tracing/uprobe: Fix NULL pointer dereference in trace_uprobe_create()

PATCH In review Eiichi Tsukata 3 participants 5 messages Jun 14, 2019 – Jun 21, 2019 Tracing

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Eiichi Tsukata

author

2019-06-14 07:41 UTC #0 lore raw

PATCH 1/2 tracing/uprobe: Fix NULL pointer dereference in trace_uprobe_create()

Just like the case of commit 8b05a3a7503c ("tracing/kprobes: Fix NULL pointer dereference in trace_kprobe_create()"), writing an incorrectly formatted string to uprobe_events can trigger NULL pointer dereference.

Reporeducer:

  # echo r > /sys/kernel/debug/tracing/uprobe_events

dmesg:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 8000000079d12067 P4D 8000000079d12067 PUD 7b7ab067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 PID: 1903 Comm: bash Not tainted 5.2.0-rc3+ #15
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  RIP: 0010:strchr+0x0/0x30
  Code: c0 eb 0d 84 c9 74 18 48 83 c0 01 48 39 d0 74 0f 0f b6 0c 07 3a 0c 06 74 ea 19 c0 83 c8 01 c3 31 c0 c3 0f 1f 84 00 00 00 00 00 <0f> b6 07 89 f2 40 38 f0 75 0e eb 13 0f b6 47 01 48 83 c
  RSP: 0018:ffffb55fc0403d10 EFLAGS: 00010293

RAX: ffff993ffb793400 RBX: 0000000000000000 RCX: ffffffffa4852625
RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000000
RBP: ffffb55fc0403dd0 R08: ffff993ffb793400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff993ff9cc1668 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f30c5147700(0000) GS:ffff993ffda00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007b628000 CR4: 00000000000006f0

  Call Trace:
   trace_uprobe_create+0xe6/0xb10
   ? __kmalloc_track_caller+0xe6/0x1c0
   ? __kmalloc+0xf0/0x1d0
   ? trace_uprobe_create+0xb10/0xb10
   create_or_delete_trace_uprobe+0x35/0x90
   ? trace_uprobe_create+0xb10/0xb10
   trace_run_command+0x9c/0xb0
   trace_parse_run_command+0xf9/0x1eb
   ? probes_open+0x80/0x80
   __vfs_write+0x43/0x90
   vfs_write+0x14a/0x2a0
   ksys_write+0xa2/0x170
   do_syscall_64+0x7f/0x200
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for uprobe events")

Signed-off-by Eiichi Tsukata <[email protected]>

---
 kernel/trace/trace_uprobe.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

kernel/trace/trace_uprobe.c +10 -3

index 0d60d6856de5..7dc8ee55cf84 100644
@@ -443,10 +443,17 @@ static int trace_uprobe_create(int argc, const char **argv)
 	ret = 0;
 	ref_ctr_offset = 0;
 
-	/* argc must be >= 1 */
-	if (argv[0][0] == 'r')
+	switch (argv[0][0]) {
+	case 'r':
 		is_return = true;
-	else if (argv[0][0] != 'p' || argc < 2)
+		break;
+	case 'p':
+		break;
+	default:
+		return -ECANCELED;
+	}
+
+	if (argc < 2)
 		return -ECANCELED;
 
 	if (argv[0][1] == ':')

Signature · 1 line

2.21.0

Eiichi Tsukata

author

2019-06-14 07:41 UTC #1 lore raw

PATCH 2/2 tracing/uprobe: Fix obsolete comment on trace_uprobe_create()

Commit 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for uprobe events") cleaned up the usage of trace_uprobe_create(), and the function has been no longer used for removing uprobe/uretprobe.

Signed-off-by Eiichi Tsukata <[email protected]>

---
 kernel/trace/trace_uprobe.c | 2 --
 1 file changed, 2 deletions(-)

kernel/trace/trace_uprobe.c +0 -2

index 7dc8ee55cf84..7860e3f59fad 100644
@@ -426,8 +426,6 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 /*
  * Argument syntax:
  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
- *
- *  - Remove uprobe: -:[GRP/]EVENT
  */
 static int trace_uprobe_create(int argc, const char **argv)
 {

Signature · 1 line

2.21.0

Srikar Dronamraju

Reviewed-by on v1 2/2

2019-06-14 12:32 UTC #2 lore raw

Re: [PATCH 2/2] tracing/uprobe: Fix obsolete comment on trace_uprobe_create()

Quoted 4 lines · Eiichi Tsukata

Commit 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for uprobe events") cleaned up the usage of trace_uprobe_create(), and the function has been no longer used for removing uprobe/uretprobe.

Agree

Reviewed-by Srikar Dronamraju <[email protected]>

Quoted 21 lines

Signed-off-by Eiichi Tsukata <[email protected]>

---
 kernel/trace/trace_uprobe.c | 2 --
 1 file changed, 2 deletions(-)

kernel/trace/trace_uprobe.c +0 -2

index 7dc8ee55cf84..7860e3f59fad 100644
@@ -426,8 +426,6 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 /*
  * Argument syntax:
  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
- *
- *  - Remove uprobe: -:[GRP/]EVENT
  */
 static int trace_uprobe_create(int argc, const char **argv)
 {

Signature · 1 line

2.21.0

Signature · 2 lines

Thanks and Regards
Srikar Dronamraju

Srikar Dronamraju

Reviewed-by on v1 1/2

2019-06-14 12:31 UTC #3 lore raw

In reply to Eiichi Tsukata

Quoted 45 lines · Eiichi Tsukata

Just like the case of commit 8b05a3a7503c ("tracing/kprobes: Fix NULL pointer dereference in trace_kprobe_create()"), writing an incorrectly formatted string to uprobe_events can trigger NULL pointer dereference.
Reporeducer:
  # echo r > /sys/kernel/debug/tracing/uprobe_events
dmesg:
  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 8000000079d12067 P4D 8000000079d12067 PUD 7b7ab067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 PID: 1903 Comm: bash Not tainted 5.2.0-rc3+ #15
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  RIP: 0010:strchr+0x0/0x30
  Code: c0 eb 0d 84 c9 74 18 48 83 c0 01 48 39 d0 74 0f 0f b6 0c 07 3a 0c 06 74 ea 19 c0 83 c8 01 c3 31 c0 c3 0f 1f 84 00 00 00 00 00 <0f> b6 07 89 f2 40 38 f0 75 0e eb 13 0f b6 47 01 48 83 c
  RSP: 0018:ffffb55fc0403d10 EFLAGS: 00010293
RAX: ffff993ffb793400 RBX: 0000000000000000 RCX: ffffffffa4852625
RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000000
RBP: ffffb55fc0403dd0 R08: ffff993ffb793400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff993ff9cc1668 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f30c5147700(0000) GS:ffff993ffda00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007b628000 CR4: 00000000000006f0
  Call Trace:
   trace_uprobe_create+0xe6/0xb10
   ? __kmalloc_track_caller+0xe6/0x1c0
   ? __kmalloc+0xf0/0x1d0
   ? trace_uprobe_create+0xb10/0xb10
   create_or_delete_trace_uprobe+0x35/0x90
   ? trace_uprobe_create+0xb10/0xb10
   trace_run_command+0x9c/0xb0
   trace_parse_run_command+0xf9/0x1eb
   ? probes_open+0x80/0x80
   __vfs_write+0x43/0x90
   vfs_write+0x14a/0x2a0
   ksys_write+0xa2/0x170
   do_syscall_64+0x7f/0x200
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Quoted 6 lines

Fixes 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for uprobe events")
Signed-off-by Eiichi Tsukata <[email protected]>
---
 kernel/trace/trace_uprobe.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Good Catch.

Reviewed-by Srikar Dronamraju <[email protected]>

Signature · 2 lines

Thanks and Regards
Srikar Dronamraju

Masami Hiramatsu

maintainer Acked-by on v1 1/2

2019-06-21 14:22 UTC #4 lore raw

In reply to Eiichi Tsukata

Quoted 45 lines · On Fri, 14 Jun 2019 16:40:25 +0900 Eiichi Tsukata <[email protected]> wrote:

Just like the case of commit 8b05a3a7503c ("tracing/kprobes: Fix NULL pointer dereference in trace_kprobe_create()"), writing an incorrectly formatted string to uprobe_events can trigger NULL pointer dereference.
Reporeducer:
  # echo r > /sys/kernel/debug/tracing/uprobe_events
dmesg:
  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 8000000079d12067 P4D 8000000079d12067 PUD 7b7ab067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 PID: 1903 Comm: bash Not tainted 5.2.0-rc3+ #15
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  RIP: 0010:strchr+0x0/0x30
  Code: c0 eb 0d 84 c9 74 18 48 83 c0 01 48 39 d0 74 0f 0f b6 0c 07 3a 0c 06 74 ea 19 c0 83 c8 01 c3 31 c0 c3 0f 1f 84 00 00 00 00 00 <0f> b6 07 89 f2 40 38 f0 75 0e eb 13 0f b6 47 01 48 83 c
  RSP: 0018:ffffb55fc0403d10 EFLAGS: 00010293
RAX: ffff993ffb793400 RBX: 0000000000000000 RCX: ffffffffa4852625
RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000000
RBP: ffffb55fc0403dd0 R08: ffff993ffb793400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff993ff9cc1668 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f30c5147700(0000) GS:ffff993ffda00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007b628000 CR4: 00000000000006f0
  Call Trace:
   trace_uprobe_create+0xe6/0xb10
   ? __kmalloc_track_caller+0xe6/0x1c0
   ? __kmalloc+0xf0/0x1d0
   ? trace_uprobe_create+0xb10/0xb10
   create_or_delete_trace_uprobe+0x35/0x90
   ? trace_uprobe_create+0xb10/0xb10
   trace_run_command+0x9c/0xb0
   trace_parse_run_command+0xf9/0x1eb
   ? probes_open+0x80/0x80
   __vfs_write+0x43/0x90
   vfs_write+0x14a/0x2a0
   ksys_write+0xa2/0x170
   do_syscall_64+0x7f/0x200
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Quoted 2 lines

Fixes 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for uprobe events")
Signed-off-by Eiichi Tsukata <[email protected]>

Sorry, I missed this fix.

Acked-by Masami Hiramatsu <[email protected]>

Steve, could you pick this as an urgent fix?

Thank you!

Quoted 32 lines

---
 kernel/trace/trace_uprobe.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

kernel/trace/trace_uprobe.c +10 -3

index 0d60d6856de5..7dc8ee55cf84 100644
@@ -443,10 +443,17 @@ static int trace_uprobe_create(int argc, const char **argv)
 	ret = 0;
 	ref_ctr_offset = 0;
 
-	/* argc must be >= 1 */
-	if (argv[0][0] == 'r')
+	switch (argv[0][0]) {
+	case 'r':
 		is_return = true;
-	else if (argv[0][0] != 'p' || argc < 2)
+		break;
+	case 'p':
+		break;
+	default:
+		return -ECANCELED;
+	}
+
+	if (argc < 2)
 		return -ECANCELED;
 
 	if (argv[0][1] == ':')

Signature · 1 line

2.21.0

Signature · 1 line

Masami Hiramatsu <[email protected]>