lkml.org 
[lkml]   [2022]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 1/2] tracing: kprobe: Fix potential null-ptr-deref on trace_event_file in kprobe_event_gen_test_exit()
Date
When trace_get_event_file() failed, gen_kretprobe_test will be assigned
as the error code. If module kprobe_event_gen_test is removed now, the
null pointer dereference will happen in kprobe_event_gen_test_exit().
Check if gen_kprobe_test or gen_kretprobe_test is error code or NULL
before dereference them.

BUG: kernel NULL pointer dereference, address: 0000000000000012
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 3 PID: 2210 Comm: modprobe Not tainted
6.1.0-rc1-00171-g2159299a3b74-dirty #217
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:kprobe_event_gen_test_exit+0x1c/0xb5 [kprobe_event_gen_test]
Code: Unable to access opcode bytes at 0xffffffff9ffffff2.
RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246
RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000
RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c
RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800
R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f56b75be540(0000) GS:ffff88813bc00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__x64_sys_delete_module+0x206/0x380
? lockdep_hardirqs_on_prepare+0xd8/0x190
? syscall_enter_from_user_mode+0x1c/0x50
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
---
changes in v2:
- add Cc tag to stable@vger.kernel.org.
---
kernel/trace/kprobe_event_gen_test.c | 44 ++++++++++++++++++----------
1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
index d81f7c51025c..1c98fafcf333 100644
--- a/kernel/trace/kprobe_event_gen_test.c
+++ b/kernel/trace/kprobe_event_gen_test.c
@@ -73,6 +73,10 @@ static struct trace_event_file *gen_kretprobe_test;
#define KPROBE_GEN_TEST_ARG3 NULL
#endif

+static bool trace_event_file_is_valid(struct trace_event_file *input)
+{
+ return input && !IS_ERR(input);
+}

/*
* Test to make sure we can create a kprobe event, then add more
@@ -217,10 +221,12 @@ static int __init kprobe_event_gen_test_init(void)

ret = test_gen_kretprobe_cmd();
if (ret) {
- WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
- "kprobes",
- "gen_kretprobe_test", false));
- trace_put_event_file(gen_kretprobe_test);
+ if (trace_event_file_is_valid(gen_kretprobe_test)) {
+ WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+ "kprobes",
+ "gen_kretprobe_test", false));
+ trace_put_event_file(gen_kretprobe_test);
+ }
WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
}

@@ -229,24 +235,30 @@ static int __init kprobe_event_gen_test_init(void)

static void __exit kprobe_event_gen_test_exit(void)
{
- /* Disable the event or you can't remove it */
- WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
- "kprobes",
- "gen_kprobe_test", false));
+ if (trace_event_file_is_valid(gen_kprobe_test)) {
+ /* Disable the event or you can't remove it */
+ WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
+ "kprobes",
+ "gen_kprobe_test", false));
+
+ /* Now give the file and instance back */
+ trace_put_event_file(gen_kprobe_test);
+ }

- /* Now give the file and instance back */
- trace_put_event_file(gen_kprobe_test);

/* Now unregister and free the event */
WARN_ON(kprobe_event_delete("gen_kprobe_test"));

- /* Disable the event or you can't remove it */
- WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
- "kprobes",
- "gen_kretprobe_test", false));
+ if (trace_event_file_is_valid(gen_kretprobe_test)) {
+ /* Disable the event or you can't remove it */
+ WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+ "kprobes",
+ "gen_kretprobe_test", false));
+
+ /* Now give the file and instance back */
+ trace_put_event_file(gen_kretprobe_test);
+ }

- /* Now give the file and instance back */
- trace_put_event_file(gen_kretprobe_test);

/* Now unregister and free the event */
WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
--
2.17.1
\
 
 \ /
  Last update: 2022-11-08 02:53    [W:3.112 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site