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authorOleg Nesterov <oleg@redhat.com>2012-12-18 04:03:07 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-18 05:15:22 +0400
commit992fb6e170639b0849bace8e49bf31bd37c4123c (patch)
tree29f54e489ea095aba284fd4b1feb7201347eb70c /include
parent462e471107624fe9bd8b6353ac13e06305c3f3fd (diff)
downloadlinux-992fb6e170639b0849bace8e49bf31bd37c4123c.tar.xz
ptrace: introduce PTRACE_O_EXITKILL
Ptrace jailers want to be sure that the tracee can never escape from the control. However if the tracer dies unexpectedly the tracee continues to run in potentially unsafe mode. Add the new ptrace option PTRACE_O_EXITKILL. If the tracer exits it sends SIGKILL to every tracee which has this bit set. Note that the new option is not equal to the last-option << 1. Because currently all options have an event, and the new one starts the eventless group. It uses the random 20 bit, so we have the room for 12 more events, but we can also add the new eventless options below this one. Suggested by Amnon Shiloh. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Amnon Shiloh <u3557@miso.sublimeip.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: Chris Evans <scarybeasts@gmail.com> Cc: David Howells <dhowells@redhat.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>
Diffstat (limited to 'include')
-rw-r--r--include/linux/ptrace.h2
-rw-r--r--include/uapi/linux/ptrace.h5
2 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index a89ff04bddd9..addfbe7c180e 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -32,6 +32,8 @@
#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
+#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
+
/* single stepping state bits (used on ARM and PA-RISC) */
#define PT_SINGLESTEP_BIT 31
#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h
index 1ef6c056a9e4..022ab186a812 100644
--- a/include/uapi/linux/ptrace.h
+++ b/include/uapi/linux/ptrace.h
@@ -73,7 +73,10 @@
#define PTRACE_O_TRACEEXIT (1 << PTRACE_EVENT_EXIT)
#define PTRACE_O_TRACESECCOMP (1 << PTRACE_EVENT_SECCOMP)
-#define PTRACE_O_MASK 0x000000ff
+/* eventless options */
+#define PTRACE_O_EXITKILL (1 << 20)
+
+#define PTRACE_O_MASK (0x000000ff | PTRACE_O_EXITKILL)
#include <asm/ptrace.h>