move seccomp from /proc to a prctl
This reduces the memory footprint and it enforces that only the current task can enable seccomp on itself (this is a requirement for a strightforward [modulo preempt ;) ] TIF_NOTSC implementation). Signed-off-by: Andrea Arcangeli <andrea@cpushare.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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committed by
Linus Torvalds

parent
be0ef957c9
commit
1d9d02feee
@@ -10,6 +10,7 @@
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#include <linux/sched.h>
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/* #define SECCOMP_DEBUG 1 */
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#define NR_SECCOMP_MODES 1
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/*
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* Secure computing mode 1 allows only read/write/exit/sigreturn.
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@@ -54,3 +55,28 @@ void __secure_computing(int this_syscall)
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#endif
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do_exit(SIGKILL);
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}
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long prctl_get_seccomp(void)
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{
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return current->seccomp.mode;
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}
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long prctl_set_seccomp(unsigned long seccomp_mode)
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{
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long ret;
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/* can set it only once to be even more secure */
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ret = -EPERM;
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if (unlikely(current->seccomp.mode))
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goto out;
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ret = -EINVAL;
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if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
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current->seccomp.mode = seccomp_mode;
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set_thread_flag(TIF_SECCOMP);
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ret = 0;
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}
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out:
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return ret;
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}
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