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Groups > linux.kernel > #1482788
| From | Andy Lutomirski <luto@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 10/12] lib/syscall: Pin the task stack in collect_syscall() |
| Date | 2016-09-13 23:40 +0200 |
| Message-ID | <sh3AS-7tK-15@gated-at.bofh.it> (permalink) |
| References | <sh3rc-7o2-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
This will avoid a potential read-after-free if collect_syscall()
(e.g. /proc/PID/syscall) is called on an exiting task.
Reported-by: Jann Horn <jann@thejh.net>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
lib/syscall.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/lib/syscall.c b/lib/syscall.c
index e30e03932480..63239e097b13 100644
--- a/lib/syscall.c
+++ b/lib/syscall.c
@@ -7,9 +7,19 @@ static int collect_syscall(struct task_struct *target, long *callno,
unsigned long args[6], unsigned int maxargs,
unsigned long *sp, unsigned long *pc)
{
- struct pt_regs *regs = task_pt_regs(target);
- if (unlikely(!regs))
+ struct pt_regs *regs;
+
+ if (!try_get_task_stack(target)) {
+ /* Task has no stack, so the task isn't in a syscall. */
+ *callno = -1;
+ return 0;
+ }
+
+ regs = task_pt_regs(target);
+ if (unlikely(!regs)) {
+ put_task_stack(target);
return -EAGAIN;
+ }
*sp = user_stack_pointer(regs);
*pc = instruction_pointer(regs);
@@ -18,6 +28,7 @@ static int collect_syscall(struct task_struct *target, long *callno,
if (*callno != -1L && maxargs > 0)
syscall_get_arguments(target, regs, 0, maxargs, args);
+ put_task_stack(target);
return 0;
}
--
2.7.4
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[PATCH 00/12] thread_info cleanups and stack caching Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:30 +0200
[PATCH 03/12] um: Stop conflating task_struct::stack with thread_info Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:30 +0200
Re: [PATCH 03/12] um: Stop conflating task_struct::stack with thread_info Ingo Molnar <mingo@kernel.org> - 2016-09-15 08:30 +0200
[tip:x86/asm] um/Stop conflating task_struct::stack with thread_info tip-bot for Linus Torvalds <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 12/12] fork: Cache two thread stacks per cpu if CONFIG_VMAP_STACK is set Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 01/12] x86/asm: Move 'status' from struct thread_info to struct thread_struct Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[tip:x86/asm] x86/asm: Move the thread_info::status field to thread_struct tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 10/12] lib/syscall: Pin the task stack in collect_syscall() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-14 17:00 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-14 20:30 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-14 20:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-15 20:10 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-15 20:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-15 20:50 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-15 21:20 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Peter Zijlstra <peterz@infradead.org> - 2016-09-16 09:50 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-16 17:20 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@kernel.org> - 2016-09-16 17:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Peter Zijlstra <peterz@infradead.org> - 2016-09-16 18:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Peter Zijlstra <peterz@infradead.org> - 2016-09-16 17:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Ingo Molnar <mingo@kernel.org> - 2016-09-15 08:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Ingo Molnar <mingo@kernel.org> - 2016-09-15 11:30 +0200
[PATCH 09/12] x86/process: Pin the target stack in get_wchan() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Jann Horn <jann@thejh.net> - 2016-09-17 04:10 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Andy Lutomirski <luto@amacapital.net> - 2016-09-23 00:50 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Andy Lutomirski <luto@amacapital.net> - 2016-09-23 01:00 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Jann Horn <jann@thejh.net> - 2016-09-23 09:50 +0200
[PATCH 06/12] sched: Add try_get_task_stack() and put_task_stack() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 02/12] x86/entry: Get rid of pt_regs_to_thread_info() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
Re: [PATCH 02/12] x86/entry: Get rid of pt_regs_to_thread_info() Ingo Molnar <mingo@kernel.org> - 2016-09-15 08:30 +0200
[tip:x86/asm] x86/entry: Get rid of pt_regs_to_thread_info() tip-bot for Linus Torvalds <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 05/12] x86: Move thread_info into task_struct Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[tip:x86/asm] x86: Move thread_info into task_struct tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 04/12] sched: Allow putting thread_info into task_struct Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[tip:x86/asm] sched/core: Allow putting thread_info into task_struct tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 11/12] sched: Free the stack early if CONFIG_THREAD_INFO_IN_TASK Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 07/12] kthread: to_live_kthread() needs try_get_task_stack() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
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