On Sun, 2024-02-04 at 02:14 +0000, Al Viro wrote:
> We still have some races in filesystem methods when exposed
> to RCU pathwalk. The series below is a result of code audit (the
> second round of it) and it should deal with most of that stuff.
> Exceptions: ntfs3 ->d_hash()/->d_compare() and ceph_d_revalidate().
> Up to maintainers (a note for NTFS folks - when documentation says
> that a method may not block, it *does* imply that blocking allocations
> are to be avoided. Really).
>
> Branch is 6.8-rc1-based; it lives in
> git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git fixes.pathwalk-rcu
>
> Individual patches are in followups; ditto for code audit notes. Beginning
> of the latter should probably be converted into docs; if anyone is willing
> to help with such conversion, please say so - I'll be glad to answer any
> questions, etc.
>
> If somebody wants to grab bits and pieces of that series into individual
> filesystem git trees, please say so. Same for any problems spotted in
> the patches, obviously. If nothing shows up, that goes into #fixes and
> into mainline.
>
> Shortlog:
> fs/super.c: don't drop ->s_user_ns until we free struct super_block itself
> rcu pathwalk: prevent bogus hard errors from may_lookup()
> affs: free affs_sb_info with kfree_rcu()
> exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper
> hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_info
> afs: fix __afs_break_callback() / afs_drop_open_mmap() race
> nfs: make nfs_set_verifier() safe for use in RCU pathwalk
> nfs: fix UAF on pathwalk running into umount
> procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()
> procfs: make freeing proc_fs_info rcu-delayed
> fuse: fix UAF in rcu pathwalks
> cifs_get_link(): bail out in unsafe case
> ext4_get_link(): fix breakage in RCU mode
>
> Diffstat:
> fs/affs/affs.h | 1 +
> fs/affs/super.c | 2 +-
> fs/afs/file.c | 8 ++++++--
> fs/exfat/exfat_fs.h | 1 +
> fs/exfat/nls.c | 14 ++++----------
> fs/exfat/super.c | 20 +++++++++++---------
> fs/ext4/symlink.c | 8 +++++---
> fs/fuse/cuse.c | 3 +--
> fs/fuse/fuse_i.h | 1 +
> fs/fuse/inode.c | 15 +++++++++++----
> fs/hfsplus/hfsplus_fs.h | 1 +
> fs/hfsplus/super.c | 12 +++++++++---
> fs/namei.c | 6 +++++-
> fs/nfs/client.c | 13 ++++++++++---
> fs/nfs/dir.c | 4 ++--
> fs/proc/base.c | 2 --
> fs/proc/inode.c | 19 ++++++++-----------
> fs/proc/root.c | 2 +-
> fs/smb/client/cifsfs.c | 3 +++
> fs/super.c | 13 ++++---------
> include/linux/nfs_fs_sb.h | 2 ++
> include/linux/proc_fs.h | 1 +
> 22 files changed, 88 insertions(+), 63 deletions(-)
>
Reviewed-by: Jeff Layton <[email protected]>