linux/fs, branch v3.9.9

UBIFS: fix a horrid bug

2013-07-03T17:55:36Z

commit 605c912bb843c024b1ed173dc427cd5c08e5d54d upstream. Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are in the middle of 'ubifs_readdir()'. This means that 'file->private_data' can be freed while 'ubifs_readdir()' uses it, and this is a very bad bug: not only 'ubifs_readdir()' can return garbage, but this may corrupt memory and lead to all kinds of problems like crashes an security holes. This patch fixes the problem by using the 'file->f_version' field, which '->llseek()' always unconditionally sets to zero. We set it to 1 in 'ubifs_readdir()' and whenever we detect that it became 0, we know there was a seek and it is time to clear the state saved in 'file->private_data'. I tested this patch by writing a user-space program which runds readdir and seek in parallell. I could easily crash the kernel without these patches, but could not crash it with these patches. Reported-by: Al Viro Tested-by: Artem Bityutskiy Signed-off-by: Artem Bityutskiy Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

UBIFS: prepare to fix a horrid bug

2013-07-03T17:55:28Z

commit 33f1a63ae84dfd9ad298cf275b8f1887043ced36 upstream. Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are in the middle of 'ubifs_readdir()'. First of all, this means that 'file->private_data' can be freed while 'ubifs_readdir()' uses it. But this particular patch does not fix the problem. This patch is only a preparation, and the fix will follow next. In this patch we make 'ubifs_readdir()' stop using 'file->f_pos' directly, because 'file->f_pos' can be changed by '->llseek()' at any point. This may lead 'ubifs_readdir()' to returning inconsistent data: directory entry names may correspond to incorrect file positions. So here we introduce a local variable 'pos', read 'file->f_pose' once at very the beginning, and then stick to 'pos'. The result of this is that when 'ubifs_dir_llseek()' changes 'file->f_pos' while we are in the middle of 'ubifs_readdir()', the latter "wins". Reported-by: Al Viro Tested-by: Artem Bityutskiy Signed-off-by: Artem Bityutskiy Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

perf: Disable monitoring on setuid processes for regular users

2013-07-03T17:55:22Z

commit 2976b10f05bd7f6dab9f9e7524451ddfed656a89 upstream. There was a a bug in setup_new_exec(), whereby the test to disabled perf monitoring was not correct because the new credentials for the process were not yet committed and therefore the get_dumpable() test was never firing. The patch fixes the problem by moving the perf_event test until after the credentials are committed. Signed-off-by: Stephane Eranian Tested-by: Jiri Olsa Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

libceph: wrap auth ops in wrapper functions

2013-06-20T19:01:32Z

commit 27859f9773e4a0b2042435b13400ee2c891a61f4 upstream. Use wrapper functions that check whether the auth op exists so that callers do not need a bunch of conditional checks. Simplifies the external interface. Signed-off-by: Sage Weil Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman

libceph: add update_authorizer auth method

2013-06-20T19:01:32Z

commit 0bed9b5c523d577378b6f83eab5835fe30c27208 upstream. Currently the messenger calls out to a get_authorizer con op, which will create a new authorizer if it doesn't yet have one. In the meantime, when we rotate our service keys, the authorizer doesn't get updated. Eventually it will be rejected by the server on a new connection attempt and get invalidated, and we will then rebuild a new authorizer, but this is not ideal. Instead, if we do have an authorizer, call a new update_authorizer op that will verify that the current authorizer is using the latest secret. If it is not, we will build a new one that does. This avoids the transient failure. This fixes one of the sorry sequence of events for bug http://tracker.ceph.com/issues/4282 Signed-off-by: Sage Weil Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman

kmsg: honor dmesg_restrict sysctl on /dev/kmsg

2013-06-20T19:01:29Z

commit 637241a900cbd982f744d44646b48a273d609b34 upstream. The dmesg_restrict sysctl currently covers the syslog method for access dmesg, however /dev/kmsg isn't covered by the same protections. Most people haven't noticed because util-linux dmesg(1) defaults to using the syslog method for access in older versions. With util-linux dmesg(1) defaults to reading directly from /dev/kmsg. To fix /dev/kmsg, let's compare the existing interfaces and what they allow: - /proc/kmsg allows: - open (SYSLOG_ACTION_OPEN) if CAP_SYSLOG since it uses a destructive single-reader interface (SYSLOG_ACTION_READ). - everything, after an open. - syslog syscall allows: - anything, if CAP_SYSLOG. - SYSLOG_ACTION_READ_ALL and SYSLOG_ACTION_SIZE_BUFFER, if dmesg_restrict==0. - nothing else (EPERM). The use-cases were: - dmesg(1) needs to do non-destructive SYSLOG_ACTION_READ_ALLs. - sysklog(1) needs to open /proc/kmsg, drop privs, and still issue the destructive SYSLOG_ACTION_READs. AIUI, dmesg(1) is moving to /dev/kmsg, and systemd-journald doesn't clear the ring buffer. Based on the comments in devkmsg_llseek, it sounds like actions besides reading aren't going to be supported by /dev/kmsg (i.e. SYSLOG_ACTION_CLEAR), so we have a strict subset of the non-destructive syslog syscall actions. To this end, move the check as Josh had done, but also rename the constants to reflect their new uses (SYSLOG_FROM_CALL becomes SYSLOG_FROM_READER, and SYSLOG_FROM_FILE becomes SYSLOG_FROM_PROC). SYSLOG_FROM_READER allows non-destructive actions, and SYSLOG_FROM_PROC allows destructive actions after a capabilities-constrained SYSLOG_ACTION_OPEN check. - /dev/kmsg allows: - open if CAP_SYSLOG or dmesg_restrict==0 - reading/polling, after open Addresses https://bugzilla.redhat.com/show_bug.cgi?id=903192 [akpm@linux-foundation.org: use pr_warn_once()] Signed-off-by: Kees Cook Reported-by: Christian Kujau Tested-by: Josh Boyer Cc: Kay Sievers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

ceph: ceph_pagelist_append might sleep while atomic

2013-06-20T19:01:27Z

commit 39be95e9c8c0b5668c9f8806ffe29bf9f4bc0f40 upstream. Ceph's encode_caps_cb() worked hard to not call __page_cache_alloc() while holding a lock, but it's spoiled because ceph_pagelist_addpage() always calls kmap(), which might sleep. Here's the result: [13439.295457] ceph: mds0 reconnect start [13439.300572] BUG: sleeping function called from invalid context at include/linux/highmem.h:58 [13439.309243] in_atomic(): 1, irqs_disabled(): 0, pid: 12059, name: kworker/1:1 . . . [13439.376225] Call Trace: [13439.378757] [] __might_sleep+0xfc/0x110 [13439.384353] [] ceph_pagelist_append+0x120/0x1b0 [libceph] [13439.391491] [] ceph_encode_locks+0x89/0x190 [ceph] [13439.398035] [] ? _raw_spin_lock+0x49/0x50 [13439.403775] [] ? lock_flocks+0x15/0x20 [13439.409277] [] encode_caps_cb+0x41f/0x4a0 [ceph] [13439.415622] [] ? igrab+0x28/0x70 [13439.420610] [] ? iterate_session_caps+0xe8/0x250 [ceph] [13439.427584] [] iterate_session_caps+0x115/0x250 [ceph] [13439.434499] [] ? set_request_path_attr+0x2d0/0x2d0 [ceph] [13439.441646] [] send_mds_reconnect+0x238/0x450 [ceph] [13439.448363] [] ? ceph_mdsmap_decode+0x5e2/0x770 [ceph] [13439.455250] [] check_new_map+0x352/0x500 [ceph] [13439.461534] [] ceph_mdsc_handle_map+0x1bd/0x260 [ceph] [13439.468432] [] ? mutex_unlock+0xe/0x10 [13439.473934] [] extra_mon_dispatch+0x22/0x30 [ceph] [13439.480464] [] dispatch+0xbc/0x110 [libceph] [13439.486492] [] process_message+0x1ad/0x1d0 [libceph] [13439.493190] [] ? read_partial_message+0x3e8/0x520 [libceph] . . . [13439.587132] ceph: mds0 reconnect success [13490.720032] ceph: mds0 caps stale [13501.235257] ceph: mds0 recovery completed [13501.300419] ceph: mds0 caps renewed Fix it up by encoding locks into a buffer first, and when the number of encoded locks is stable, copy that into a ceph_pagelist. [elder@inktank.com: abbreviated the stack info a bit.] Signed-off-by: Jim Schutt Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman

ceph: add cpu_to_le32() calls when encoding a reconnect capability

2013-06-20T19:01:27Z

commit c420276a532a10ef59849adc2681f45306166b89 upstream. In his review, Alex Elder mentioned that he hadn't checked that num_fcntl_locks and num_flock_locks were properly decoded on the server side, from a le32 over-the-wire type to a cpu type. I checked, and AFAICS it is done; those interested can consult Locker::_do_cap_update() in src/mds/Locker.cc and src/include/encoding.h in the Ceph server code (git://github.com/ceph/ceph). I also checked the server side for flock_len decoding, and I believe that also happens correctly, by virtue of having been declared __le32 in struct ceph_mds_cap_reconnect, in src/include/ceph_fs.h. Signed-off-by: Jim Schutt Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman

eCryptfs: Check return of filemap_write_and_wait during fsync

2013-06-13T17:49:32Z

commit bc5abcf7e411b889f73ea2a90439071a0f451011 upstream. Error out of ecryptfs_fsync() if filemap_write_and_wait() fails. Signed-off-by: Tyler Hicks Cc: Paul Taysom Cc: Olof Johansson Signed-off-by: Greg Kroah-Hartman

ecryptfs: fixed msync to flush data

2013-06-13T17:49:31Z

commit c15cddd900e867c5adfb3c79596479dc5975f743 upstream. When msync is called on a memory mapped file, that data is not flushed to the disk. In Linux, msync calls fsync for the file. For ecryptfs, fsync just calls the lower level file system's fsync. Changed the ecryptfs fsync code to call filemap_write_and_wait before calling the lower level fsync. Addresses the problem described in http://crbug.com/239536 Signed-off-by: Paul Taysom Signed-off-by: Tyler Hicks Signed-off-by: Greg Kroah-Hartman