linux/fs/ecryptfs, branch v3.2.52

eCryptfs: check for eCryptfs cipher support at mount

2012-11-16T16:47:19Z

commit 5f5b331d5c21228a6519dcb793fc1629646c51a6 upstream. The issue occurs when eCryptfs is mounted with a cipher supported by the crypto subsystem but not by eCryptfs. The mount succeeds and an error does not occur until a write. This change checks for eCryptfs cipher support at mount time. Resolves Launchpad issue #338914, reported by Tyler Hicks in 03/2009. https://bugs.launchpad.net/ecryptfs/+bug/338914 Signed-off-by: Tim Sally Signed-off-by: Tyler Hicks Signed-off-by: Ben Hutchings

eCryptfs: Copy up POSIX ACL and read-only flags from lower mount

2012-11-16T16:47:18Z

commit 069ddcda37b2cf5bb4b6031a944c0e9359213262 upstream. When the eCryptfs mount options do not include '-o acl', but the lower filesystem's mount options do include 'acl', the MS_POSIXACL flag is not flipped on in the eCryptfs super block flags. This flag is what the VFS checks in do_last() when deciding if the current umask should be applied to a newly created inode's mode or not. When a default POSIX ACL mask is set on a directory, the current umask is incorrectly applied to new inodes created in the directory. This patch ignores the MS_POSIXACL flag passed into ecryptfs_mount() and sets the flag on the eCryptfs super block depending on the flag's presence on the lower super block. Additionally, it is incorrect to allow a writeable eCryptfs mount on top of a read-only lower mount. This missing check did not allow writes to the read-only lower mount because permissions checks are still performed on the lower filesystem's objects but it is best to simply not allow a rw mount on top of ro mount. However, a ro eCryptfs mount on top of a rw mount is valid and still allowed. https://launchpad.net/bugs/1009207 Signed-off-by: Tyler Hicks Reported-by: Stefan Beller Cc: John Johansen Signed-off-by: Ben Hutchings

eCryptfs: Call lower ->flush() from ecryptfs_flush()

2012-10-17T02:49:54Z

commit 64e6651dcc10e9d2cc6230208a8e6c2cfd19ae18 upstream. Since eCryptfs only calls fput() on the lower file in ecryptfs_release(), eCryptfs should call the lower filesystem's ->flush() from ecryptfs_flush(). If the lower filesystem implements ->flush(), then eCryptfs should try to flush out any dirty pages prior to calling the lower ->flush(). If the lower filesystem does not implement ->flush(), then eCryptfs has no need to do anything in ecryptfs_flush() since dirty pages are now written out to the lower filesystem in ecryptfs_release(). Signed-off-by: Tyler Hicks Signed-off-by: Ben Hutchings

eCryptfs: Write out all dirty pages just before releasing the lower file

2012-10-17T02:49:53Z

commit 7149f2558d5b5b988726662fe58b1c388337805b upstream. Fixes a regression caused by: 821f749 eCryptfs: Revert to a writethrough cache model That patch reverted some code (specifically, 32001d6f) that was necessary to properly handle open() -> mmap() -> close() -> dirty pages -> munmap(), because the lower file could be closed before the dirty pages are written out. Rather than reapplying 32001d6f, this approach is a better way of ensuring that the lower file is still open in order to handle writing out the dirty pages. It is called from ecryptfs_release(), while we have a lock on the lower file pointer, just before the lower file gets the final fput() and we overwrite the pointer. https://launchpad.net/bugs/1047261 Signed-off-by: Tyler Hicks Reported-by: Artemy Tregubenko Tested-by: Artemy Tregubenko Tested-by: Colin Ian King Signed-off-by: Ben Hutchings

eCryptfs: Revert to a writethrough cache model

2012-10-17T02:49:52Z

commit 821f7494a77627fb1ab539591c57b22cdca702d6 upstream. A change was made about a year ago to get eCryptfs to better utilize its page cache during writes. The idea was to do the page encryption operations during page writeback, rather than doing them when initially writing into the page cache, to reduce the number of page encryption operations during sequential writes. This meant that the encrypted page would only be written to the lower filesystem during page writeback, which was a change from how eCryptfs had previously wrote to the lower filesystem in ecryptfs_write_end(). The change caused a few eCryptfs-internal bugs that were shook out. Unfortunately, more grave side effects have been identified that will force changes outside of eCryptfs. Because the lower filesystem isn't consulted until page writeback, eCryptfs has no way to pass lower write errors (ENOSPC, mainly) back to userspace. Additionaly, it was reported that quotas could be bypassed because of the way eCryptfs may sometimes open the lower filesystem using a privileged kthread. It would be nice to resolve the latest issues, but it is best if the eCryptfs commits be reverted to the old behavior in the meantime. This reverts: 32001d6f "eCryptfs: Flush file in vma close" 5be79de2 "eCryptfs: Flush dirty pages in setattr" 57db4e8d "ecryptfs: modify write path to encrypt page in writepage" Signed-off-by: Tyler Hicks Tested-by: Colin King Cc: Colin King Cc: Thieu Le Signed-off-by: Ben Hutchings

eCryptfs: Initialize empty lower files when opening them

2012-10-17T02:49:52Z

commit e3ccaa9761200952cc269b1f4b7d7bb77a5e071b upstream. Historically, eCryptfs has only initialized lower files in the ecryptfs_create() path. Lower file initialization is the act of writing the cryptographic metadata from the inode's crypt_stat to the header of the file. The ecryptfs_open() path already expects that metadata to be in the header of the file. A number of users have reported empty lower files in beneath their eCryptfs mounts. Most of the causes for those empty files being left around have been addressed, but the presence of empty files causes problems due to the lack of proper cryptographic metadata. To transparently solve this problem, this patch initializes empty lower files in the ecryptfs_open() error path. If the metadata is unreadable due to the lower inode size being 0, plaintext passthrough support is not in use, and the metadata is stored in the header of the file (as opposed to the user.ecryptfs extended attribute), the lower file will be initialized. The number of nested conditionals in ecryptfs_open() was getting out of hand, so a helper function was created. To avoid the same nested conditional problem, the conditional logic was reversed inside of the helper function. https://launchpad.net/bugs/911507 Signed-off-by: Tyler Hicks Cc: John Johansen Cc: Colin Ian King Signed-off-by: Ben Hutchings

eCryptfs: Unlink lower inode when ecryptfs_create() fails

2012-10-17T02:49:51Z

commit 8bc2d3cf612994a960c2e8eaea37f6676f67082a upstream. ecryptfs_create() creates a lower inode, allocates an eCryptfs inode, initializes the eCryptfs inode and cryptographic metadata attached to the inode, and then writes the metadata to the header of the file. If an error was to occur after the lower inode was created, an empty lower file would be left in the lower filesystem. This is a problem because ecryptfs_open() refuses to open any lower files which do not have the appropriate metadata in the file header. This patch properly unlinks the lower inode when an error occurs in the later stages of ecryptfs_create(), reducing the chance that an empty lower file will be left in the lower filesystem. https://launchpad.net/bugs/872905 Signed-off-by: Tyler Hicks Cc: John Johansen Cc: Colin Ian King Signed-off-by: Ben Hutchings

eCryptfs: Copy up attributes of the lower target inode after rename

2012-09-19T14:05:24Z

commit 8335eafc2859e1a26282bef7c3d19f3d68868b8a upstream. After calling into the lower filesystem to do a rename, the lower target inode's attributes were not copied up to the eCryptfs target inode. This resulted in the eCryptfs target inode staying around, rather than being evicted, because i_nlink was not updated for the eCryptfs inode. This also meant that eCryptfs didn't do the final iput() on the lower target inode so it stayed around, as well. This would result in a failure to free up space occupied by the target file in the rename() operation. Both target inodes would eventually be evicted when the eCryptfs filesystem was unmounted. This patch calls fsstack_copy_attr_all() after the lower filesystem does its ->rename() so that important inode attributes, such as i_nlink, are updated at the eCryptfs layer. ecryptfs_evict_inode() is now called and eCryptfs can drop its final reference on the lower inode. http://launchpad.net/bugs/561129 Signed-off-by: Tyler Hicks Tested-by: Colin Ian King Signed-off-by: Ben Hutchings

eCryptfs: Properly check for O_RDONLY flag before doing privileged open

2012-07-25T03:11:44Z

commit 9fe79d7600497ed8a95c3981cbe5b73ab98222f0 upstream. If the first attempt at opening the lower file read/write fails, eCryptfs will retry using a privileged kthread. However, the privileged retry should not happen if the lower file's inode is read-only because a read/write open will still be unsuccessful. The check for determining if the open should be retried was intended to be based on the access mode of the lower file's open flags being O_RDONLY, but the check was incorrectly performed. This would cause the open to be retried by the privileged kthread, resulting in a second failed open of the lower file. This patch corrects the check to determine if the open request should be handled by the privileged kthread. Signed-off-by: Tyler Hicks Reported-by: Dan Carpenter Acked-by: Dan Carpenter Signed-off-by: Ben Hutchings

eCryptfs: Fix lockdep warning in miscdev operations

2012-07-25T03:11:44Z

commit 60d65f1f07a7d81d3eb3b91fc13fca80f2fdbb12 upstream. Don't grab the daemon mutex while holding the message context mutex. Addresses this lockdep warning: ecryptfsd/2141 is trying to acquire lock: (&ecryptfs_msg_ctx_arr[i].mux){+.+.+.}, at: [] ecryptfs_miscdev_read+0x143/0x470 [ecryptfs] but task is already holding lock: (&(*daemon)->mux){+.+...}, at: [] ecryptfs_miscdev_read+0x21c/0x470 [ecryptfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&(*daemon)->mux){+.+...}: [] lock_acquire+0x9d/0x220 [] __mutex_lock_common+0x5a/0x4b0 [] mutex_lock_nested+0x44/0x50 [] ecryptfs_send_miscdev+0x97/0x120 [ecryptfs] [] ecryptfs_send_message+0x134/0x1e0 [ecryptfs] [] ecryptfs_generate_key_packet_set+0x2fe/0xa80 [ecryptfs] [] ecryptfs_write_metadata+0x108/0x250 [ecryptfs] [] ecryptfs_create+0x130/0x250 [ecryptfs] [] vfs_create+0xb4/0x120 [] do_last+0x8c5/0xa10 [] path_openat+0xd9/0x460 [] do_filp_open+0x42/0xa0 [] do_sys_open+0xf8/0x1d0 [] sys_open+0x21/0x30 [] system_call_fastpath+0x16/0x1b -> #0 (&ecryptfs_msg_ctx_arr[i].mux){+.+.+.}: [] __lock_acquire+0x1bf8/0x1c50 [] lock_acquire+0x9d/0x220 [] __mutex_lock_common+0x5a/0x4b0 [] mutex_lock_nested+0x44/0x50 [] ecryptfs_miscdev_read+0x143/0x470 [ecryptfs] [] vfs_read+0xb3/0x180 [] sys_read+0x4d/0x90 [] system_call_fastpath+0x16/0x1b Signed-off-by: Tyler Hicks Signed-off-by: Ben Hutchings