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2008-07-14Security: split proc ptrace checking into read vs. attachStephen Smalley
Enable security modules to distinguish reading of process state via proc from full ptrace access by renaming ptrace_may_attach to ptrace_may_access and adding a mode argument indicating whether only read access or full attach access is requested. This allows security modules to permit access to reading process state without granting full ptrace access. The base DAC/capability checking remains unchanged. Read access to /proc/pid/mem continues to apply a full ptrace attach check since check_mem_permission() already requires the current task to already be ptracing the target. The other ptrace checks within proc for elements like environ, maps, and fds are changed to pass the read mode instead of attach. In the SELinux case, we model such reading of process state as a reading of a proc file labeled with the target process' label. This enables SELinux policy to permit such reading of process state without permitting control or manipulation of the target process, as there are a number of cases where programs probe for such information via proc but do not need to be able to control the target (e.g. procps, lsof, PolicyKit, ConsoleKit). At present we have to choose between allowing full ptrace in policy (more permissive than required/desired) or breaking functionality (or in some cases just silencing the denials via dontaudit rules but this can hide genuine attacks). This version of the patch incorporates comments from Casey Schaufler (change/replace existing ptrace_may_attach interface, pass access mode), and Chris Wright (provide greater consistency in the checking). Note that like their predecessors __ptrace_may_attach and ptrace_may_attach, the __ptrace_may_access and ptrace_may_access interfaces use different return value conventions from each other (0 or -errno vs. 1 or 0). I retained this difference to avoid any changes to the caller logic but made the difference clearer by changing the latter interface to return a bool rather than an int and by adding a comment about it to ptrace.h for any future callers. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: James Morris <jmorris@namei.org>
2008-05-01make generic sys_ptrace unconditionalChristoph Hellwig
With s390 the last arch switched to the generic sys_ptrace yesterday so we can now kill the ifdef around it to enforce every new port it using it instead of introducing new weirdo versions. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30ptrace: permit ptracing of /sbin/initOleg Nesterov
Afaics, currently there are no kernel problems with ptracing init, it can't lose SIGNAL_UNKILLABLE flag and be killed/stopped by accident. The ability to strace/debug init can be very useful if you try to figure out why it does not work as expected. However, admin should know what he does, "gdb /sbin/init 1" stops init, it can't reap orphaned zombies or take care of /etc/inittab until continued. It is even possible to crash init (and thus the whole system) if you wish, ptracer has full control. See also the long discussion: http://marc.info/?t=120628018600001 Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30ptrace: ptrace_attach: use send_sig_info() instead force_sig_specific()Oleg Nesterov
Nobody can block/ignore SIGSTOP, no need to use force_sig_specific() in ptrace_attach. Use the "regular" send_sig_info(). With this patch stracing of /sbin/init doesn't clear its SIGNAL_UNKILLABLE, but not that this makes ptracing of init safe. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30ptrace: __ptrace_unlink: use the ptrace_reparented() helperOleg Nesterov
Currently __ptrace_unlink() checks list_empty(->ptrace_list) to figure out whether the child was reparented. Change the code to use ptrace_reparented() to make this check more explicit and consistent. No functional changes. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28ptrace: conditionalize compat_ptrace_requestRoland McGrath
My recent additions to compat_ptrace_request made it mandatory for CONFIG_COMPAT arch's to define copy_siginfo_from_user32. This broke some builds, though they all really should get cleaned up in that way. Since all the arch's that actually call compat_ptrace_request have now been cleaned up to use the generic compat_sys_ptrace, we can avoid the build problems on the crufty arch's by changing the conditionals on the definition. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-21ptrace: compat_ptrace_request siginfoRoland McGrath
This adds support for PTRACE_GETSIGINFO and PTRACE_SETSIGINFO in compat_ptrace_request. It relies on existing arch definitions for copy_siginfo_to_user32 and copy_siginfo_from_user32. On powerpc, this fixes a longstanding regression of 32-bit ptrace calls on 64-bit kernels vs native calls (64-bit calls or 32-bit kernels). This can be seen in a 32-bit call using PTRACE_GETSIGINFO to examine e.g. siginfo_t.si_addr from a signal that sets it. (This was broken as of 2.6.24 and, I presume, many or all prior versions.) Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08ptrace_check_attach: remove unneeded ->signal != NULL checkOleg Nesterov
It is not possible to see the PT_PTRACED task without ->signal/sighand under tasklist_lock, release_task() does ptrace_unlink() first. If the task was already released before, ptrace_attach() can't succeed and set PT_PTRACED. Remove this check. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08kill PT_ATTACHEDOleg Nesterov
Since the patch "Fix ptrace_attach()/ptrace_traceme()/de_thread() race" commit f5b40e363ad6041a96e3da32281d8faa191597b9 we set PT_ATTACHED and change child->parent "atomically" wrt task_list lock. This means we can remove the checks like "PT_ATTACHED && ->parent != ptracer" which were needed to catch the "ptrace attach is in progress" case. We can also remove the flag itself since nobody else uses it. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06kernel/ptrace.c should #include <linux/syscalls.h>Adrian Bunk
Every file should include the headers containing the prototypes for its global functions (in this case sys_ptrace()). Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06use __set_task_state() for TRACED/STOPPED tasksOleg Nesterov
1. It is much easier to grep for ->state change if __set_task_state() is used instead of the direct assignment. 2. ptrace_stop() and handle_group_stop() use set_task_state() which adds the unneeded mb() (btw even if we use mb() it is still possible that do_wait() sees the new ->state but not ->exit_code, but this is ok). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-01Merge branch 'task_killable' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc * 'task_killable' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: (22 commits) Remove commented-out code copied from NFS NFS: Switch from intr mount option to TASK_KILLABLE Add wait_for_completion_killable Add wait_event_killable Add schedule_timeout_killable Use mutex_lock_killable in vfs_readdir Add mutex_lock_killable Use lock_page_killable Add lock_page_killable Add fatal_signal_pending Add TASK_WAKEKILL exit: Use task_is_* signal: Use task_is_* sched: Use task_contributes_to_load, TASK_ALL and TASK_NORMAL ptrace: Use task_is_* power: Use task_is_* wait: Use TASK_NORMAL proc/base.c: Use task_is_* proc/array.c: Use TASK_REPORT perfmon: Use task_is_* ... Fixed up conflicts in NFS/sunrpc manually..
2008-01-30x86: compat_sys_ptraceRoland McGrath
This adds a generic definition of compat_sys_ptrace that calls compat_arch_ptrace, parallel to sys_ptrace/arch_ptrace. Some machines needing this already define a function by that name. The new generic function is defined only on machines that put #define __ARCH_WANT_COMPAT_SYS_PTRACE into asm/ptrace.h. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: compat_ptrace_requestRoland McGrath
This adds a compat_ptrace_request that is the analogue of ptrace_request for the things that 32-on-64 ptrace implementations can share in common. So far there are just a couple of requests handled generically. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: ptrace_request peekdata/pokedataRoland McGrath
This makes ptrace_request handle {PEEK,POKE}{TEXT,DATA} directly. Every arch_ptrace that could call generic_ptrace_peekdata already has a default case calling ptrace_request, so this keeps things simpler for the arch code. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30ptrace: generic PTRACE_SINGLEBLOCKRoland McGrath
This makes ptrace_request handle PTRACE_SINGLEBLOCK along with PTRACE_CONT et al. The new generic code makes use of the arch_has_block_step macro and generic entry points on machines that define them. [ mingo@elte.hu: bugfix ] Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30ptrace: generic resumeRoland McGrath
This makes ptrace_request handle all the ptrace requests that wake up the traced task. These do low-level ptrace implementation magic that is not arch-specific and should be kept out of arch code. The implementations on each arch usually do the same thing. The new generic code makes use of the arch_has_single_step macro and generic entry points to handle PTRACE_SINGLESTEP. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-25ptrace: Call arch_ptrace_attach() when request=PTRACE_TRACEMEHaavard Skinnemoen
arch_ptrace_attach() is a hook that allows the architecture to do book-keeping after a ptrace attach. This patch adds a call to this hook when handling a PTRACE_TRACEME request as well. Currently only one architecture, m32r, implements this hook. When called, it initializes a number of debug trap slots in the ptraced task's thread struct, and it looks to me like this is the right thing to do after a PTRACE_TRACEME request as well, not only after PTRACE_ATTACH. Please correct me if I'm wrong. I want to use this hook on AVR32 to turn the debugging hardware on when a process is actually being debugged and keep it off otherwise. To be able to do this, I need to intercept PTRACE_TRACEME and PTRACE_ATTACH, as well as PTRACE_DETACH and thread exit. The latter two can be handled by existing hooks. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2008-01-02Fix kernel/ptrace.c compile problem (missing "may_attach()")Linus Torvalds
The previous commit missed one use of "may_attach()" that had been renamed to __ptrace_may_attach(). Tssk, tssk, Al. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-02restrict reading from /proc/<pid>/maps to those who share ->mm or can ptrace pidAl Viro
Contents of /proc/*/maps is sensitive and may become sensitive after open() (e.g. if target originally shares our ->mm and later does exec on suid-root binary). Check at read() (actually, ->start() of iterator) time that mm_struct we'd grabbed and locked is - still the ->mm of target - equal to reader's ->mm or the target is ptracable by reader. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-12-06ptrace: Use task_is_*Matthew Wilcox
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-10-19Isolate some explicit usage of task->tgidPavel Emelyanov
With pid namespaces this field is now dangerous to use explicitly, so hide it behind the helpers. Also the pid and pgrp fields o task_struct and signal_struct are to be deprecated. Unfortunately this patch cannot be sent right now as this leads to tons of warnings, so start isolating them, and deprecate later. Actually the p->tgid == pid has to be changed to has_group_leader_pid(), but Oleg pointed out that in case of posix cpu timers this is the same, and thread_group_leader() is more preferable. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> 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>
2007-10-19Uninline find_task_by_xxx set of functionsPavel Emelyanov
The find_task_by_something is a set of macros are used to find task by pid depending on what kind of pid is proposed - global or virtual one. All of them are wrappers above the most generic one - find_task_by_pid_type_ns() - and just substitute some args for it. It turned out, that dereferencing the current->nsproxy->pid_ns construction and pushing one more argument on the stack inline cause kernel text size to grow. This patch moves all this stuff out-of-line into kernel/pid.c. Together with the next patch it saves a bit less than 400 bytes from the .text section. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19pid namespaces: changes to show virtual ids to userPavel Emelyanov
This is the largest patch in the set. Make all (I hope) the places where the pid is shown to or get from user operate on the virtual pids. The idea is: - all in-kernel data structures must store either struct pid itself or the pid's global nr, obtained with pid_nr() call; - when seeking the task from kernel code with the stored id one should use find_task_by_pid() call that works with global pids; - when showing pid's numerical value to the user the virtual one should be used, but however when one shows task's pid outside this task's namespace the global one is to be used; - when getting the pid from userspace one need to consider this as the virtual one and use appropriate task/pid-searching functions. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: nuther build fix] [akpm@linux-foundation.org: yet nuther build fix] [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> 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>
2007-10-16m32r: convert to generic sys_ptraceChristoph Hellwig
Convert m32r to the generic sys_ptrace. The conversion requires an architecture hook after ptrace_attach which this patch adds. The hook will also be needed for a conersion of ia64 to the generic ptrace code. Thanks to Hirokazu Takata for fixing a bug in the first version of this code. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16Consolidate PTRACE_DETACHAlexey Dobriyan
Identical handlers of PTRACE_DETACH go into ptrace_request(). Not touching compat code. Not touching archs that don't call ptrace_request. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-10Fix spurious syscall tracing after PTRACE_DETACH + PTRACE_ATTACHRoland McGrath
When PTRACE_SYSCALL was used and then PTRACE_DETACH is used, the TIF_SYSCALL_TRACE flag is left set on the formerly-traced task. This means that when a new tracer comes along and does PTRACE_ATTACH, it's possible he gets a syscall tracing stop even though he's never used PTRACE_SYSCALL. This happens if the task was in the middle of a system call when the second PTRACE_ATTACH was done. The symptom is an unexpected SIGTRAP when the tracer thinks that only SIGSTOP should have been provoked by his ptrace calls so far. A few machines already fixed this in ptrace_disable (i386, ia64, m68k). But all other machines do not, and still have this bug. On x86_64, this constitutes a regression in IA32 compatibility support. Since all machines now use TIF_SYSCALL_TRACE for this, I put the clearing of TIF_SYSCALL_TRACE in the generic ptrace_detach code rather than adding it to every other machine's ptrace_disable. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19coredump masking: reimplementation of dumpable using two flagsKawai, Hidehiro
This patch changes mm_struct.dumpable to a pair of bit flags. set_dumpable() converts three-value dumpable to two flags and stores it into lower two bits of mm_struct.flags instead of mm_struct.dumpable. get_dumpable() behaves in the opposite way. [akpm@linux-foundation.org: export set_dumpable] Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17PTRACE_POKEDATA consolidationAlexey Dobriyan
Identical implementations of PTRACE_POKEDATA go into generic_ptrace_pokedata() function. AFAICS, fix bug on xtensa where successful PTRACE_POKEDATA will nevertheless return EPERM. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17PTRACE_PEEKDATA consolidationAlexey Dobriyan
Identical implementations of PTRACE_PEEKDATA go into generic_ptrace_peekdata() function. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16Use write_trylock_irqsave in ptrace_attachSripathi Kodi
This patch makes ptrace_attach use write_trylock_irqsave(). [akpm@linux-foundation.org: remove unneeded initialisation] Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> 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>
2007-05-11[PATCH] auditing ptraceAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-09-29[PATCH] pidspace: is_init()Sukadev Bhattiprolu
This is an updated version of Eric Biederman's is_init() patch. (http://lkml.org/lkml/2006/2/6/280). It applies cleanly to 2.6.18-rc3 and replaces a few more instances of ->pid == 1 with is_init(). Further, is_init() checks pid and thus removes dependency on Eric's other patches for now. Eric's original description: There are a lot of places in the kernel where we test for init because we give it special properties. Most significantly init must not die. This results in code all over the kernel test ->pid == 1. Introduce is_init to capture this case. With multiple pid spaces for all of the cases affected we are looking for only the first process on the system, not some other process that has pid == 1. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: <lxc-devel@lists.sourceforge.net> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-27[PATCH] NOMMU: Check that access_process_vm() has a valid targetDavid Howells
Check that access_process_vm() is accessing a valid mapping in the target process. This limits ptrace() accesses and accesses through /proc/<pid>/maps to only those regions actually mapped by a program. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03[PATCH] sched: cleanup, remove task_t, convert to struct task_structIngo Molnar
cleanup: remove task_t and convert all the uses to struct task_struct. I introduced it for the scheduler anno and it was a mistake. Conversion was mostly scripted, the result was reviewed and all secondary whitespace and style impact (if any) was fixed up by hand. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] coredump: kill ptrace related stuffOleg Nesterov
With this patch zap_process() sets SIGNAL_GROUP_EXIT while sending SIGKILL to the thread group. This means that a TASK_TRACED task 1. Will be awakened by signal_wake_up(1) 2. Can't sleep again via ptrace_notify() 3. Can't go to do_signal_stop() after return from ptrace_stop() in get_signal_to_deliver() So we can remove all ptrace related stuff from coredump path. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] proc: Cleanup proc_fd_access_allowedEric W. Biederman
In process of getting proc_fd_access_allowed to work it has developed a few warts. In particular the special case that always allows introspection and the special case to allow inspection of kernel threads. The special case for introspection is needed for /proc/self/mem. The special case for kernel threads really should be overridable by security modules. So consolidate these checks into ptrace.c:may_attach(). The check to always allow introspection is trivial. The check to allow access to kernel threads, and zombies is a little trickier. mem_read and mem_write already verify an mm exists so it isn't needed twice. proc_fd_access_allowed only doesn't want a check to verify task->mm exits, s it prevents all access to kernel threads. So just move the task->mm check into ptrace_attach where it is needed for practical reasons. I did a quick audit and none of the security modules in the kernel seem to care if they are passed a task without an mm into security_ptrace. So the above move should be safe and it allows security modules to come up with more restrictive policy. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-11ptrace_attach: fix possible deadlock schenario with irqsLinus Torvalds
Eric Biederman points out that we can't take the task_lock while holding tasklist_lock for writing, because another CPU that holds the task lock might take an interrupt that then tries to take tasklist_lock for writing. Which would be a nasty deadlock, with one CPU spinning forever in an interrupt handler (although admittedly you need to really work at triggering it ;) Since the ptrace_attach() code is special and very unusual, just make it be extra careful, and use trylock+repeat to avoid the possible deadlock. Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-07Fix ptrace_attach()/ptrace_traceme()/de_thread() raceLinus Torvalds
This holds the task lock (and, for ptrace_attach, the tasklist_lock) over the actual attach event, which closes a race between attacking to a thread that is either doing a PTRACE_TRACEME or getting de-threaded. Thanks to Oleg Nesterov for reminding me about this, and Chris Wright for noticing a lost return value in my first version. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-14[PATCH] fix non-leader exec under ptraceRoland McGrath
This reverts most of commit 30e0fca6c1d7d26f3f2daa4dd2b12c51dadc778a. It broke the case of non-leader MT exec when ptraced. I think the bug it was intended to fix was already addressed by commit 788e05a67c343fa22f2ae1d3ca264e7f15c25eaf. Signed-off-by: Roland McGrath <roland@redhat.com> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-02BUG_ON() Conversion in kernel/ptrace.cEric Sesterhenn
this changes if() BUG(); constructs to BUG_ON() which is cleaner, contains unlikely() and can better optimized away. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-03-28[PATCH] don't use REMOVE_LINKS/SET_LINKS for reparentingOleg Nesterov
There are places where kernel uses REMOVE_LINKS/SET_LINKS while changing process's ->parent. Use add_parent/remove_parent instead, they don't abuse of global process list. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-15[PATCH] fix zap_thread's ptrace related problemsOleg Nesterov
1. The tracee can go from ptrace_stop() to do_signal_stop() after __ptrace_unlink(p). 2. It is unsafe to __ptrace_unlink(p) while p->parent may wait for tasklist_lock in ptrace_detach(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Christoph Hellwig <hch@lst.de> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-14[PATCH] compound page: no access_process_vm checkHugh Dickins
The PageCompound check before access_process_vm's set_page_dirty_lock is no longer necessary, so remove it. But leave the PageCompound checks in bio_set_pages_dirty, dio_bio_complete and nfs_free_user_pages: at least some of those were introduced as a little optimization on hugetlb pages. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11[PATCH] move capable() to capability.hRandy.Dunlap
- Move capable() from sched.h to capability.h; - Use <linux/capability.h> where capable() is used (in include/, block/, ipc/, kernel/, a few drivers/, mm/, security/, & sound/; many more drivers/ to go) Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] use ptrace_get_task_struct in various placesChristoph Hellwig
The ptrace_get_task_struct() helper that I added as part of the ptrace consolidation is useful in variety of places that currently opencode it. Switch them to the common helpers. Add a ptrace_traceme() helper that needs to be explicitly called, and simplify the ptrace_get_task_struct() interface. We don't need the request argument now, and we return the task_struct directly, using ERR_PTR() for error returns. It's a bit more code in the callers, but we have two sane routines that do one thing well now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-29[PATCH] Fix crash when ptrace poking hugepage areasDavid Gibson
set_page_dirty() will not cope with being handed a page * which is part of a compound page, but not the master page in that compound page. This case can occur via access_process_vm() if you attemp to write to another process's hugepage memory area using ptrace() (causing an oops or hang). This patch fixes the bug by only calling set_page_dirty() from access_process_vm() if the page is not a compound page. We already use a similar fix in bio_set_pages_dirty() for the case of direct io to hugepages. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: William Irwin <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13[PATCH] fix task_struct leak in ptraceChristoph Hellwig
When ptrace_attach fails we need to drop the task_struct reference. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09Fix ptrace self-attach ruleLinus Torvalds
Before we did CLONE_THREAD, the way to check whether we were attaching to ourselves was to just check "current == task", but with CLONE_THREAD we should check that the thread group ID matches instead. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] consolidate sys_ptrace()Christoph Hellwig
The sys_ptrace boilerplate code (everything outside the big switch statement for the arch-specific requests) is shared by most architectures. This patch moves it to kernel/ptrace.c and leaves the arch-specific code as arch_ptrace. Some architectures have a too different ptrace so we have to exclude them. They continue to keep their implementations. For sh64 I had to add a sh64_ptrace wrapper because it does some initialization on the first call. For um I removed an ifdefed SUBARCH_PTRACE_SPECIAL block, but SUBARCH_PTRACE_SPECIAL isn't defined anywhere in the tree. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Paul Mackerras <paulus@samba.org> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-By: David Howells <dhowells@redhat.com> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>