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authorBernd Edlinger <bernd.edlinger@hotmail.de>2020-03-21 02:46:16 +0000
committerEric W. Biederman <ebiederm@xmission.com>2020-03-25 10:04:01 -0500
commit501f9328bf5c6b5e4863da4b50e0e86792de3aa9 (patch)
tree1daa6f09d76a01c93cb59372e85e017a833ca5c9
parent6914303824bb572278568330d72fc1f8f9814e67 (diff)
pidfd: Use new infrastructure to fix deadlocks in execve
This changes __pidfd_fget to use the new exec_update_mutex instead of cred_guard_mutex. This should be safe, as the credentials do not change before exec_update_mutex is locked. Therefore whatever file access is possible with holding the cred_guard_mutex here is also possbile with the exec_update_mutex. Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
-rw-r--r--kernel/pid.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/pid.c b/kernel/pid.c
index 60820e72634c..efd34874b3d1 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -577,7 +577,7 @@ static struct file *__pidfd_fget(struct task_struct *task, int fd)
struct file *file;
int ret;
- ret = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ ret = mutex_lock_killable(&task->signal->exec_update_mutex);
if (ret)
return ERR_PTR(ret);
@@ -586,7 +586,7 @@ static struct file *__pidfd_fget(struct task_struct *task, int fd)
else
file = ERR_PTR(-EPERM);
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
return file ?: ERR_PTR(-EBADF);
}