From: Wang ShaoBo <bobo.shaobowang@huawei.com>
Date: Thu, 28 Jan 2021 20:44:27 +0800
Subject: kretprobe: Avoid re-registration of the same kretprobe earlier
Git-commit: 0188b87899ffc4a1d36a0badbe77d56c92fd91dc
Patch-mainline: v5.11-rc7
References: git-fixes
Our system encountered a re-init error when re-registering same kretprobe,
where the kretprobe_instance in rp->free_instances is illegally accessed
after re-init.
Implementation to avoid re-registration has been introduced for kprobe
before, but lags for register_kretprobe(). We must check if kprobe has
been re-registered before re-initializing kretprobe, otherwise it will
destroy the data struct of kretprobe registered, which can lead to memory
leak, system crash, also some unexpected behaviors.
We use check_kprobe_rereg() to check if kprobe has been re-registered
before running register_kretprobe()'s body, for giving a warning message
and terminate registration process.
Link: https://lkml.kernel.org/r/20210128124427.2031088-1-bobo.shaobowang@huawei.com
Cc: stable@vger.kernel.org
Fixes: 1f0ab40976460 ("kprobes: Prevent re-registration of the same kprobe")
[ The above commit should have been done for kretprobes too ]
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@linux.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Petr Pavlu <petr.pavlu@suse.com>
---
kernel/kprobes.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1a5bc321e0a5..d5a3eb74a657 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1994,6 +1994,10 @@ int register_kretprobe(struct kretprobe *rp)
if (!function_offset_within_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset))
return -EINVAL;
+ /* If only rp->kp.addr is specified, check reregistering kprobes */
+ if (rp->kp.addr && check_kprobe_rereg(&rp->kp))
+ return -EINVAL;
+
if (kretprobe_blacklist_size) {
addr = kprobe_addr(&rp->kp);
if (IS_ERR(addr))