BackPup/Linux
1
0 Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-10-07 05:31:08 -04:00
Code Issues Packages Projects Releases Wiki Activity

lib/syscall: Pin the task stack in collect_syscall()

Browse Source 
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 <[email protected]>
Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/0bfd8e6d4729c97745d3781a29610a33d0a8091d.1474003868.git.luto@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Andy Lutomirski authored and Ingo Molnar committed 2016-09-16 09:18:53 +02:00
1 parent 74327a3e88
commit aa1f1a6396
1 file changed
+13 -2
Download Patch File Download Diff File Expand all files Collapse all files
lib/syscall.c
+13 -2
View File
@@ -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;
}