Il 25/08/2013 17:04, Alexander Graf ha scritto: > > On 24.08.2013, at 21:14, Yann Droneaud wrote: > >> KVM uses anon_inode_get() to allocate file descriptors as part >> of some of its ioctls. But those ioctls are lacking a flag argument >> allowing userspace to choose options for the newly opened file descriptor. >> >> In such case it's advised to use O_CLOEXEC by default so that >> userspace is allowed to choose, without race, if the file descriptor >> is going to be inherited across exec(). >> >> This patch set O_CLOEXEC flag on all file descriptors created >> with anon_inode_getfd() to not leak file descriptors across exec(). >> >> Signed-off-by: Yann Droneaud <ydroneaud@xxxxxxxxxx> >> Link: http://lkml.kernel.org/r/cover.1377372576.git.ydroneaud@xxxxxxxxxx > > Reviewed-by: Alexander Graf <agraf@xxxxxxx> > > Would it make sense to simply inherit the O_CLOEXEC flag from the > parent kvm fd instead? That would give user space the power to keep > fds across exec() if it wants to. Does it make sense to use non-O_CLOEXEC file descriptors with KVM at all? Besides fork() not being supported by KVM, as described in Documentation/virtual/kvm/api.txt, the VMAs of the parent process go away as soon as you exec(). I'm not sure how you can use the inherited file descriptor in a sensible way after exec(). Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
