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parisc: Fix and enable seccomp filter support

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The seccomp filter support requires careful handling of task registers.  This
includes reloading of the return value (%r28) and proper syscall exit if
secure_computing() returned -1.

Additionally we need to sign-extend the syscall number from signed 32bit to
signed 64bit in do_syscall_trace_enter() since the ptrace interface only allows
storing 32bit values in compat mode.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v4.5
This commit is contained in:
Helge Deller
2016-03-30 14:14:31 +02:00
parent 4f4acc9472
commit 910cd32e55
4 changed files with 23 additions and 2 deletions
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9
arch/parisc/kernel/ptrace.c
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@@ -270,7 +270,8 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
long do_syscall_trace_enter(struct pt_regs *regs)
{
/* Do the secure computing check first. */
secure_computing_strict(regs->gr[20]);
if (secure_computing() == -1)
return -1;
if (test_thread_flag(TIF_SYSCALL_TRACE) &&
tracehook_report_syscall_entry(regs)) {
@@ -296,7 +297,11 @@ long do_syscall_trace_enter(struct pt_regs *regs)
regs->gr[23] & 0xffffffff);
out:
return regs->gr[20];
/*
* Sign extend the syscall number to 64bit since it may have been
* modified by a compat ptrace call
*/
return (int) ((u32) regs->gr[20]);
}
void do_syscall_trace_exit(struct pt_regs *regs)