Returns an error when an unrecognized cipher code is present in a tag 3
packet or an ecryptfs_crypt_stat cannot be initialized. Also sets an
crypt_stat->tfm error pointer to NULL to ensure that it will not be
incorrectly freed in ecryptfs_destroy_crypt_stat().
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Cc: stable <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
So, I compiled a 2.6.31-rc5 kernel with ecryptfs and loaded its module.
When it came time to mount my filesystem, I got this in dmesg, and it
refused to mount:
[93577.776637] Unable to allocate crypto cipher with name [aes]; rc = [-2]
[93577.783280] Error attempting to initialize key TFM cipher with name = [aes]; rc = [-2]
[93577.791183] Error attempting to initialize cipher with name = [aes] and key size = [32]; rc = [-2]
[93577.800113] Error parsing options; rc = [-22]
I figured from the error message that I'd either forgotten to load "aes"
or that my key size was bogus. Neither one of those was the case. In
fact, I was missing the CRYPTO_ECB config option and the 'ecb' module.
Unfortunately, there's no trace of 'ecb' in that error message.
I've done two things to fix this. First, I've modified ecryptfs's
Kconfig entry to select CRYPTO_ECB and CRYPTO_CBC. I also took CRYPTO
out of the dependencies since the 'select' will take care of it for us.
I've also modified the error messages to print a string that should
contain both 'ecb' and 'aes' in my error case. That will give any
future users a chance of finding the right modules and Kconfig options.
I also wonder if we should:
select CRYPTO_AES if !EMBEDDED
since I think most ecryptfs users are using AES like me.
Cc: ecryptfs-devel@lists.launchpad.net
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Dustin Kirkland <kirkland@canonical.com>
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
[tyhicks@linux.vnet.ibm.com: Removed extra newline, 80-char violation]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Lockdep reports the following valid-looking possible AB-BA deadlock with
global_auth_tok_list_mutex and keysig_list_mutex:
ecryptfs_new_file_context() ->
ecryptfs_copy_mount_wide_sigs_to_inode_sigs() ->
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
-> ecryptfs_add_keysig() ->
mutex_lock(&crypt_stat->keysig_list_mutex);
vs
ecryptfs_generate_key_packet_set() ->
mutex_lock(&crypt_stat->keysig_list_mutex);
-> ecryptfs_find_global_auth_tok_for_sig() ->
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
ie the two mutexes are taken in opposite orders in the two different
code paths. I'm not sure if this is a real bug where two threads could
actually hit the two paths in parallel and deadlock, but it at least
makes lockdep impossible to use with ecryptfs since this report triggers
every time and disables future lockdep reporting.
Since ecryptfs_add_keysig() is called only from the single callsite in
ecryptfs_copy_mount_wide_sigs_to_inode_sigs(), the simplest fix seems to
be to move the lock of keysig_list_mutex back up outside of the where
global_auth_tok_list_mutex is taken. This patch does that, and fixes
the lockdep report on my system (and ecryptfs still works OK).
The full output of lockdep fixed by this patch is:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.31-2-generic #14~rbd2
-------------------------------------------------------
gdm/2640 is trying to acquire lock:
(&mount_crypt_stat->global_auth_tok_list_mutex){+.+.+.}, at: [<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
but task is already holding lock:
(&crypt_stat->keysig_list_mutex){+.+.+.}, at: [<ffffffff81217728>] ecryptfs_generate_key_packet_set+0x58/0x2b0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&crypt_stat->keysig_list_mutex){+.+.+.}:
[<ffffffff8108c897>] check_prev_add+0x2a7/0x370
[<ffffffff8108cfc1>] validate_chain+0x661/0x750
[<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
[<ffffffff8121526a>] ecryptfs_add_keysig+0x5a/0xb0
[<ffffffff81213299>] ecryptfs_copy_mount_wide_sigs_to_inode_sigs+0x59/0xb0
[<ffffffff81214b06>] ecryptfs_new_file_context+0xa6/0x1a0
[<ffffffff8120e42a>] ecryptfs_initialize_file+0x4a/0x140
[<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
[<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
[<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
[<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
[<ffffffff8112d8d9>] do_sys_open+0x69/0x140
[<ffffffff8112d9f0>] sys_open+0x20/0x30
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
-> #0 (&mount_crypt_stat->global_auth_tok_list_mutex){+.+.+.}:
[<ffffffff8108c675>] check_prev_add+0x85/0x370
[<ffffffff8108cfc1>] validate_chain+0x661/0x750
[<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
[<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff812177d5>] ecryptfs_generate_key_packet_set+0x105/0x2b0
[<ffffffff81212f49>] ecryptfs_write_headers_virt+0xc9/0x120
[<ffffffff8121306d>] ecryptfs_write_metadata+0xcd/0x200
[<ffffffff8120e44b>] ecryptfs_initialize_file+0x6b/0x140
[<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
[<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
[<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
[<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
[<ffffffff8112d8d9>] do_sys_open+0x69/0x140
[<ffffffff8112d9f0>] sys_open+0x20/0x30
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
other info that might help us debug this:
2 locks held by gdm/2640:
#0: (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8113cb8b>] do_filp_open+0x3cb/0xae0
#1: (&crypt_stat->keysig_list_mutex){+.+.+.}, at: [<ffffffff81217728>] ecryptfs_generate_key_packet_set+0x58/0x2b0
stack backtrace:
Pid: 2640, comm: gdm Tainted: G C 2.6.31-2-generic #14~rbd2
Call Trace:
[<ffffffff8108b988>] print_circular_bug_tail+0xa8/0xf0
[<ffffffff8108c675>] check_prev_add+0x85/0x370
[<ffffffff81094912>] ? __module_text_address+0x12/0x60
[<ffffffff8108cfc1>] validate_chain+0x661/0x750
[<ffffffff81017275>] ? print_context_stack+0x85/0x140
[<ffffffff81089c68>] ? find_usage_backwards+0x38/0x160
[<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff8108b0b0>] ? check_usage_backwards+0x0/0xb0
[<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff8108c02c>] ? mark_held_locks+0x6c/0xa0
[<ffffffff81125b0d>] ? kmem_cache_alloc+0xfd/0x1a0
[<ffffffff8108c34d>] ? trace_hardirqs_on_caller+0x14d/0x190
[<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
[<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff812177d5>] ecryptfs_generate_key_packet_set+0x105/0x2b0
[<ffffffff81212f49>] ecryptfs_write_headers_virt+0xc9/0x120
[<ffffffff8121306d>] ecryptfs_write_metadata+0xcd/0x200
[<ffffffff81210240>] ? ecryptfs_init_persistent_file+0x60/0xe0
[<ffffffff8120e44b>] ecryptfs_initialize_file+0x6b/0x140
[<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
[<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
[<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
[<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
[<ffffffff8129a93e>] ? _raw_spin_unlock+0x5e/0xb0
[<ffffffff8155410b>] ? _spin_unlock+0x2b/0x40
[<ffffffff81139e9b>] ? getname+0x3b/0x240
[<ffffffff81148a5a>] ? alloc_fd+0xfa/0x140
[<ffffffff8112d8d9>] do_sys_open+0x69/0x140
[<ffffffff81553b8f>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff8112d9f0>] sys_open+0x20/0x30
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
In ecryptfs_destroy_inode(), inode_info->lower_file_mutex is locked,
and just after the mutex is unlocked, the code does:
kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
This means that if another context could possibly try to take the same
mutex as ecryptfs_destroy_inode(), then it could end up getting the
mutex just before the data structure containing the mutex is freed.
So any such use would be an obvious use-after-free bug (catchable with
slab poisoning or mutex debugging), and therefore the locking in
ecryptfs_destroy_inode() is not needed and can be dropped.
Similarly, in ecryptfs_destroy_crypt_stat(), crypt_stat->keysig_list_mutex
is locked, and then the mutex is unlocked just before the code does:
memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Therefore taking this mutex is similarly not necessary.
Removing this locking fixes false-positive lockdep reports such as the
following (and they are false-positives for exactly the same reason
that the locking is not needed):
=================================
[ INFO: inconsistent lock state ]
2.6.31-2-generic #14~rbd3
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/323 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&inode_info->lower_file_mutex){+.+.?.}, at: [<ffffffff81210d34>] ecryptfs_destroy_inode+0x34/0x100
{RECLAIM_FS-ON-W} state was registered at:
[<ffffffff8108c02c>] mark_held_locks+0x6c/0xa0
[<ffffffff8108c10f>] lockdep_trace_alloc+0xaf/0xe0
[<ffffffff81125a51>] kmem_cache_alloc+0x41/0x1a0
[<ffffffff8113117a>] get_empty_filp+0x7a/0x1a0
[<ffffffff8112dd46>] dentry_open+0x36/0xc0
[<ffffffff8121a36c>] ecryptfs_privileged_open+0x5c/0x2e0
[<ffffffff81210283>] ecryptfs_init_persistent_file+0xa3/0xe0
[<ffffffff8120e838>] ecryptfs_lookup_and_interpose_lower+0x278/0x380
[<ffffffff8120f97a>] ecryptfs_lookup+0x12a/0x250
[<ffffffff8113930a>] real_lookup+0xea/0x160
[<ffffffff8113afc8>] do_lookup+0xb8/0xf0
[<ffffffff8113b518>] __link_path_walk+0x518/0x870
[<ffffffff8113bd9c>] path_walk+0x5c/0xc0
[<ffffffff8113be5b>] do_path_lookup+0x5b/0xa0
[<ffffffff8113bfe7>] user_path_at+0x57/0xa0
[<ffffffff811340dc>] vfs_fstatat+0x3c/0x80
[<ffffffff8113424b>] vfs_stat+0x1b/0x20
[<ffffffff81134274>] sys_newstat+0x24/0x50
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 7811
hardirqs last enabled at (7811): [<ffffffff810c037f>] call_rcu+0x5f/0x90
hardirqs last disabled at (7810): [<ffffffff810c0353>] call_rcu+0x33/0x90
softirqs last enabled at (3764): [<ffffffff810631da>] __do_softirq+0x14a/0x220
softirqs last disabled at (3751): [<ffffffff8101440c>] call_softirq+0x1c/0x30
other info that might help us debug this:
2 locks held by kswapd0/323:
#0: (shrinker_rwsem){++++..}, at: [<ffffffff810f67ed>] shrink_slab+0x3d/0x190
#1: (&type->s_umount_key#35){.+.+..}, at: [<ffffffff811429a1>] prune_dcache+0xd1/0x1b0
stack backtrace:
Pid: 323, comm: kswapd0 Tainted: G C 2.6.31-2-generic #14~rbd3
Call Trace:
[<ffffffff8108ad6c>] print_usage_bug+0x18c/0x1a0
[<ffffffff8108aff0>] ? check_usage_forwards+0x0/0xc0
[<ffffffff8108bac2>] mark_lock_irq+0xf2/0x280
[<ffffffff8108bd87>] mark_lock+0x137/0x1d0
[<ffffffff81164710>] ? fsnotify_clear_marks_by_inode+0x30/0xf0
[<ffffffff8108bee6>] mark_irqflags+0xc6/0x1a0
[<ffffffff8108d337>] __lock_acquire+0x287/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
[<ffffffff8108d2e7>] ? __lock_acquire+0x237/0x430
[<ffffffff815526ad>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
[<ffffffff81164710>] ? fsnotify_clear_marks_by_inode+0x30/0xf0
[<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
[<ffffffff8129a91e>] ? _raw_spin_unlock+0x5e/0xb0
[<ffffffff81552b36>] mutex_lock_nested+0x46/0x60
[<ffffffff81210d34>] ecryptfs_destroy_inode+0x34/0x100
[<ffffffff81145d27>] destroy_inode+0x87/0xd0
[<ffffffff81146b4c>] generic_delete_inode+0x12c/0x1a0
[<ffffffff81145832>] iput+0x62/0x70
[<ffffffff811423c8>] dentry_iput+0x98/0x110
[<ffffffff81142550>] d_kill+0x50/0x80
[<ffffffff81142623>] prune_one_dentry+0xa3/0xc0
[<ffffffff811428b1>] __shrink_dcache_sb+0x271/0x290
[<ffffffff811429d9>] prune_dcache+0x109/0x1b0
[<ffffffff81142abf>] shrink_dcache_memory+0x3f/0x50
[<ffffffff810f68dd>] shrink_slab+0x12d/0x190
[<ffffffff810f9377>] balance_pgdat+0x4d7/0x640
[<ffffffff8104c4c0>] ? finish_task_switch+0x40/0x150
[<ffffffff810f63c0>] ? isolate_pages_global+0x0/0x60
[<ffffffff810f95f7>] kswapd+0x117/0x170
[<ffffffff810777a0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff810f94e0>] ? kswapd+0x0/0x170
[<ffffffff810773be>] kthread+0x9e/0xb0
[<ffffffff8101430a>] child_rip+0xa/0x20
[<ffffffff81013c90>] ? restore_args+0x0/0x30
[<ffffffff81077320>] ? kthread+0x0/0xb0
[<ffffffff81014300>] ? child_rip+0x0/0x20
Signed-off-by: Roland Dreier <roland@digitalvampire.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
The parse_tag_3_packet function does not check if the tag 3 packet contains a
encrypted key size larger than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES.
Signed-off-by: Ramon de Carvalho Valle <ramon@risesecurity.org>
[tyhicks@linux.vnet.ibm.com: Added printk newline and changed goto to out_free]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: stable@kernel.org (2.6.27 and 30)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tag 11 packets are stored in the metadata section of an eCryptfs file to
store the key signature(s) used to encrypt the file encryption key.
After extracting the packet length field to determine the key signature
length, a check is not performed to see if the length would exceed the
key signature buffer size that was passed into parse_tag_11_packet().
Thanks to Ramon de Carvalho Valle for finding this bug using fsfuzzer.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: stable@kernel.org (2.6.27 and 30)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move BKL into ->put_super from the only caller. A couple of
filesystems had trivial enough ->put_super (only kfree and NULLing of
s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
hugetlbfs, omfs, qnx4, shmem, all others got the full treatment. Most
of them probably don't need it, but I'd rather sort that out individually.
Preferably after all the other BKL pushdowns in that area.
[AV: original used to move lock_super() down as well; these changes are
removed since we don't do lock_super() at all in generic_shutdown_super()
now]
[AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This warning shows up on 64 bit builds:
fs/ecryptfs/inode.c:693: warning: comparison of distinct pointer types
lacks a cast
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
fs/ecryptfs/inode.c:670: warning: format '%d' expects type 'int', but argument 3 has type 'size_t'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: Dustin Kirkland <kirkland@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When using filename encryption with eCryptfs, the value of the symlink
in the lower filesystem is encrypted and stored as a Tag 70 packet.
This results in a longer symlink target than if the target value wasn't
encrypted.
Users were reporting these messages in their syslog:
[ 45.653441] ecryptfs_parse_tag_70_packet: max_packet_size is [56]; real
packet size is [51]
[ 45.653444] ecryptfs_decode_and_decrypt_filename: Could not parse tag
70 packet from filename; copying through filename as-is
This was due to bufsiz, one the arguments in readlink(), being used to
when allocating the buffer passed to the lower inode's readlink().
That symlink target may be very large, but when decoded and decrypted,
could end up being smaller than bufsize.
To fix this, the buffer passed to the lower inode's readlink() will
always be PATH_MAX in size when filename encryption is enabled. Any
necessary truncation occurs after the decoding and decrypting.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
This patch locks the lower directory inode's i_mutex before calling
lookup_one_len() to find the appropriate dentry in the lower filesystem.
This bug was found thanks to the warning set in commit 2f9092e1.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
A feature was added to the eCryptfs umount helper to automatically
unlink the keys used for an eCryptfs mount from the kernel keyring upon
umount. This patch keeps the unrecognized mount option warnings for
ecryptfs_unlink_sigs out of the logs.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
ecryptfs_passthrough is a mount option that allows eCryptfs to allow
data to be written to non-eCryptfs files in the lower filesystem. The
passthrough option was causing data corruption due to it not always
being treated as a non-eCryptfs file.
The first 8 bytes of an eCryptfs file contains the decrypted file size.
This value was being written to the non-eCryptfs files, too. Also,
extra 0x00 characters were being written to make the file size a
multiple of PAGE_CACHE_SIZE.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
The filename encryption key signature is not properly displayed in
/proc/mounts. The "ecryptfs_sig=" mount option name is displayed for
all global authentication tokens, included those for filename keys.
This patch checks the global authentication token flags to determine if
the key is a FEKEK or FNEK and prints the appropriate mount option name
before the signature.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
If data is NULL, msg_ctx->msg is set to NULL and then dereferenced
afterwards. ecryptfs_send_raw_message() is the only place that
ecryptfs_send_miscdev() is called with data being NULL, but the only
caller of that function (ecryptfs_process_helo()) is never called. In
short, there is currently no way to trigger the NULL pointer
dereference.
This patch removes the two unused functions and modifies
ecryptfs_send_miscdev() to remove the NULL dereferences.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Copies the lower inode attributes to the upper inode before passing the
upper inode to d_instantiate(). This is important for
security_d_instantiate().
The problem was discovered by a user seeing SELinux denials like so:
type=AVC msg=audit(1236812817.898:47): avc: denied { 0x100000 } for
pid=3584 comm="httpd" name="testdir" dev=ecryptfs ino=943872
scontext=root:system_r:httpd_t:s0
tcontext=root:object_r:httpd_sys_content_t:s0 tclass=file
Notice target class is file while testdir is really a directory,
confusing the permission translation (0x100000) due to the wrong i_mode.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
If ecryptfs_encrypted_view or ecryptfs_xattr_metadata were being
specified as mount options, a NULL pointer dereference of crypt_stat
was possible during lookup.
This patch moves the crypt_stat assignment into
ecryptfs_lookup_and_interpose_lower(), ensuring that crypt_stat
will not be NULL before we attempt to dereference it.
Thanks to Dan Carpenter and his static analysis tool, smatch, for
finding this bug.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Acked-by: Dustin Kirkland <kirkland@canonical.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When allocating the memory used to store the eCryptfs header contents, a
single, zeroed page was being allocated with get_zeroed_page().
However, the size of an eCryptfs header is either PAGE_CACHE_SIZE or
ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE (8192), whichever is larger, and is
stored in the file's private_data->crypt_stat->num_header_bytes_at_front
field.
ecryptfs_write_metadata_to_contents() was using
num_header_bytes_at_front to decide how many bytes should be written to
the lower filesystem for the file header. Unfortunately, at least 8K
was being written from the page, despite the chance of the single,
zeroed page being smaller than 8K. This resulted in random areas of
kernel memory being written between the 0x1000 and 0x1FFF bytes offsets
in the eCryptfs file headers if PAGE_SIZE was 4K.
This patch allocates a variable number of pages, calculated with
num_header_bytes_at_front, and passes the number of allocated pages
along to ecryptfs_write_metadata_to_contents().
Thanks to Florian Streibelt for reporting the data leak and working with
me to find the problem. 2.6.28 is the only kernel release with this
vulnerability. Corresponds to CVE-2009-0787
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Acked-by: Dustin Kirkland <kirkland@canonical.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Eugene Teo <eugeneteo@kernel.sg>
Cc: Greg KH <greg@kroah.com>
Cc: dann frazier <dannf@dannf.org>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Florian Streibelt <florian@f-streibelt.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
eCryptfs has file encryption keys (FEK), file encryption key encryption
keys (FEKEK), and filename encryption keys (FNEK). The per-file FEK is
encrypted with one or more FEKEKs and stored in the header of the
encrypted file. I noticed that the FEK is also being encrypted by the
FNEK. This is a problem if a user wants to use a different FNEK than
their FEKEK, as their file contents will still be accessible with the
FNEK.
This is a minimalistic patch which prevents the FNEKs signatures from
being copied to the inode signatures list. Ultimately, it keeps the FEK
from being encrypted with a FNEK.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Acked-by: Dustin Kirkland <kirkland@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The addition of filename encryption caused a regression in unencrypted
filename symlink support. ecryptfs_copy_filename() is used when dealing
with unencrypted filenames and it reported that the new, copied filename
was a character longer than it should have been.
This caused the return value of readlink() to count the NULL byte of the
symlink target. Most applications don't care about the extra NULL byte,
but a version control system (bzr) helped in discovering the bug.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Arguments lower_dentry and ecryptfs_dentry in ecryptfs_create_underlying_file()
have been merged into dentry, now fix it.
Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Flesh out the comments for ecryptfs_decode_from_filename(). Remove the
return condition, since it is always 0.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Correct several format string data type specifiers. Correct filename size
data types; they should be size_t rather than int when passed as
parameters to some other functions (although note that the filenames will
never be larger than int).
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
%Z is a gcc-ism. Using %z instead.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enable mount-wide filename encryption by providing the Filename Encryption
Key (FNEK) signature as a mount option. Note that the ecryptfs-utils
userspace package versions 61 or later support this option.
When mounting with ecryptfs-utils version 61 or later, the mount helper
will detect the availability of the passphrase-based filename encryption
in the kernel (via the eCryptfs sysfs handle) and query the user
interactively as to whether or not he wants to enable the feature for the
mount. If the user enables filename encryption, the mount helper will
then prompt for the FNEK signature that the user wishes to use, suggesting
by default the signature for the mount passphrase that the user has
already entered for encrypting the file contents.
When not using the mount helper, the user can specify the signature for
the passphrase key with the ecryptfs_fnek_sig= mount option. This key
must be available in the user's keyring. The mount helper usually takes
care of this step. If, however, the user is not mounting with the mount
helper, then he will need to enter the passphrase key into his keyring
with some other utility prior to mounting, such as ecryptfs-manager.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make the requisite modifications to ecryptfs_filldir(), ecryptfs_lookup(),
and ecryptfs_readlink() to call out to filename encryption functions.
Propagate filename encryption policy flags from mount-wide crypt_stat to
inode crypt_stat.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These functions support encrypting and encoding the filename contents.
The encrypted filename contents may consist of any ASCII characters. This
patch includes a custom encoding mechanism to map the ASCII characters to
a reduced character set that is appropriate for filenames.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Extensions to the header file to support filename encryption.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patchset implements filename encryption via a passphrase-derived
mount-wide Filename Encryption Key (FNEK) specified as a mount parameter.
Each encrypted filename has a fixed prefix indicating that eCryptfs should
try to decrypt the filename. When eCryptfs encounters this prefix, it
decodes the filename into a tag 70 packet and then decrypts the packet
contents using the FNEK, setting the filename to the decrypted filename.
Both unencrypted and encrypted filenames can reside in the same lower
filesystem.
Because filename encryption expands the length of the filename during the
encoding stage, eCryptfs will not properly handle filenames that are
already near the maximum filename length.
In the present implementation, eCryptfs must be able to produce a match
against the lower encrypted and encoded filename representation when given
a plaintext filename. Therefore, two files having the same plaintext name
will encrypt and encode into the same lower filename if they are both
encrypted using the same FNEK. This can be changed by finding a way to
replace the prepended bytes in the blocked-aligned filename with random
characters; they are hashes of the FNEK right now, so that it is possible
to deterministically map from a plaintext filename to an encrypted and
encoded filename in the lower filesystem. An implementation using random
characters will have to decode and decrypt every single directory entry in
any given directory any time an event occurs wherein the VFS needs to
determine whether a particular file exists in the lower directory and the
decrypted and decoded filenames have not yet been extracted for that
directory.
Thanks to Tyler Hicks and David Kleikamp for assistance in the development
of this patchset.
This patch:
A tag 70 packet contains a filename encrypted with a Filename Encryption
Key (FNEK). This patch implements functions for writing and parsing tag
70 packets. This patch also adds definitions and extends structures to
support filename encryption.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
inotify: fix type errors in interfaces
fix breakage in reiserfs_new_inode()
fix the treatment of jfs special inodes
vfs: remove duplicate code in get_fs_type()
add a vfs_fsync helper
sys_execve and sys_uselib do not call into fsnotify
zero i_uid/i_gid on inode allocation
inode->i_op is never NULL
ntfs: don't NULL i_op
isofs check for NULL ->i_op in root directory is dead code
affs: do not zero ->i_op
kill suid bit only for regular files
vfs: lseek(fd, 0, SEEK_CUR) race condition
Fsync currently has a fdatawrite/fdatawait pair around the method call,
and a mutex_lock/unlock of the inode mutex. All callers of fsync have
to duplicate this, but we have a few and most of them don't quite get
it right. This patch adds a new vfs_fsync that takes care of this.
It's a little more complicated as usual as ->fsync might get a NULL file
pointer and just a dentry from nfsd, but otherwise gets afile and we
want to take the mapping and file operations from it when it is there.
Notes on the fsync callers:
- ecryptfs wasn't calling filemap_fdatawrite / filemap_fdatawait on the
lower file
- coda wasn't calling filemap_fdatawrite / filemap_fdatawait on the host
file, and returning 0 when ->fsync was missing
- shm wasn't calling either filemap_fdatawrite / filemap_fdatawait nor
taking i_mutex. Now given that shared memory doesn't have disk
backing not doing anything in fsync seems fine and I left it out of
the vfs_fsync conversion for now, but in that case we might just
not pass it through to the lower file at all but just call the no-op
simple_sync_file directly.
[and now actually export vfs_fsync]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We used to have rather schizophrenic set of checks for NULL ->i_op even
though it had been eliminated years ago. You'd need to go out of your
way to set it to NULL explicitly _and_ a bunch of code would die on
such inodes anyway. After killing two remaining places that still
did that bogosity, all that crap can go away.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
With the write_begin/write_end aops, page_symlink was broken because it
could no longer pass a GFP_NOFS type mask into the point where the
allocations happened. They are done in write_begin, which would always
assume that the filesystem can be entered from reclaim. This bug could
cause filesystem deadlocks.
The funny thing with having a gfp_t mask there is that it doesn't really
allow the caller to arbitrarily tinker with the context in which it can be
called. It couldn't ever be GFP_ATOMIC, for example, because it needs to
take the page lock. The only thing any callers care about is __GFP_FS
anyway, so turn that into a single flag.
Add a new flag for write_begin, AOP_FLAG_NOFS. Filesystems can now act on
this flag in their write_begin function. Change __grab_cache_page to
accept a nofs argument as well, to honour that flag (while we're there,
change the name to grab_cache_page_write_begin which is more instructive
and does away with random leading underscores).
This is really a more flexible way to go in the end anyway -- if a
filesystem happens to want any extra allocations aside from the pagecache
ones in ints write_begin function, it may now use GFP_KERNEL (rather than
GFP_NOFS) for common case allocations (eg. ocfs2_alloc_write_ctxt, for a
random example).
[kosaki.motohiro@jp.fujitsu.com: fix ubifs]
[kosaki.motohiro@jp.fujitsu.com: fix fuse]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Cleaned up the calling convention: just pass in the AOP flags
untouched to the grab_cache_page_write_begin() function. That
just simplifies everybody, and may even allow future expansion of the
logic. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The result from readlink is being used to index into the link name
buffer without checking whether it is a valid length. If readlink
returns an error this will fault or cause memory corruption.
Cc: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: Dustin Kirkland <kirkland@canonical.com>
Cc: ecryptfs-devel@lists.launchpad.net
Signed-off-by: Duane Griffin <duaneg@dghda.com>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Acked-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Conflicts:
fs/nfsd/nfs4recover.c
Manually fixed above to use new creds API functions, e.g.
nfs4_save_creds().
Signed-off-by: James Morris <jmorris@namei.org>
The user_ns is moved from nsproxy to user_struct, so that a struct
cred by itself is sufficient to determine access (which it otherwise
would not be). Corresponding ecryptfs fixes (by David Howells) are
here as well.
Fix refcounting. The following rules now apply:
1. The task pins the user struct.
2. The user struct pins its user namespace.
3. The user namespace pins the struct user which created it.
User namespaces are cloned during copy_creds(). Unsharing a new user_ns
is no longer possible. (We could re-add that, but it'll cause code
duplication and doesn't seem useful if PAM doesn't need to clone user
namespaces).
When a user namespace is created, its first user (uid 0) gets empty
keyrings and a clean group_info.
This incorporates a previous patch by David Howells. Here
is his original patch description:
>I suggest adding the attached incremental patch. It makes the following
>changes:
>
> (1) Provides a current_user_ns() macro to wrap accesses to current's user
> namespace.
>
> (2) Fixes eCryptFS.
>
> (3) Renames create_new_userns() to create_user_ns() to be more consistent
> with the other associated functions and because the 'new' in the name is
> superfluous.
>
> (4) Moves the argument and permission checks made for CLONE_NEWUSER to the
> beginning of do_fork() so that they're done prior to making any attempts
> at allocation.
>
> (5) Calls create_user_ns() after prepare_creds(), and gives it the new creds
> to fill in rather than have it return the new root user. I don't imagine
> the new root user being used for anything other than filling in a cred
> struct.
>
> This also permits me to get rid of a get_uid() and a free_uid(), as the
> reference the creds were holding on the old user_struct can just be
> transferred to the new namespace's creator pointer.
>
> (6) Makes create_user_ns() reset the UIDs and GIDs of the creds under
> preparation rather than doing it in copy_creds().
>
>David
>Signed-off-by: David Howells <dhowells@redhat.com>
Changelog:
Oct 20: integrate dhowells comments
1. leave thread_keyring alone
2. use current_user_ns() in set_user()
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
I have received some reports of out-of-memory errors on some older AMD
architectures. These errors are what I would expect to see if
crypt_stat->key were split between two separate pages. eCryptfs should
not assume that any of the memory sent through virt_to_scatterlist() is
all contained in a single page, and so this patch allocates two
scatterlist structs instead of one when processing keys. I have received
confirmation from one person affected by this bug that this patch resolves
the issue for him, and so I am submitting it for inclusion in a future
stable release.
Note that virt_to_scatterlist() runs sg_init_table() on the scatterlist
structs passed to it, so the calls to sg_init_table() in
decrypt_passphrase_encrypted_session_key() are redundant.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Reported-by: Paulo J. S. Silva <pjssilva@ime.usp.br>
Cc: "Leon Woestenberg" <leon.woestenberg@gmail.com>
Cc: Tim Gardner <tim.gardner@canonical.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.
The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.
Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Mike Halcrow <mhalcrow@us.ibm.com>
Cc: Phillip Hellewell <phillip@hellewell.homeip.net>
Cc: ecryptfs-devel@lists.sourceforge.net
Signed-off-by: James Morris <jmorris@namei.org>
When ecryptfs allocates space to write crypto headers into, before copying
it out to file headers or to xattrs, it looks at the value of
crypt_stat->num_header_bytes_at_front to determine how much space it
needs. This is also used as the file offset to the actual encrypted data,
so for xattr-stored crypto info, the value was zero.
So, we kzalloc'd 0 bytes, and then ran off to write to that memory.
(Which returned as ZERO_SIZE_PTR, so we explode quickly).
The right answer is to always allocate a page to write into; the current
code won't ever write more than that (this is enforced by the
(PAGE_CACHE_SIZE - offset) length in the call to
ecryptfs_generate_key_packet_set). To be explicit about this, we now send
in a "max" parameter, rather than magically using PAGE_CACHE_SIZE there.
Also, since the pointer we pass down the callchain eventually gets the
virt_to_page() treatment, we should be using a alloc_page variant, not
kzalloc (see also 7fcba05437)
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The netlink transport code has not worked for a while and the miscdev
transport is a simpler solution. This patch removes the netlink code and
makes the miscdev transport the only eCryptfs kernel to userspace
transport.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <kirkland@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert ecryptfs to use write_begin/write_end
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
