From 33ffa638a627c467a817a53295fc8ed9de9e5d5f Mon Sep 17 00:00:00 2001
From: Xiu Jianfeng <xiujianfeng@huawei.com>
Date: Thu, 8 Dec 2022 11:15:27 +0000
Subject: [PATCH] ftrace: Fix null pointer dereference in ftrace_add_mod()
stable inclusion
from stable-v4.19.267
commit b5bfc61f541d3f092b13dedcfe000d86eb8e133c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I63UEU
CVE: NA
--------------------------------
commit 19ba6c8af9382c4c05dc6a0a79af3013b9a35cd0 upstream.
The @ftrace_mod is allocated by kzalloc(), so both the members {prev,next}
of @ftrace_mode->list are NULL, it's not a valid state to call list_del().
If kstrdup() for @ftrace_mod->{func|module} fails, it goes to @out_free
tag and calls free_ftrace_mod() to destroy @ftrace_mod, then list_del()
will write prev->next and next->prev, where null pointer dereference
happens.
BUG: kernel NULL pointer dereference, address: 0000000000000008
Oops: 0002 [#1] PREEMPT SMP NOPTI
Call Trace:
<TASK>
ftrace_mod_callback+0x20d/0x220
? do_filp_open+0xd9/0x140
ftrace_process_regex.isra.51+0xbf/0x130
ftrace_regex_write.isra.52.part.53+0x6e/0x90
vfs_write+0xee/0x3a0
? __audit_filter_op+0xb1/0x100
? auditd_test_task+0x38/0x50
ksys_write+0xa5/0xe0
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Kernel panic - not syncing: Fatal exception
So call INIT_LIST_HEAD() to initialize the list member to fix this issue.
Link: https://lkml.kernel.org/r/20221116015207.30858-1-xiujianfeng@huawei.com
Cc: stable@vger.kernel.org
Fixes: 673feb9d76ab ("ftrace: Add :mod: caching infrastructure to trace_array")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
---
kernel/trace/ftrace.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e5dd0a5aa088..3962c6be47f5 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1331,6 +1331,7 @@ static int ftrace_add_mod(struct trace_array *tr,
if (!ftrace_mod)
return -ENOMEM;
+ INIT_LIST_HEAD(&ftrace_mod->list);
ftrace_mod->func = kstrdup(func, GFP_KERNEL);
ftrace_mod->module = kstrdup(module, GFP_KERNEL);
ftrace_mod->enable = enable;
--
GitLab