git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From e0d75267f59d7084e0468bd68beeb1bf9c71d7c0 Mon Sep 17 00:00:00 2001
   2 From: Shang XiaoJing <shangxiaojing@huawei.com>
   3 Date: Fri, 18 Nov 2022 10:15:33 +0900
   4 Subject: tracing: kprobe: Fix potential null-ptr-deref on trace_event_file in kprobe_event_gen_test_exit()
   5
   6 From: Shang XiaoJing <shangxiaojing@huawei.com>
   7
   8 commit e0d75267f59d7084e0468bd68beeb1bf9c71d7c0 upstream.
   9
  10 When trace_get_event_file() failed, gen_kretprobe_test will be assigned
  11 as the error code. If module kprobe_event_gen_test is removed now, the
  12 null pointer dereference will happen in kprobe_event_gen_test_exit().
  13 Check if gen_kprobe_test or gen_kretprobe_test is error code or NULL
  14 before dereference them.
  15
  16 BUG: kernel NULL pointer dereference, address: 0000000000000012
  17 PGD 0 P4D 0
  18 Oops: 0000 [#1] SMP PTI
  19 CPU: 3 PID: 2210 Comm: modprobe Not tainted
  20 6.1.0-rc1-00171-g2159299a3b74-dirty #217
  21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
  22 rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
  23 RIP: 0010:kprobe_event_gen_test_exit+0x1c/0xb5 [kprobe_event_gen_test]
  24 Code: Unable to access opcode bytes at 0xffffffff9ffffff2.
  25 RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246
  26 RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000
  27 RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c
  28 RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0
  29 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800
  30 R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000
  31 FS:  00007f56b75be540(0000) GS:ffff88813bc00000(0000)
  32 knlGS:0000000000000000
  33 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  34 CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0
  35 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  36 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  37 Call Trace:
  38  <TASK>
  39  __x64_sys_delete_module+0x206/0x380
  40  ? lockdep_hardirqs_on_prepare+0xd8/0x190
  41  ? syscall_enter_from_user_mode+0x1c/0x50
  42  do_syscall_64+0x3f/0x90
  43  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  44
  45 Link: https://lore.kernel.org/all/20221108015130.28326-2-shangxiaojing@huawei.com/
  46
  47 Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
  48 Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
  49 Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
  50 Cc: stable@vger.kernel.org
  51 Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
  52 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  53 ---
  54  kernel/trace/kprobe_event_gen_test.c |   44 ++++++++++++++++++++++-------------
  55  1 file changed, 28 insertions(+), 16 deletions(-)
  56
  57 --- a/kernel/trace/kprobe_event_gen_test.c
  58 +++ b/kernel/trace/kprobe_event_gen_test.c
  59 @@ -73,6 +73,10 @@ static struct trace_event_file *gen_kret
  60  #define KPROBE_GEN_TEST_ARG3   NULL
  61  #endif
  62
  63 +static bool trace_event_file_is_valid(struct trace_event_file *input)
  64 +{
  65 +       return input && !IS_ERR(input);
  66 +}
  67
  68  /*
  69   * Test to make sure we can create a kprobe event, then add more
  70 @@ -217,10 +221,12 @@ static int __init kprobe_event_gen_test_
  71
  72         ret = test_gen_kretprobe_cmd();
  73         if (ret) {
  74 -               WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
  75 -                                                 "kprobes",
  76 -                                                 "gen_kretprobe_test", false));
  77 -               trace_put_event_file(gen_kretprobe_test);
  78 +               if (trace_event_file_is_valid(gen_kretprobe_test)) {
  79 +                       WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
  80 +                                                         "kprobes",
  81 +                                                         "gen_kretprobe_test", false));
  82 +                       trace_put_event_file(gen_kretprobe_test);
  83 +               }
  84                 WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
  85         }
  86
  87 @@ -229,24 +235,30 @@ static int __init kprobe_event_gen_test_
  88
  89  static void __exit kprobe_event_gen_test_exit(void)
  90  {
  91 -       /* Disable the event or you can't remove it */
  92 -       WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
  93 -                                         "kprobes",
  94 -                                         "gen_kprobe_test", false));
  95 +       if (trace_event_file_is_valid(gen_kprobe_test)) {
  96 +               /* Disable the event or you can't remove it */
  97 +               WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
  98 +                                                 "kprobes",
  99 +                                                 "gen_kprobe_test", false));
 100 +
 101 +               /* Now give the file and instance back */
 102 +               trace_put_event_file(gen_kprobe_test);
 103 +       }
 104
 105 -       /* Now give the file and instance back */
 106 -       trace_put_event_file(gen_kprobe_test);
 107
 108         /* Now unregister and free the event */
 109         WARN_ON(kprobe_event_delete("gen_kprobe_test"));
 110
 111 -       /* Disable the event or you can't remove it */
 112 -       WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
 113 -                                         "kprobes",
 114 -                                         "gen_kretprobe_test", false));
 115 +       if (trace_event_file_is_valid(gen_kretprobe_test)) {
 116 +               /* Disable the event or you can't remove it */
 117 +               WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
 118 +                                                 "kprobes",
 119 +                                                 "gen_kretprobe_test", false));
 120 +
 121 +               /* Now give the file and instance back */
 122 +               trace_put_event_file(gen_kretprobe_test);
 123 +       }
 124
 125 -       /* Now give the file and instance back */
 126 -       trace_put_event_file(gen_kretprobe_test);
 127
 128         /* Now unregister and free the event */
 129         WARN_ON(kprobe_event_delete("gen_kretprobe_test"));