Commit 7612bfee authored by Kees Cook's avatar Kees Cook Committed by James Morris

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: default avatarFengguang Wu <fengguang.wu@intel.com>
Suggested-by: default avatarOleg Nesterov <oleg@redhat.com>
CC: stable@vger.kernel.org
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarJohn Johansen <john.johansen@canonical.com>
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent d9875690
...@@ -279,12 +279,9 @@ static int yama_ptrace_access_check(struct task_struct *child, ...@@ -279,12 +279,9 @@ static int yama_ptrace_access_check(struct task_struct *child,
} }
if (rc) { if (rc) {
char name[sizeof(current->comm)];
printk_ratelimited(KERN_NOTICE printk_ratelimited(KERN_NOTICE
"ptrace of pid %d was attempted by: %s (pid %d)\n", "ptrace of pid %d was attempted by: %s (pid %d)\n",
child->pid, child->pid, current->comm, current->pid);
get_task_comm(name, current),
current->pid);
} }
return rc; return rc;
...@@ -319,12 +316,9 @@ static int yama_ptrace_traceme(struct task_struct *parent) ...@@ -319,12 +316,9 @@ static int yama_ptrace_traceme(struct task_struct *parent)
} }
if (rc) { if (rc) {
char name[sizeof(current->comm)];
printk_ratelimited(KERN_NOTICE printk_ratelimited(KERN_NOTICE
"ptraceme of pid %d was attempted by: %s (pid %d)\n", "ptraceme of pid %d was attempted by: %s (pid %d)\n",
current->pid, current->pid, parent->comm, parent->pid);
get_task_comm(name, parent),
parent->pid);
} }
return rc; return rc;
......
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