[PATCH v6 14/16] pidfd: Use new infrastructure to fix deadlocks in execve
From: Bernd Edlinger <hidden>
Date: 2020-03-21 02:46:25
Also in:
linux-api, linux-doc, linux-fsdevel, lkml, stable
Subsystem:
the rest · Maintainer:
Linus Torvalds
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 <redacted> --- kernel/pid.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/pid.c b/kernel/pid.c
index 0f4ecb5..04821f4 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c@@ -584,7 +584,7 @@ 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);
@@ -593,7 +593,7 @@ 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); }
--
1.9.1