tracing/uprobe: Fix NULL pointer dereference in trace_uprobe_create()
Just like the case of commit
867fc584a0b0 ("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
Link: http://lkml.kernel.org/r/20190614074026.8045-1-devel@etsukata.com
Cc: stable@vger.kernel.org
Fixes: 6b638f0c2c78 ("tracing/uprobes: Use dyn_event framework for uprobe events")
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>