee859193783..25453a16385e 100644 --- a/net/netfilter/xt_IDLETIMER.c +++ b/net/netfilter/xt_IDLETIMER.c @@ -116,6 +116,22 @@ static void idletimer_tg_expired(struct timer_list *t) schedule_work(&timer->work); }
+static int idletimer_check_sysfs_name(const char *name, unsigned int size) +{ + int ret; + + ret = xt_check_proc_name(name, size); + if (ret < 0) + return ret; + + if (!strcmp(name, "power") || + !strcmp(name, "subsystem") || + !strcmp(name, "uevent")) + return -EINVAL; + + return 0; +} + static int idletimer_tg_create(struct idletimer_tg_info *info) { int ret; @@ -126,6 +142,10 @@ static int idletimer_tg_create(struct idletimer_tg_info *info) goto out; }
+ ret = idletimer_check_sysfs_name(info->label, sizeof(info->label)); + if (ret < 0) + goto out_free_timer; + sysfs_attr_init(&info->timer->attr.attr); info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL); if (!info->timer->attr.attr.name) {