user/sven/linux.git/fs/super.c, branch v6.3.3

fscrypt: destroy keyring after security_sb_delete()

2023-03-14T17:30:30Z

fscrypt_destroy_keyring() must be called after all potentially-encrypted inodes were evicted; otherwise it cannot safely destroy the keyring. Since inodes that are in-use by the Landlock LSM don't get evicted until security_sb_delete(), this means that fscrypt_destroy_keyring() must be called *after* security_sb_delete(). This fixes a WARN_ON followed by a NULL dereference, only possible if Landlock was being used on encrypted files. Fixes: d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key") Cc: stable@vger.kernel.org Reported-by: syzbot+93e495f6a4f748827c88@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/00000000000044651705f6ca1e30@google.com Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20230313221231.272498-2-ebiggers@kernel.org Signed-off-by: Eric Biggers

Merge tag 'for-6.3/dio-2023-02-16' of git://git.kernel.dk/linux

2023-02-20T22:10:36Z

Pull legacy dio update from Jens Axboe: "We only have a few file systems that use the old dio code, make them select it rather than build it unconditionally" * tag 'for-6.3/dio-2023-02-16' of git://git.kernel.dk/linux: fs: build the legacy direct I/O code conditionally fs: move sb_init_dio_done_wq out of direct-io.c

Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux

2023-02-20T20:29:27Z

Pull fscrypt updates from Eric Biggers: "Simplify the implementation of the test_dummy_encryption mount option by adding the 'test dummy key' on-demand" * tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux: fscrypt: clean up fscrypt_add_test_dummy_key() fs/super.c: stop calling fscrypt_destroy_keyring() from __put_super() f2fs: stop calling fscrypt_add_test_dummy_key() ext4: stop calling fscrypt_add_test_dummy_key() fscrypt: add the test dummy encryption key on-demand

fs/super.c: stop calling fscrypt_destroy_keyring() from __put_super()

2023-02-08T06:30:30Z

Now that the key associated with the "test_dummy_operation" mount option is added on-demand when it's needed, rather than immediately when the filesystem is mounted, fscrypt_destroy_keyring() no longer needs to be called from __put_super() to avoid a memory leak on mount failure. Remove this call, which was causing confusion because it appeared to be a sleep-in-atomic bug (though it wasn't, for a somewhat-subtle reason). Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20230208062107.199831-5-ebiggers@kernel.org

fs: Use CHECK_DATA_CORRUPTION() when kernel bugs are detected

2023-01-27T13:17:22Z

Currently, filp_close() and generic_shutdown_super() use printk() to log messages when bugs are detected. This is problematic because infrastructure like syzkaller has no idea that this message indicates a bug. In addition, some people explicitly want their kernels to BUG() when kernel data corruption has been detected (CONFIG_BUG_ON_DATA_CORRUPTION). And finally, when generic_shutdown_super() detects remaining inodes on a system without CONFIG_BUG_ON_DATA_CORRUPTION, it would be nice if later accesses to a busy inode would at least crash somewhat cleanly rather than walking through freed memory. To address all three, use CHECK_DATA_CORRUPTION() when kernel bugs are detected. Signed-off-by: Jann Horn Reviewed-by: Christian Brauner (Microsoft) Reviewed-by: Kees Cook Signed-off-by: Christian Brauner (Microsoft)

fs: move sb_init_dio_done_wq out of direct-io.c

2023-01-26T17:30:56Z

sb_init_dio_done_wq is also used by the iomap code, so move it to super.c in preparation for building direct-io.c conditionally. Signed-off-by: Christoph Hellwig Reviewed-by: Eric Biggers Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230125065839.191256-2-hch@lst.de Signed-off-by: Jens Axboe

Merge tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2022-12-13T02:38:47Z

Pull misc vfs updates from Al Viro: "misc pile" * tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: sysv: Fix sysv_nblocks() returns wrong value get rid of INT_LIMIT, use type_max() instead btrfs: replace INT_LIMIT(loff_t) with OFFSET_MAX fs: simplify vfs_get_super fs: drop useless condition from inode_needs_update_time

fs: simplify vfs_get_super

2022-11-25T05:52:19Z

Remove the pointless keying argument and associated enum and pass the fill_super callback and a "bool reconf" instead. Also mark the function static given that there are no users outside of super.c. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

fscrypt: fix keyring memory leak on mount failure

2022-10-20T03:54:43Z

Commit d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key") moved the keyring destruction from __put_super() to generic_shutdown_super() so that the filesystem's block device(s) are still available. Unfortunately, this causes a memory leak in the case where a mount is attempted with the test_dummy_encryption mount option, but the mount fails after the option has already been processed. To fix this, attempt the keyring destruction in both places. Reported-by: syzbot+104c2a89561289cec13e@syzkaller.appspotmail.com Fixes: d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key") Signed-off-by: Eric Biggers Reviewed-by: Christian Brauner (Microsoft) Link: https://lore.kernel.org/r/20221011213838.209879-1-ebiggers@kernel.org

fscrypt: stop using keyrings subsystem for fscrypt_master_key

2022-09-22T03:33:06Z

The approach of fs/crypto/ internally managing the fscrypt_master_key structs as the payloads of "struct key" objects contained in a "struct key" keyring has outlived its usefulness. The original idea was to simplify the code by reusing code from the keyrings subsystem. However, several issues have arisen that can't easily be resolved: - When a master key struct is destroyed, blk_crypto_evict_key() must be called on any per-mode keys embedded in it. (This started being the case when inline encryption support was added.) Yet, the keyrings subsystem can arbitrarily delay the destruction of keys, even past the time the filesystem was unmounted. Therefore, currently there is no easy way to call blk_crypto_evict_key() when a master key is destroyed. Currently, this is worked around by holding an extra reference to the filesystem's request_queue(s). But it was overlooked that the request_queue reference is *not* guaranteed to pin the corresponding blk_crypto_profile too; for device-mapper devices that support inline crypto, it doesn't. This can cause a use-after-free. - When the last inode that was using an incompletely-removed master key is evicted, the master key removal is completed by removing the key struct from the keyring. Currently this is done via key_invalidate(). Yet, key_invalidate() takes the key semaphore. This can deadlock when called from the shrinker, since in fscrypt_ioctl_add_key(), memory is allocated with GFP_KERNEL under the same semaphore. - More generally, the fact that the keyrings subsystem can arbitrarily delay the destruction of keys (via garbage collection delay, or via random processes getting temporary key references) is undesirable, as it means we can't strictly guarantee that all secrets are ever wiped. - Doing the master key lookups via the keyrings subsystem results in the key_permission LSM hook being called. fscrypt doesn't want this, as all access control for encrypted files is designed to happen via the files themselves, like any other files. The workaround which SELinux users are using is to change their SELinux policy to grant key search access to all domains. This works, but it is an odd extra step that shouldn't really have to be done. The fix for all these issues is to change the implementation to what I should have done originally: don't use the keyrings subsystem to keep track of the filesystem's fscrypt_master_key structs. Instead, just store them in a regular kernel data structure, and rework the reference counting, locking, and lifetime accordingly. Retain support for RCU-mode key lookups by using a hash table. Replace fscrypt_sb_free() with fscrypt_sb_delete(), which releases the keys synchronously and runs a bit earlier during unmount, so that block devices are still available. A side effect of this patch is that neither the master keys themselves nor the filesystem keyrings will be listed in /proc/keys anymore. ("Master key users" and the master key users keyrings will still be listed.) However, this was mostly an implementation detail, and it was intended just for debugging purposes. I don't know of anyone using it. This patch does *not* change how "master key users" (->mk_users) works; that still uses the keyrings subsystem. That is still needed for key quotas, and changing that isn't necessary to solve the issues listed above. If we decide to change that too, it would be a separate patch. I've marked this as fixing the original commit that added the fscrypt keyring, but as noted above the most important issue that this patch fixes wasn't introduced until the addition of inline encryption support. Fixes: 22d94f493bfb ("fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl") Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20220901193208.138056-2-ebiggers@kernel.org