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- 10 Jun, 2013 5 commits
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Oleg Nesterov authored
commit 1cc684ab upstream As Tetsuo Handa pointed out, request_module() can stress the system while the oom-killed caller sleeps in TASK_UNINTERRUPTIBLE. The task T uses "almost all" memory, then it does something which triggers request_module(). Say, it can simply call sys_socket(). This in turn needs more memory and leads to OOM. oom-killer correctly chooses T and kills it, but this can't help because it sleeps in TASK_UNINTERRUPTIBLE and after that oom-killer becomes "disabled" by the TIF_MEMDIE task T. Make __request_module() killable. The only necessary change is that call_modprobe() should kmalloc argv and module_name, they can't live in the stack if we use UMH_KILLABLE. This memory is freed via call_usermodehelper_freeinfo()->cleanup. Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [dannf, bwh: backported to Debian's 2.6.32] Signed-off-by: Willy Tarreau <w@1wt.eu>
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Oleg Nesterov authored
commit 3e63a93b upstream No functional changes. Move the call_usermodehelper code from __request_module() into the new simple helper, call_modprobe(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [dannf: backported to Debian's 2.6.32] Signed-off-by: Willy Tarreau <w@1wt.eu>
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Oleg Nesterov authored
commit 5b9bd473 upstream Minor cleanup. ____call_usermodehelper() can simply return, no need to call do_exit() explicitely. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [dannf: adjusted to apply to Debian's 2.6.32] Signed-off-by: Willy Tarreau <w@1wt.eu>
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Oleg Nesterov authored
commit d0bd587a upstream Implement UMH_KILLABLE, should be used along with UMH_WAIT_EXEC/PROC. The caller must ensure that subprocess_info->path/etc can not go away until call_usermodehelper_freeinfo(). call_usermodehelper_exec(UMH_KILLABLE) does wait_for_completion_killable. If it fails, it uses xchg(&sub_info->complete, NULL) to serialize with umh_complete() which does the same xhcg() to access sub_info->complete. If call_usermodehelper_exec wins, it can safely return. umh_complete() should get NULL and call call_usermodehelper_freeinfo(). Otherwise we know that umh_complete() was already called, in this case call_usermodehelper_exec() falls back to wait_for_completion() which should succeed "very soon". Note: UMH_NO_WAIT == -1 but it obviously should not be used with UMH_KILLABLE. We delay the neccessary cleanup to simplify the back porting. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [dannf: backported to Debian's 2.6.32] Signed-off-by: Willy Tarreau <w@1wt.eu>
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Oleg Nesterov authored
commit b3449922 upstream Preparation. Add the new trivial helper, umh_complete(). Currently it simply does complete(sub_info->complete). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [dannf: Adjusted to apply to Debian's 2.6.32] Signed-off-by: Willy Tarreau <w@1wt.eu>
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- 04 Mar, 2012 2 commits
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Srivatsa S. Bhat authored
[ Upstream commit b298d289 ] Commit a144c6a6 (PM: Print a warning if firmware is requested when tasks are frozen) introduced usermodehelper_is_disabled() to warn and exit immediately if firmware is requested when usermodehelpers are disabled. However, it is racy. Consider the following scenario, currently used in drivers/base/firmware_class.c: ... if (usermodehelper_is_disabled()) goto out; /* Do actual work */ ... out: return err; Nothing prevents someone from disabling usermodehelpers just after the check in the 'if' condition, which means that it is quite possible to try doing the "actual work" with usermodehelpers disabled, leading to undesirable consequences. In particular, this race condition in _request_firmware() causes task freezing failures whenever suspend/hibernation is in progress because, it wrongly waits to get the firmware/microcode image from userspace when actually the usermodehelpers are disabled or userspace has been frozen. Some of the example scenarios that cause freezing failures due to this race are those that depend on userspace via request_firmware(), such as x86 microcode module initialization and microcode image reload. Previous discussions about this issue can be found at: http://thread.gmane.org/gmane.linux.kernel/1198291/focus=1200591 This patch adds proper synchronization to fix this issue. It is to be noted that this patchset fixes the freezing failures but doesn't remove the warnings. IOW, it does not attempt to add explicit synchronization to x86 microcode driver to avoid requesting microcode image at inopportune moments. Because, the warnings were introduced to highlight such cases, in the first place. And we need not silence the warnings, since we take care of the *real* problem (freezing failure) and hence, after that, the warnings are pretty harmless anyway. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Rafael J. Wysocki authored
[ Upstream commit a144c6a6 ] Some drivers erroneously use request_firmware() from their ->resume() (or ->thaw(), or ->restore()) callbacks, which is not going to work unless the firmware has been built in. This causes system resume to stall until the firmware-loading timeout expires, which makes users think that the resume has failed and reboot their machines unnecessarily. For this reason, make _request_firmware() print a warning and return immediately with error code if it has been called when tasks are frozen and it's impossible to start any new usermode helpers. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Reviewed-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 07 Nov, 2011 1 commit
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Jiri Kosina authored
commit 37252db6 upstream. Due to post-increment in condition of kmod_loop_msg in __request_module(), the system log can be spammed by much more than 5 instances of the 'runaway loop' message if the number of events triggering it makes the kmod_loop_msg to overflow. Fix that by making sure we never increment it past the threshold. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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- 24 Sep, 2009 1 commit
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Sebastian Andrzej Siewior authored
This reverts commit c02e3f36 ("kmod: fix race in usermodehelper code") The patch is wrong. UMH_WAIT_EXEC is called with VFORK what ensures that the child finishes prior returing back to the parent. No race. In fact, the patch makes it even worse because it does the thing it claims not do: - It calls ->complete() on UMH_WAIT_EXEC - the complete() callback may de-allocated subinfo as seen in the following call chain: [<c009f904>] (__link_path_walk+0x20/0xeb4) from [<c00a094c>] (path_walk+0x48/0x94) [<c00a094c>] (path_walk+0x48/0x94) from [<c00a0a34>] (do_path_lookup+0x24/0x4c) [<c00a0a34>] (do_path_lookup+0x24/0x4c) from [<c00a158c>] (do_filp_open+0xa4/0x83c) [<c00a158c>] (do_filp_open+0xa4/0x83c) from [<c009ba90>] (open_exec+0x24/0xe0) [<c009ba90>] (open_exec+0x24/0xe0) from [<c009bfa8>] (do_execve+0x7c/0x2e4) [<c009bfa8>] (do_execve+0x7c/0x2e4) from [<c0026a80>] (kernel_execve+0x34/0x80) [<c0026a80>] (kernel_execve+0x34/0x80) from [<c004b514>] (____call_usermodehelper+0x130/0x148) [<c004b514>] (____call_usermodehelper+0x130/0x148) from [<c0024858>] (kernel_thread_exit+0x0/0x8) and the path pointer was NULL. Good that ARM's kernel_execve() doesn't check the pointer for NULL or else I wouldn't notice it. The only race there might be is with UMH_NO_WAIT but it is too late for me to investigate it now. UMH_WAIT_PROC could probably also use VFORK and we could save one exec. So the only race I see is with UMH_NO_WAIT and recent scheduler changes where the child does not always run first might have trigger here something but as I said, it is late.... Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 23 Sep, 2009 1 commit
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Neil Horman authored
The user mode helper code has a race in it. call_usermodehelper_exec() takes an allocated subprocess_info structure, which it passes to a workqueue, and then passes it to a kernel thread which it creates, after which it calls complete to signal to the caller of call_usermodehelper_exec() that it can free the subprocess_info struct. But since we use that structure in the created thread, we can't call complete from __call_usermodehelper(), which is where we create the kernel thread. We need to call complete() from within the kernel thread and then not use subprocess_info afterward in the case of UMH_WAIT_EXEC. Tested successfully by me. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 02 Sep, 2009 1 commit
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David Howells authored
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=252883Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
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- 17 Aug, 2009 1 commit
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Li Zefan authored
Add trace points to trace module_load, module_free, module_get, module_put and module_request, and use trace_event facility to get the trace output. Here's the sample output: TASK-PID CPU# TIMESTAMP FUNCTION | | | | | <...>-42 [000] 1.758380: module_request: fb0 wait=1 call_site=fb_open ... <...>-60 [000] 3.269403: module_load: scsi_wait_scan <...>-60 [000] 3.269432: module_put: scsi_wait_scan call_site=sys_init_module refcnt=0 <...>-61 [001] 3.273168: module_free: scsi_wait_scan ... <...>-1021 [000] 13.836081: module_load: sunrpc <...>-1021 [000] 13.840589: module_put: sunrpc call_site=sys_init_module refcnt=-1 <...>-1027 [000] 13.848098: module_get: sunrpc call_site=try_module_get refcnt=0 <...>-1027 [000] 13.848308: module_get: sunrpc call_site=get_filesystem refcnt=1 <...>-1027 [000] 13.848692: module_put: sunrpc call_site=put_filesystem refcnt=0 ... modprobe-2587 [001] 1088.437213: module_load: trace_events_sample F modprobe-2587 [001] 1088.437786: module_put: trace_events_sample call_site=sys_init_module refcnt=0 Note: - the taints flag can be 'F', 'C' and/or 'P' if mod->taints != 0 - the module refcnt is percpu, so it can be negative in a specific cpu Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> LKML-Reference: <4A891B3C.5030608@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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- 14 Aug, 2009 1 commit
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Eric Paris authored
Calling request_module() will trigger a userspace upcall which will load a new module into the kernel. This can be a dangerous event if the process able to trigger request_module() is able to control either the modprobe binary or the module binary. This patch adds a new security hook to request_module() which can be used by an LSM to control a processes ability to call request_module(). Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
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- 08 Jul, 2009 1 commit
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Alexey Dobriyan authored
Fix various silly problems wrt mnt_namespace.h: - exit_mnt_ns() isn't used, remove it - done that, sched.h and nsproxy.h inclusions aren't needed - mount.h inclusion was need for vfsmount_lock, but no longer - remove mnt_namespace.h inclusion from files which don't use anything from mnt_namespace.h Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 26 May, 2009 1 commit
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Tetsuo Handa authored
call_usermodehelper_setup() forgot to kfree(sub_info) when prepare_usermodehelper_creds() failed. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 31 Mar, 2009 1 commit
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Arjan van de Ven authored
There seems to be a common pattern in the kernel where drivers want to call request_module() from inside a module_init() function. Currently this would deadlock. As a result, several drivers go through hoops like scheduling things via kevent, or creating custom work queues (because kevent can deadlock on them). This patch changes this to use a request_module_nowait() function macro instead, which just fires the modprobe off but doesn't wait for it, and thus avoids the original deadlock entirely. On my laptop this already results in one less kernel thread running.. (Includes Jiri's patch to use enum umh_wait) Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (bool-ified) Cc: Jiri Slaby <jirislaby@gmail.com>
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- 30 Mar, 2009 1 commit
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Rusty Russell authored
Impact: cleanup (Thanks to Al Viro for reminding me of this, via Ingo) CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so: #define CPU_MASK_ALL (cpumask_t) { { ... } } Taking the address of such a temporary is questionable at best, unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added CPU_MASK_ALL_PTR: #define CPU_MASK_ALL_PTR (&CPU_MASK_ALL) Which formalizes this practice. One day gcc could bite us over this usage (though we seem to have gotten away with it so far). So replace everywhere which used &CPU_MASK_ALL or CPU_MASK_ALL_PTR with the modern "cpu_all_mask" (a real const struct cpumask *). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Ingo Molnar <mingo@elte.hu> Reported-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Mike Travis <travis@sgi.com>
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- 06 Jan, 2009 1 commit
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Randy Dunlap authored
Fix varargs kernel-doc format in kmod.c: Use @... instead of @varargs. Warning(kernel/kmod.c:67): Excess function parameter or struct member 'varargs' description in 'request_module' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 13 Nov, 2008 2 commits
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David Howells authored
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 <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: James Morris <jmorris@namei.org>
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David Howells authored
Alter the use of the key instantiation and negation functions' link-to-keyring arguments. Currently this specifies a keyring in the target process to link the key into, creating the keyring if it doesn't exist. This, however, can be a problem for copy-on-write credentials as it means that the instantiating process can alter the credentials of the requesting process. This patch alters the behaviour such that: (1) If keyctl_instantiate_key() or keyctl_negate_key() are given a specific keyring by ID (ringid >= 0), then that keyring will be used. (2) If keyctl_instantiate_key() or keyctl_negate_key() are given one of the special constants that refer to the requesting process's keyrings (KEY_SPEC_*_KEYRING, all <= 0), then: (a) If sys_request_key() was given a keyring to use (destringid) then the key will be attached to that keyring. (b) If sys_request_key() was given a NULL keyring, then the key being instantiated will be attached to the default keyring as set by keyctl_set_reqkey_keyring(). (3) No extra link will be made. Decision point (1) follows current behaviour, and allows those instantiators who've searched for a specifically named keyring in the requestor's keyring so as to partition the keys by type to still have their named keyrings. Decision point (2) allows the requestor to make sure that the key or keys that get produced by request_key() go where they want, whilst allowing the instantiator to request that the key is retained. This is mainly useful for situations where the instantiator makes a secondary request, the key for which should be retained by the initial requestor: +-----------+ +--------------+ +--------------+ | | | | | | | Requestor |------->| Instantiator |------->| Instantiator | | | | | | | +-----------+ +--------------+ +--------------+ request_key() request_key() This might be useful, for example, in Kerberos, where the requestor requests a ticket, and then the ticket instantiator requests the TGT, which someone else then has to go and fetch. The TGT, however, should be retained in the keyrings of the requestor, not the first instantiator. To make this explict an extra special keyring constant is also added. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: James Morris <jmorris@namei.org>
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- 16 Oct, 2008 2 commits
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Rafael J. Wysocki authored
We currently use a PM notifier to disable user mode helpers before suspend and hibernation and to re-enable them during resume. However, this is not an ideal solution, because if any drivers want to upload firmware into memory before suspend, they have to use a PM notifier for this purpose and there is no guarantee that the ordering of PM notifiers will be as expected (ie. the notifier that disables user mode helpers has to be run after the driver's notifier used for uploading the firmware). For this reason, it seems better to move the disabling and enabling of user mode helpers to separate functions that will be called by the PM core as necessary. [akpm@linux-foundation.org: remove unneeded ifdefs] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Alan Stern <stern@rowland.harvard.edu> Acked-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rusty Russell authored
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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- 25 Jul, 2008 1 commit
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KOSAKI Motohiro authored
Presently call_usermodehelper_setup() uses GFP_ATOMIC. but it can return NULL _very_ easily. GFP_ATOMIC is needed only when we can't sleep. and, GFP_KERNEL is robust and better. thus, I add gfp_mask argument to call_usermodehelper_setup(). So, its callers pass the gfp_t as below: call_usermodehelper() and call_usermodehelper_keys(): depend on 'wait' argument. call_usermodehelper_pipe(): always GFP_KERNEL because always run under process context. orderly_poweroff(): pass to GFP_ATOMIC because may run under interrupt context. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: "Paul Menage" <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 24 Jul, 2008 1 commit
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Ulrich Drepper authored
This patch adds O_NONBLOCK support to pipe2. It is minimally more involved than the patches for eventfd et.al but still trivial. The interfaces of the create_write_pipe and create_read_pipe helper functions were changed and the one other caller as well. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <fcntl.h> #include <stdio.h> #include <unistd.h> #include <sys/syscall.h> #ifndef __NR_pipe2 # ifdef __x86_64__ # define __NR_pipe2 293 # elif defined __i386__ # define __NR_pipe2 331 # else # error "need __NR_pipe2" # endif #endif int main (void) { int fds[2]; if (syscall (__NR_pipe2, fds, 0) == -1) { puts ("pipe2(0) failed"); return 1; } for (int i = 0; i < 2; ++i) { int fl = fcntl (fds[i], F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if (fl & O_NONBLOCK) { printf ("pipe2(0) set non-blocking mode for fds[%d]\n", i); return 1; } close (fds[i]); } if (syscall (__NR_pipe2, fds, O_NONBLOCK) == -1) { puts ("pipe2(O_NONBLOCK) failed"); return 1; } for (int i = 0; i < 2; ++i) { int fl = fcntl (fds[i], F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if ((fl & O_NONBLOCK) == 0) { printf ("pipe2(O_NONBLOCK) does not set non-blocking mode for fds[%d]\n", i); return 1; } close (fds[i]); } puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 22 Jul, 2008 1 commit
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Johannes Berg authored
Always compile request_module when the kernel allows modules. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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- 01 May, 2008 1 commit
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Al Viro authored
Initial splitoff of the low-level stuff; taken to fdtable.h Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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- 19 Apr, 2008 1 commit
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Mike Travis authored
* Use new set_cpus_allowed_ptr() function added by previous patch, which instead of passing the "newly allowed cpus" cpumask_t arg by value, pass it by pointer: -int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) +int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask) * Modify CPU_MASK_ALL Depends on: [sched-devel]: sched: add new set_cpus_allowed_ptr function Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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- 15 Feb, 2008 1 commit
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Jan Blunck authored
This test seems to be unnecessary since we always have rootfs mounted before calling a usermodehelper. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Jan Blunck <jblunck@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 17 Jan, 2008 1 commit
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Nigel Cunningham authored
call_usermodehelper_exec() has an exit path that can leave the helper_lock() call at the top of the routine unbalanced. The attached patch fixes this issue. Signed-off-by: Nigel Cunningham <nigel@tuxonice.net> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 12 Sep, 2007 1 commit
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Michael Ellerman authored
The semantics of call_usermodehelper_pipe() used to be that it would fork the helper, and wait for the kernel thread to be started. This was implemented by setting sub_info.wait to 0 (implicitly), and doing a wait_for_completion(). As part of the cleanup done in 0ab4dc92, call_usermodehelper_pipe() was changed to pass 1 as the value for wait to call_usermodehelper_exec(). This is equivalent to setting sub_info.wait to 1, which is a change from the previous behaviour. Using 1 instead of 0 causes __call_usermodehelper() to start the kernel thread running wait_for_helper(), rather than directly calling ____call_usermodehelper(). The end result is that the calling kernel code blocks until the user mode helper finishes. As the helper is expecting input on stdin, and now no one is writing anything, everything locks up (observed in do_coredump). The fix is to change the 1 to UMH_WAIT_EXEC (aka 0), indicating that we want to wait for the kernel thread to be started, but not for the helper to finish. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 26 Jul, 2007 1 commit
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Randy Dunlap authored
Fix kmod.c: Warning(linux-2.6.23-rc1//kernel/kmod.c:364): No description found for parameter 'envp' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 19 Jul, 2007 2 commits
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Rafael J. Wysocki authored
At present, if a user mode helper is running while usermodehelper_pm_callback() is executed, the helper may be frozen and the completion in call_usermodehelper_exec() won't be completed until user space processes are thawed. As a result, the freezing of kernel threads may fail, which is not desirable. Prevent this from happening by introducing a counter of running user mode helpers and allowing usermodehelper_pm_callback() to succeed for action = PM_HIBERNATION_PREPARE or action = PM_SUSPEND_PREPARE only if there are no helpers running. [Namely, usermodehelper_pm_callback() waits for at most RUNNING_HELPERS_TIMEOUT for the number of running helpers to become zero and fails if that doesn't happen.] Special thanks to Uli Luckas <u.luckas@road.de>, Pavel Machek <pavel@ucw.cz> and Oleg Nesterov <oleg@tv-sign.ru> for reviewing the previous versions of this patch and for very useful comments. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Uli Luckas <u.luckas@road.de> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rafael J. Wysocki authored
Use a hibernation and suspend notifier to disable the user mode helper before a hibernation/suspend and enable it after the operation. [akpm@linux-foundation.org: build fix] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 18 Jul, 2007 2 commits
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Jeremy Fitzhardinge authored
Rather than using a tri-state integer for the wait flag in call_usermodehelper_exec, define a proper enum, and use that. I've preserved the integer values so that any callers I've missed should still work OK. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Andi Kleen <ak@suse.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com>
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Jeremy Fitzhardinge authored
Rather than having hundreds of variations of call_usermodehelper for various pieces of usermode state which could be set up, split the info allocation and initialization from the actual process execution. This means the general pattern becomes: info = call_usermodehelper_setup(path, argv, envp); /* basic state */ call_usermodehelper_<SET EXTRA STATE>(info, stuff...); /* extra state */ call_usermodehelper_exec(info, wait); /* run process and free info */ This patch introduces wrappers for all the existing calling styles for call_usermodehelper_*, but folds their implementations into one. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: David Howells <dhowells@redhat.com> Cc: Bj?rn Steinbrink <B.Steinbrink@gmx.de> Cc: Randy Dunlap <randy.dunlap@oracle.com>
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- 09 May, 2007 2 commits
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Oleg Nesterov authored
allow_signal(SIGCHLD) does all necessary job, no need to call do_sigaction() prior to. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Oleg Nesterov authored
____call_usermodehelper() has no reason for flush_signals(). It is a fresh forked process which is going to exec a user-space application or exit on failure. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 08 May, 2007 2 commits
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Jan Engelhardt authored
Fix kevent's childs priority greediness. Such tasks were always scheduled at nice level -5 and, at that time, udev stole us the CPU time with -5. Already posted at http://lkml.org/lkml/2005/1/10/85 [akpm@linux-foundation.org: add comment] Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Randy Dunlap authored
Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 23 Feb, 2007 1 commit
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Greg Kroah-Hartman authored
This reverts commit c353c3fb. It turns out that we end up with a loop trying to load the unix module and calling netfilter to do that. Will redo the patch later to not have this loop. Acked-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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