@@ -606,7 +606,7 @@ static int pidfd_getfd(struct pid *pid, int fd)
{
struct task_struct *task;
struct file *file;
- int ret;
+ int ret, err;
task = get_pid_task(pid, PIDTYPE_PID);
if (!task)
@@ -617,18 +617,16 @@ static int pidfd_getfd(struct pid *pid, int fd)
if (IS_ERR(file))
return PTR_ERR(file);
- ret = security_file_receive(file);
- if (ret) {
- fput(file);
- return ret;
- }
-
ret = get_unused_fd_flags(O_CLOEXEC);
- if (ret < 0)
- fput(file);
- else
- fd_install(ret, file);
+ if (ret >= 0) {
+ err = file_receive(ret, file);
+ if (err) {
+ put_unused_fd(ret);
+ ret = err;
+ }
+ }
+ fput(file);
return ret;
}
The code to copy file descriptors was duplicated in pidfd_getfd. Rather than continue to duplicate it, this hoists the code out of kernel/pid.c and uses the newly added file_receive helper. Earlier, when this was implemented there was some back-and-forth about how the semantics should work around copying around file descriptors [1], and it was decided that the default behaviour should be to not modify cgroup data. As a matter of least surprise, this approach follows the default semantics as presented by SCM_RIGHTS. In the future, a flag can be added to avoid manipulating the cgroup data on copy. [1]: https://lore.kernel.org/lkml/20200107175927.4558-1-sargun@sargun.me/ Signed-off-by: Sargun Dhillon <sargun@sargun.me> Suggested-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Daniel Wagner <daniel.wagner@bmw-carit.de> Cc: David S. Miller <davem@davemloft.net> Cc: Jann Horn <jannh@google.com> Cc: John Fastabend <john.r.fastabend@intel.com> Cc: Tejun Heo <tj@kernel.org> Cc: Tycho Andersen <tycho@tycho.ws> Cc: stable@vger.kernel.org Cc: cgroups@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- kernel/pid.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-)