Eric Lee / smarc-ti-linux-kernel

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Commit 7612bfeecc197bbb6629842b5c6ff1967f0a9b70

Authored by Kees Cook
Committed by James Morris
1 parent d9875690d9
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

Yama: access task_struct->comm directly 

The core ptrace access checking routine holds a task lock, and when
reporting a failure, Yama takes a separate task lock. To avoid a
potential deadlock with two ptracers taking the opposite locks, do not
use get_task_comm() and just use ->comm directly since accuracy is not
important for the report.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
CC: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

Showing 1 changed file with 2 additions and 8 deletions Side-by-side Diff

security/yama/yama_lsm.c
Diff comments   View file @ 7612bfe
... ... @@ -279,12 +279,9 @@
279 279 }
280 280  
281 281 if (rc) {
282   - char name[sizeof(current->comm)];
283 282 printk_ratelimited(KERN_NOTICE
284 283 "ptrace of pid %d was attempted by: %s (pid %d)\n",
285   - child->pid,
286   - get_task_comm(name, current),
287   - current->pid);
  284 + child->pid, current->comm, current->pid);
288 285 }
289 286  
290 287 return rc;
291 288  
... ... @@ -319,12 +316,9 @@
319 316 }
320 317  
321 318 if (rc) {
322   - char name[sizeof(current->comm)];
323 319 printk_ratelimited(KERN_NOTICE
324 320 "ptraceme of pid %d was attempted by: %s (pid %d)\n",
325   - current->pid,
326   - get_task_comm(name, parent),
327   - parent->pid);
  321 + current->pid, parent->comm, parent->pid);
328 322 }
329 323  
330 324 return rc;