user/sven/linux.git/include/linux, branch v3.16.3

mnt: Correct permission checks in do_remount

2014-09-17T16:22:12Z

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

2014-09-17T16:22:12Z

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

fanotify: fix double free of pending permission events

2014-09-17T16:21:53Z

commit 5838d4442bd5971687b72221736222637e03140d upstream. Commit 85816794240b ("fanotify: Fix use after free for permission events") introduced a double free issue for permission events which are pending in group's notification queue while group is being destroyed. These events are freed from fanotify_handle_event() but they are not removed from groups notification queue and thus they get freed again from fsnotify_flush_notify(). Fix the problem by removing permission events from notification queue before freeing them if we skip processing access response. Also expand comments in fanotify_release() to explain group shutdown in detail. Fixes: 85816794240b9659e66e4d9b0df7c6e814e5f603 Signed-off-by: Jan Kara Reported-by: Douglas Leeder Tested-by: Douglas Leeder Reported-by: Heinrich Schuchard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

CAPABILITIES: remove undefined caps from all processes

2014-09-17T16:21:53Z

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

2014-09-17T16:21:52Z

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

2014-09-05T23:36:42Z

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

2014-09-05T23:36:39Z

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

kexec: export free_huge_page to VMCOREINFO

2014-07-31T00:16:13Z

PG_head_mask was added into VMCOREINFO to filter huge pages in b3acc56bfe1 ("kexec: save PG_head_mask in VMCOREINFO"), but makedumpfile still need another symbol to filter *hugetlbfs* pages. If a user hope to filter user pages, makedumpfile tries to exclude them by checking the condition whether the page is anonymous, but hugetlbfs pages aren't anonymous while they also be user pages. We know it's possible to detect them in the same way as PageHuge(), so we need the start address of free_huge_page(): int PageHuge(struct page *page) { if (!PageCompound(page)) return 0; page = compound_head(page); return get_compound_page_dtor(page) == free_huge_page; } For that reason, this patch changes free_huge_page() into public to export it to VMCOREINFO. Signed-off-by: Atsushi Kumagai Acked-by: Baoquan He Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

of: Add memory limiting function for flattened devicetrees

2014-07-30T03:26:45Z

Buggy bootloaders may pass bogus memory entries in the devicetree. Add of_fdt_limit_memory to add an upper bound on the number of entries that can be present in the devicetree. Signed-off-by: Laura Abbott Tested-by: Andreas Färber Signed-off-by: Grant Likely

of: Split early_init_dt_scan into two parts

2014-07-30T03:26:37Z

Currently, early_init_dt_scan validates the header, sets the boot params, and scans for chosen/memory all in one function. Split this up into two separate functions (validation/setting boot params in one, scanning in another) to allow for additional setup between boot params and scanning the memory. Signed-off-by: Laura Abbott Tested-by: Andreas Färber [glikely: s/early_init_dt_scan_all/early_init_dt_scan_nodes/] Signed-off-by: Grant Likely