24 Sep, 2009
1 commit
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For this system call user space passes a signed long length parameter,
while the kernel side takes an unsigned long parameter and converts it
later to signed long again.This has led to bugs in compat wrappers see e.g. dd90bbd5 "powerpc: Add
compat_sys_truncate". The s390 compat wrapper for this functions is
broken as well since it also performs zero extension instead of sign
extension for the length parameter.In addition if hpa comes up with an automated way of generating
compat wrappers it would generate a wrong one here.So change the length parameter from unsigned long to long.
Cc: "H. Peter Anvin"
Cc: Al Viro
Cc: Christoph Hellwig
Signed-off-by: Heiko Carstens
Signed-off-by: Linus Torvalds
02 Sep, 2009
1 commit
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Add a config option (CONFIG_DEBUG_CREDENTIALS) to turn on some debug checking
for credential management. The additional code keeps track of the number of
pointers from task_structs to any given cred struct, and checks to see that
this number never exceeds the usage count of the cred struct (which includes
all references, not just those from task_structs).Furthermore, if SELinux is enabled, the code also checks that the security
pointer in the cred struct is never seen to be invalid.This attempts to catch the bug whereby inode_has_perm() faults in an nfsd
kernel thread on seeing cred->security be a NULL pointer (it appears that the
credential struct has been previously released):http://www.kerneloops.org/oops.php?number=252883
Signed-off-by: David Howells
Signed-off-by: James Morris
21 Aug, 2009
1 commit
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When suid is set and the non-owner user has write permission, any writing
into this file should be allowed and suid should be removed after that.However, current kernel only allows writing without truncations, when we
do truncations on that file, we get EPERM. This is a bug.Steps to reproduce this bug:
% ls -l rootdir/file1
-rwsrwsrwx 1 root root 3 Jun 25 15:42 rootdir/file1
% echo h > rootdir/file1
zsh: operation not permitted: rootdir/file1
% ls -l rootdir/file1
-rwsrwsrwx 1 root root 3 Jun 25 15:42 rootdir/file1
% echo h >> rootdir/file1
% ls -l rootdir/file1
-rwxrwxrwx 1 root root 5 Jun 25 16:34 rootdir/file1Signed-off-by: WANG Cong
Cc: Eric Sandeen
Acked-by: Eric Paris
Cc: Eugene Teo
Cc: Al Viro
Cc: OGAWA Hirofumi
Cc: Christoph Hellwig
Cc: Stephen Smalley
Signed-off-by: Andrew Morton
Signed-off-by: James Morris
24 Jun, 2009
1 commit
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This patch adds ioctls to vfs for compatibility with legacy XFS
pre-allocation ioctls (XFS_IOC_*RESVP*). The implementation
effectively invokes sys_fallocate for the new ioctls.
Also handles the compat_ioctl case.
Note: These legacy ioctls are also implemented by OCFS2.[AV: folded fixes from hch]
Signed-off-by: Ankit Jain
Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
12 Jun, 2009
1 commit
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This patch speeds up lmbench lat_mmap test by about another 2% after the
first patch.Before:
avg = 462.286
std = 5.46106After:
avg = 453.12
std = 9.58257(50 runs of each, stddev gives a reasonable confidence)
It does this by introducing mnt_clone_write, which avoids some heavyweight
operations of mnt_want_write if called on a vfsmount which we know already
has a write count; and mnt_want_write_file, which can call mnt_clone_write
if the file is open for write.After these two patches, mnt_want_write and mnt_drop_write go from 7% on
the profile down to 1.3% (including mnt_clone_write).[AV: mnt_want_write_file() should take file alone and derive mnt from it;
not only all callers have that form, but that's the only mnt about which
we know that it's already held for write if file is opened for write]Cc: Dave Hansen
Signed-off-by: Nick Piggin
Signed-off-by: Al Viro
09 May, 2009
1 commit
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... and make path_lookup_open() static
Signed-off-by: Al Viro
01 Apr, 2009
1 commit
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Don't pull it in sched.h; very few files actually need it and those
can include directly. sched.h itself only needs forward declaration
of struct fs_struct;Signed-off-by: Al Viro
26 Mar, 2009
1 commit
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Use lowercase names of quota functions instead of old uppercase ones.
Signed-off-by: Jan Kara
CC: Alexander Viro
14 Jan, 2009
9 commits
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Signed-off-by: Heiko Carstens
-
Signed-off-by: Heiko Carstens
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Signed-off-by: Heiko Carstens
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Signed-off-by: Heiko Carstens
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Signed-off-by: Heiko Carstens
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Signed-off-by: Heiko Carstens
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Signed-off-by: Heiko Carstens
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Signed-off-by: Heiko Carstens
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System calls with an unsigned long long argument can't be converted with
the standard wrappers since that would include a cast to long, which in
turn means that we would lose the upper 32 bit on 32 bit architectures.
Also semctl can't use the standard wrapper since it has a 'union'
parameter.So we handle them as special case and add some extra wrappers instead.
Signed-off-by: Heiko Carstens
06 Jan, 2009
1 commit
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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
01 Jan, 2009
1 commit
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Add new LSM hooks for path-based checks. Call them on directory-modifying
operations at the points where we still know the vfsmount involved.Signed-off-by: Kentaro Takeda
Signed-off-by: Tetsuo Handa
Signed-off-by: Toshiharu Harada
Signed-off-by: Al Viro
14 Nov, 2008
4 commits
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Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).This patch and the preceding patches have been tested with the LTP SELinux
testsuite.This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()Changed. These now take cred pointers rather than task pointers to
refer to the security context.(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.Signed-off-by: David Howells
Acked-by: James Morris
Signed-off-by: James Morris -
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
Acked-by: James Morris
Signed-off-by: James Morris -
Separate the task security context from task_struct. At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.With comment fixes Signed-off-by: Marc Dionne
Signed-off-by: David Howells
Acked-by: James Morris
Acked-by: Serge Hallyn
Signed-off-by: James Morris -
Take away the ability for sys_capset() to affect processes other than current.
This means that current will not need to lock its own credentials when reading
them against interference by other processes.This has effectively been the case for a while anyway, since:
(1) Without LSM enabled, sys_capset() is disallowed.
(2) With file-based capabilities, sys_capset() is neutered.
Signed-off-by: David Howells
Acked-by: Serge Hallyn
Acked-by: Andrew G. Morgan
Acked-by: James Morris
Signed-off-by: James Morris
21 Oct, 2008
1 commit
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Signed-off-by: Al Viro
14 Oct, 2008
1 commit
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We now have the infrastructure to sort this out but rather than teaching
the syscall tty lock rules we move the hard work into a tty helperSigned-off-by: Alan Cox
Signed-off-by: Linus Torvalds
01 Aug, 2008
1 commit
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New primitive: alloc_fd(start, flags). get_unused_fd() and
get_unused_fd_flags() become wrappers on top of it.Signed-off-by: Al Viro
27 Jul, 2008
9 commits
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* dup2() should return -EBADF on exceeded sysctl_nr_open
* dup() should *not* return -EINVAL even if you have rlimit set to 0;
it should get -EMFILE instead.Check for orig_start exceeding rlimit taken to sys_fcntl().
Failing expand_files() in dup{2,3}() now gets -EMFILE remapped to -EBADF.
Consequently, remaining checks for rlimit are taken to expand_files().Signed-off-by: Al Viro
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* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
user_path_at(dfd, pathname, flags, &path)
user_path(pathname, &path)
user_lpath(pathname, &path)
user_path_dir(pathname, &path) (fail if not a directory)
The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.Signed-off-by: Al Viro
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Almost all users __user_walk_fd() and friends care only about struct path.
Get rid of the few that do not.Signed-off-by: Al Viro
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Signed-off-by: Al Viro
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Move the immutable and append-only checks from chmod, chown and utimes
into notify_change(). Checks for immutable and append-only files are
always performed by the VFS and not by the filesystem (see
permission() and may_...() in namei.c), so these belong in
notify_change(), and not in inode_change_ok().This should be completely equivalent.
CC: Ulrich Drepper
CC: Michael Kerrisk
Signed-off-by: Miklos Szeredi
Signed-off-by: Al Viro -
* MAY_CHDIR is redundant - it's an equivalent of MAY_ACCESS
* MAY_ACCESS on fuse should affect only the last step of pathname resolution
* fchdir() and chroot() should pass MAY_ACCESS, for the same reason why
chdir() needs that.
* now that we pass MAY_ACCESS explicitly in all cases, LOOKUP_ACCESS can be
removed; it has no business being in nameidata.Signed-off-by: Al Viro
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long overdue...
Signed-off-by: Al Viro
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... so we ought to pass MAY_CHDIR to vfs_permission() instead of having
it triggered on every step of preceding pathname resolution. LOOKUP_CHDIR
is killed by that.Signed-off-by: Al Viro
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vfs_permission(MAY_WRITE) already checked for the inode being
immutable, so no need to repeat it.Signed-off-by: Miklos Szeredi
Acked-by: Christoph Hellwig
25 Jul, 2008
1 commit
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Adds a check for an overflow in the filesystem size so if someone is
checking with statfs() on a 16G blocksize hugetlbfs in a 32bit binary that
it will report back EOVERFLOW instead of a size of 0.Acked-by: Nishanth Aravamudan
Signed-off-by: Jon Tollefson
Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Jul, 2008
1 commit
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This commit includes a bugfix for the fragile setuid fixup code in the
case that filesystem capabilities are supported (in access()). The effect
of this fix is gated on filesystem capability support because changing
securebits is only supported when filesystem capabilities support is
configured.)[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andrew G. Morgan
Acked-by: Serge Hallyn
Acked-by: David Howells
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 May, 2008
1 commit
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Initial splitoff of the low-level stuff; taken to fdtable.h
Signed-off-by: Al Viro
28 Apr, 2008
1 commit
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Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for
the user mappings.This requires the get_xip_page API to be changed to an address based one.
Improve the API layering a little bit too, while we're here.This is required in order to support XIP filesystems on memory that isn't
backed with struct page (but memory with struct page is still supported too).Signed-off-by: Nick Piggin
Acked-by: Carsten Otte
Cc: Jared Hulbert
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Apr, 2008
1 commit
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There have been a few oopses caused by 'struct file's with NULL f_vfsmnts.
There was also a set of potentially missed mnt_want_write()s from
dentry_open() calls.This patch provides a very simple debugging framework to catch these kinds of
bugs. It will WARN_ON() them, but should stop us from having any oopses or
mnt_writer count imbalances.I'm quite convinced that this is a good thing because it found bugs in the
stuff I was working on as soon as I wrote it.[hch: made it conditional on a debug option.
But it's still a little bit too ugly][hch: merged forced remount r/o fix from Dave and akpm's fix for the fix]
Signed-off-by: Dave Hansen
Acked-by: Al Viro
Signed-off-by: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro
