Christian Brauner <christian@xxxxxxxxxx> wrote: > This makes all file descriptors returned from new syscalls of the new mount > api cloexec by default. > > From a userspace perspective it is rarely the case that fds are supposed to > be inherited across exec. Having them not cloexec by default forces > userspace to remember to pass the <SPECIFIC>_CLOEXEC flag along or to > invoke fcntl() on the fd to prevent leaking it. And leaking the fd is a > much bigger issue than forgetting to remove the cloexec flag and failing to > inherit the fd. > For old fd types we can't break userspace. But for new ones we should > whenever reasonable make them cloexec by default (Examples of this policy > are the new seccomp notify fds and also pidfds.). If userspace wants to > inherit fds across exec they can remove the O_CLOEXEC flag and so opt in to > inheritance explicitly. > > This patch also has the advantage that we can get rid of all the special > flags per file descriptor type for the new mount api. In total this lets us > remove 4 flags: > - FSMOUNT_CLOEXEC > - FSOPEN_CLOEXEC > - FSPICK_CLOEXEC > - OPEN_TREE_CLOEXEC > > Signed-off-by: Christian Brauner <christian@xxxxxxxxxx> Fine by me. Reviewed-by: David Howells <dhowells@xxxxxxxxxx>
