kernel/git/stable/linux.git/fs/proc/self.c, branch linux-4.4.y

proc: don't allow async path resolution of /proc/self components

2020-12-02T07:29:27+00:00

[ Upstream commit 8d4c3e76e3be11a64df95ddee52e99092d42fc19 ] If this is attempted by a kthread, then return -EOPNOTSUPP as we don't currently support that. Once we can get task_pid_ptr() doing the right thing, then this can go away again. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

proc: Use new_inode not new_inode_pseudo

2020-06-20T08:23:18+00:00

commit ef1548adada51a2f32ed7faef50aa465e1b4c5da upstream. Recently syzbot reported that unmounting proc when there is an ongoing inotify watch on the root directory of proc could result in a use after free when the watch is removed after the unmount of proc when the watcher exits. Commit 69879c01a0c3 ("proc: Remove the now unnecessary internal mount of proc") made it easier to unmount proc and allowed syzbot to see the problem, but looking at the code it has been around for a long time. Looking at the code the fsnotify watch should have been removed by fsnotify_sb_delete in generic_shutdown_super. Unfortunately the inode was allocated with new_inode_pseudo instead of new_inode so the inode was not on the sb->s_inodes list. Which prevented fsnotify_unmount_inodes from finding the inode and removing the watch as well as made it so the "VFS: Busy inodes after unmount" warning could not find the inodes to warn about them. Make all of the inodes in proc visible to generic_shutdown_super, and fsnotify_sb_delete by using new_inode instead of new_inode_pseudo. The only functional difference is that new_inode places the inodes on the sb->s_inodes list. I wrote a small test program and I can verify that without changes it can trigger this issue, and by replacing new_inode_pseudo with new_inode the issues goes away. Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/000000000000d788c905a7dfa3f4@google.com Reported-by: syzbot+7d2debdcdb3cb93c1e5e@syzkaller.appspotmail.com Fixes: 0097875bd415 ("proc: Implement /proc/thread-self to point at the directory of the current thread") Fixes: 021ada7dff22 ("procfs: switch /proc/self away from proc_dir_entry") Fixes: 51f0885e5415 ("vfs,proc: guarantee unique inodes in /proc") Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

don't pass nameidata to ->follow_link()

2015-05-11T02:20:15+00:00

its only use is getting passed to nd_jump_link(), which can obtain it from current->nameidata Signed-off-by: Al Viro

new ->follow_link() and ->put_link() calling conventions

2015-05-11T02:19:45+00:00

a) instead of storing the symlink body (via nd_set_link()) and returning an opaque pointer later passed to ->put_link(), ->follow_link() _stores_ that opaque pointer (into void * passed by address by caller) and returns the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic symlinks) and pointer to symlink body for normal symlinks. Stored pointer is ignored in all cases except the last one. Storing NULL for opaque pointer (or not storing it at all) means no call of ->put_link(). b) the body used to be passed to ->put_link() implicitly (via nameidata). Now only the opaque pointer is. In the cases when we used the symlink body to free stuff, ->follow_link() now should store it as opaque pointer in addition to returning it. Signed-off-by: Al Viro

VFS: normal filesystems (and lustre): d_inode() annotations

2015-04-15T19:06:57+00:00

that's the bulk of filesystem drivers dealing with inodes of their own Signed-off-by: David Howells Signed-off-by: Al Viro

new helper: readlink_copy()

2014-04-02T03:19:15+00:00

Signed-off-by: Al Viro

new helper: kfree_put_link()

2013-10-25T03:34:49+00:00

duplicated to hell and back... Signed-off-by: Al Viro

Include missing linux/slab.h inclusions

2013-04-29T19:42:01+00:00

Include missing linux/slab.h inclusions where the source file is currently expecting to get kmalloc() and co. through linux/proc_fs.h. Signed-off-by: David Howells Acked-by: Greg Kroah-Hartman cc: linux-s390@vger.kernel.org cc: sparclinux@vger.kernel.org cc: linux-efi@vger.kernel.org cc: linux-mtd@lists.infradead.org cc: devel@driverdev.osuosl.org cc: x86@kernel.org Signed-off-by: Al Viro

procfs: switch /proc/self away from proc_dir_entry

2013-04-09T18:13:05+00:00

Just have it pinned in dcache all along and let procfs ->kill_sb() drop it before kill_anon_super(). Signed-off-by: Al Viro

mode_t, whack-a-mole at 11...

2013-04-09T18:13:05+00:00

Signed-off-by: Al Viro