kernel/linux.git/include/linux, branch v3.14.19

vfs: add d_is_dir()

2014-09-17T16:19:27+00:00

commit 44b1d53043c482225196e8a9cd9f35163a1b3336 upstream. Add d_is_dir(dentry) helper which is analogous to S_ISDIR(). To avoid confusion, rename d_is_directory() to d_can_lookup(). Signed-off-by: Miklos Szeredi Reviewed-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

mnt: Correct permission checks in do_remount

2014-09-17T16:19:21+00:00

commit 9566d6742852c527bf5af38af5cbb878dad75705 upstream. While invesgiating the issue where in "mount --bind -oremount,ro ..." would result in later "mount --bind -oremount,rw" succeeding even if the mount started off locked I realized that there are several additional mount flags that should be locked and are not. In particular MNT_NOSUID, MNT_NODEV, MNT_NOEXEC, and the atime flags in addition to MNT_READONLY should all be locked. These flags are all per superblock, can all be changed with MS_BIND, and should not be changable if set by a more privileged user. The following additions to the current logic are added in this patch. - nosuid may not be clearable by a less privileged user. - nodev may not be clearable by a less privielged user. - noexec may not be clearable by a less privileged user. - atime flags may not be changeable by a less privileged user. The logic with atime is that always setting atime on access is a global policy and backup software and auditing software could break if atime bits are not updated (when they are configured to be updated), and serious performance degradation could result (DOS attack) if atime updates happen when they have been explicitly disabled. Therefore an unprivileged user should not be able to mess with the atime bits set by a more privileged user. The additional restrictions are implemented with the addition of MNT_LOCK_NOSUID, MNT_LOCK_NODEV, MNT_LOCK_NOEXEC, and MNT_LOCK_ATIME mnt flags. Taken together these changes and the fixes for MNT_LOCK_READONLY should make it safe for an unprivileged user to create a user namespace and to call "mount --bind -o remount,... ..." without the danger of mount flags being changed maliciously. Acked-by: Serge E. Hallyn Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

mnt: Only change user settable mount flags in remount

2014-09-17T16:19:21+00:00

commit a6138db815df5ee542d848318e5dae681590fccd upstream. Kenton Varda discovered that by remounting a read-only bind mount read-only in a user namespace the MNT_LOCK_READONLY bit would be cleared, allowing an unprivileged user to the remount a read-only mount read-write. Correct this by replacing the mask of mount flags to preserve with a mask of mount flags that may be changed, and preserve all others. This ensures that any future bugs with this mask and remount will fail in an easy to detect way where new mount flags simply won't change. Acked-by: Serge E. Hallyn Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

CAPABILITIES: remove undefined caps from all processes

2014-09-17T16:19:09+00:00

commit 7d8b6c63751cfbbe5eef81a48c22978b3407a3ad upstream. This is effectively a revert of 7b9a7ec565505699f503b4fcf61500dceb36e744 plus fixing it a different way... We found, when trying to run an application from an application which had dropped privs that the kernel does security checks on undefined capability bits. This was ESPECIALLY difficult to debug as those undefined bits are hidden from /proc/$PID/status. Consider a root application which drops all capabilities from ALL 4 capability sets. We assume, since the application is going to set eff/perm/inh from an array that it will clear not only the defined caps less than CAP_LAST_CAP, but also the higher 28ish bits which are undefined future capabilities. The BSET gets cleared differently. Instead it is cleared one bit at a time. The problem here is that in security/commoncap.c::cap_task_prctl() we actually check the validity of a capability being read. So any task which attempts to 'read all things set in bset' followed by 'unset all things set in bset' will not even attempt to unset the undefined bits higher than CAP_LAST_CAP. So the 'parent' will look something like: CapInh: 0000000000000000 CapPrm: 0000000000000000 CapEff: 0000000000000000 CapBnd: ffffffc000000000 All of this 'should' be fine. Given that these are undefined bits that aren't supposed to have anything to do with permissions. But they do... So lets now consider a task which cleared the eff/perm/inh completely and cleared all of the valid caps in the bset (but not the invalid caps it couldn't read out of the kernel). We know that this is exactly what the libcap-ng library does and what the go capabilities library does. They both leave you in that above situation if you try to clear all of you capapabilities from all 4 sets. If that root task calls execve() the child task will pick up all caps not blocked by the bset. The bset however does not block bits higher than CAP_LAST_CAP. So now the child task has bits in eff which are not in the parent. These are 'meaningless' undefined bits, but still bits which the parent doesn't have. The problem is now in cred_cap_issubset() (or any operation which does a subset test) as the child, while a subset for valid cap bits, is not a subset for invalid cap bits! So now we set durring commit creds that the child is not dumpable. Given it is 'more priv' than its parent. It also means the parent cannot ptrace the child and other stupidity. The solution here: 1) stop hiding capability bits in status This makes debugging easier! 2) stop giving any task undefined capability bits. it's simple, it you don't put those invalid bits in CAP_FULL_SET you won't get them in init and you won't get them in any other task either. This fixes the cap_issubset() tests and resulting fallout (which made the init task in a docker container untraceable among other things) 3) mask out undefined bits when sys_capset() is called as it might use ~0, ~0 to denote 'all capabilities' for backward/forward compatibility. This lets 'capsh --caps="all=eip" -- -c /bin/bash' run. 4) mask out undefined bit when we read a file capability off of disk as again likely all bits are set in the xattr for forward/backward compatibility. This lets 'setcap all+pe /bin/bash; /bin/bash' run Signed-off-by: Eric Paris Reviewed-by: Kees Cook Cc: Andrew Vagin Cc: Andrew G. Morgan Cc: Serge E. Hallyn Cc: Kees Cook Cc: Steve Grubb Cc: Dan Walsh Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

tpm: Provide a generic means to override the chip returned timeouts

2014-09-17T16:19:08+00:00

commit 8e54caf407b98efa05409e1fee0e5381abd2b088 upstream. Some Atmel TPMs provide completely wrong timeouts from their TPM_CAP_PROP_TIS_TIMEOUT query. This patch detects that and returns new correct values via a DID/VID table in the TIS driver. Tested on ARM using an AT97SC3204T FW version 37.16 [PHuewe: without this fix these 'broken' Atmel TPMs won't function on older kernels] Signed-off-by: "Berg, Christopher" Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Peter Huewe

svcrdma: Select NFSv4.1 backchannel transport based on forward channel

2014-09-05T23:34:18+00:00

commit 3c45ddf823d679a820adddd53b52c6699c9a05ac upstream. The current code always selects XPRT_TRANSPORT_BC_TCP for the back channel, even when the forward channel was not TCP (eg, RDMA). When a 4.1 mount is attempted with RDMA, the server panics in the TCP BC code when trying to send CB_NULL. Instead, construct the transport protocol number from the forward channel transport or'd with XPRT_TRANSPORT_BC. Transports that do not support bi-directional RPC will not have registered a "BC" transport, causing create_backchannel_client() to fail immediately. Fixes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=265 Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

jbd2: fix descriptor block size handling errors with journal_csum

2014-09-05T23:34:17+00:00

commit db9ee220361de03ee86388f9ea5e529eaad5323c upstream. It turns out that there are some serious problems with the on-disk format of journal checksum v2. The foremost is that the function to calculate descriptor tag size returns sizes that are too big. This causes alignment issues on some architectures and is compounded by the fact that some parts of jbd2 use the structure size (incorrectly) to determine the presence of a 64bit journal instead of checking the feature flags. Therefore, introduce journal checksum v3, which enlarges the descriptor block tag format to allow for full 32-bit checksums of journal blocks, fix the journal tag function to return the correct sizes, and fix the jbd2 recovery code to use feature flags to determine 64bitness. Add a few function helpers so we don't have to open-code quite so many pieces. Switching to a 16-byte block size was found to increase journal size overhead by a maximum of 0.1%, to convert a 32-bit journal with no checksumming to a 32-bit journal with checksum v3 enabled. Signed-off-by: Darrick J. Wong Reported-by: TR Reardon Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

printk: rename printk_sched to printk_deferred

2014-08-07T21:52:37+00:00

commit aac74dc495456412c4130a1167ce4beb6c1f0b38 upstream. After learning we'll need some sort of deferred printk functionality in the timekeeping core, Peter suggested we rename the printk_sched function so it can be reused by needed subsystems. This only changes the function name. No logic changes. Signed-off-by: John Stultz Reviewed-by: Steven Rostedt Cc: Jan Kara Cc: Peter Zijlstra Cc: Jiri Bohac Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

libata: introduce ata_host->n_tags to avoid oops on SAS controllers

2014-07-31T19:52:54+00:00

commit 1a112d10f03e83fb3a2fdc4c9165865dec8a3ca6 upstream. 1871ee134b73 ("libata: support the ata host which implements a queue depth less than 32") directly used ata_port->scsi_host->can_queue from ata_qc_new() to determine the number of tags supported by the host; unfortunately, SAS controllers doing SATA don't initialize ->scsi_host leading to the following oops. BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 IP: [] ata_qc_new_init+0x188/0x1b0 PGD 0 Oops: 0002 [#1] SMP Modules linked in: isci libsas scsi_transport_sas mgag200 drm_kms_helper ttm CPU: 1 PID: 518 Comm: udevd Not tainted 3.16.0-rc6+ #62 Hardware name: Intel Corporation S2600CO/S2600CO, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013 task: ffff880c1a00b280 ti: ffff88061a000000 task.ti: ffff88061a000000 RIP: 0010:[] [] ata_qc_new_init+0x188/0x1b0 RSP: 0018:ffff88061a003ae8 EFLAGS: 00010012 RAX: 0000000000000001 RBX: ffff88000241ca80 RCX: 00000000000000fa RDX: 0000000000000020 RSI: 0000000000000020 RDI: ffff8806194aa298 RBP: ffff88061a003ae8 R08: ffff8806194a8000 R09: 0000000000000000 R10: 0000000000000000 R11: ffff88000241ca80 R12: ffff88061ad58200 R13: ffff8806194aa298 R14: ffffffff814e67a0 R15: ffff8806194a8000 FS: 00007f3ad7fe3840(0000) GS:ffff880627620000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000058 CR3: 000000061a118000 CR4: 00000000001407e0 Stack: ffff88061a003b20 ffffffff814e96e1 ffff88000241ca80 ffff88061ad58200 ffff8800b6bf6000 ffff880c1c988000 ffff880619903850 ffff88061a003b68 ffffffffa0056ce1 ffff88061a003b48 0000000013d6e6f8 ffff88000241ca80 Call Trace: [] ata_sas_queuecmd+0xa1/0x430 [] sas_queuecommand+0x191/0x220 [libsas] [] scsi_dispatch_cmd+0x10e/0x300 [] scsi_request_fn+0x2f5/0x550 [] __blk_run_queue+0x33/0x40 [] queue_unplugged+0x2a/0x90 [] blk_flush_plug_list+0x1b4/0x210 [] blk_finish_plug+0x14/0x50 [] __do_page_cache_readahead+0x198/0x1f0 [] force_page_cache_readahead+0x31/0x50 [] page_cache_sync_readahead+0x3e/0x50 [] generic_file_read_iter+0x496/0x5a0 [] blkdev_read_iter+0x37/0x40 [] new_sync_read+0x7e/0xb0 [] vfs_read+0x94/0x170 [] SyS_read+0x46/0xb0 [] ? SyS_lseek+0x91/0xb0 [] system_call_fastpath+0x16/0x1b Code: 00 00 00 88 50 29 83 7f 08 01 19 d2 83 e2 f0 83 ea 50 88 50 34 c6 81 1d 02 00 00 40 c6 81 17 02 00 00 00 5d c3 66 0f 1f 44 00 00 <89> 14 25 58 00 00 00 Fix it by introducing ata_host->n_tags which is initialized to ATA_MAX_QUEUE - 1 in ata_host_init() for SAS controllers and set to scsi_host_template->can_queue in ata_host_register() for !SAS ones. As SAS hosts are never registered, this will give them the same ATA_MAX_QUEUE - 1 as before. Note that we can't use scsi_host->can_queue directly for SAS hosts anyway as they can go higher than the libata maximum. Signed-off-by: Tejun Heo Reported-by: Mike Qiu Reported-by: Jesse Brandeburg Reported-by: Peter Hurley Reported-by: Peter Zijlstra Tested-by: Alexey Kardashevskiy Fixes: 1871ee134b73 ("libata: support the ata host which implements a queue depth less than 32") Cc: Kevin Hao Cc: Dan Williams Signed-off-by: Greg Kroah-Hartman

ring-buffer: Check if buffer exists before polling

2014-07-17T23:21:06+00:00

commit 8b8b36834d0fff67fc8668093f4312dd04dcf21d upstream. The per_cpu buffers are created one per possible CPU. But these do not mean that those CPUs are online, nor do they even exist. With the addition of the ring buffer polling, it assumes that the caller polls on an existing buffer. But this is not the case if the user reads trace_pipe from a CPU that does not exist, and this causes the kernel to crash. Simple fix is to check the cpu against buffer bitmask against to see if the buffer was allocated or not and return -ENODEV if it is not. More updates were done to pass the -ENODEV back up to userspace. Link: http://lkml.kernel.org/r/5393DB61.6060707@oracle.com Reported-by: Sasha Levin Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman