The patch titled
Subject: ptrace: don't modify flags on PTRACE_SETOPTIONS failure
has been added to the -mm tree. Its filename is
ptrace-dont-modify-flags-on-ptrace_setoptions-failure.patch
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From: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>
Subject: ptrace: don't modify flags on PTRACE_SETOPTIONS failure
On ptrace(PTRACE_SETOPTIONS, pid, 0, <opts>), we used to set those option
bits which are known, and then fail with -EINVAL if there are some unknown
bits in <opts>.
This is inconsistent with typical error handling, which does not change
any state if input is invalid.
This patch changes PTRACE_SETOPTIONS behavior so that in this case, we
return -EINVAL and don't change any bits in task->ptrace.
It's very unlikely that there is userspace code in the wild which will be
affected by this change: it should have the form
ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_BOGUSOPT)
where PTRACE_O_BOGUSOPT is a constant unknown to the kernel. But kernel
headers, naturally, don't contain any PTRACE_O_BOGUSOPTs, thus the only
way userspace can use one if it defines one itself. I can't see why
anyone would do such a thing deliberately.
Signed-off-by: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Pedro Alves <palves@xxxxxxxxxx>
Cc: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/ptrace.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff -puN kernel/ptrace.c~ptrace-dont-modify-flags-on-ptrace_setoptions-failure kernel/ptrace.c
--- a/kernel/ptrace.c~ptrace-dont-modify-flags-on-ptrace_setoptions-failure
+++ a/kernel/ptrace.c
@@ -528,6 +528,9 @@ int ptrace_writedata(struct task_struct
static int ptrace_setoptions(struct task_struct *child, unsigned long data)
{
+ if (data & ~(unsigned long)PTRACE_O_MASK)
+ return -EINVAL;
+
child->ptrace &= ~PT_TRACE_MASK;
if (data & PTRACE_O_TRACESYSGOOD)
@@ -551,7 +554,7 @@ static int ptrace_setoptions(struct task
if (data & PTRACE_O_TRACEEXIT)
child->ptrace |= PT_TRACE_EXIT;
- return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
+ return 0;
}
static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
_
Subject: Subject: ptrace: don't modify flags on PTRACE_SETOPTIONS failure
Patches currently in -mm which might be from vda.linux@xxxxxxxxxxxxxx are
linux-next.patch
kernel-exitc-if-init-dies-log-a-signal-which-killed-it-if-any.patch
kernel-exitc-if-init-dies-log-a-signal-which-killed-it-if-any-fix.patch
ptrace-the-killed-tracee-should-not-enter-the-syscall.patch
ptrace-dont-send-sigtrap-on-exec-if-seized.patch
ptrace-dont-modify-flags-on-ptrace_setoptions-failure.patch
ptrace-simplify-ptrace_foo-constants-and-ptrace_setoptions-code.patch
ptrace-make-ptrace_seize-set-ptrace-options-specified-in-data-parameter.patch
ptrace-renumber-ptrace_event_stop-so-that-future-new-options-and-events-can-match.patch
ptrace-remove-ptrace_seize_devel-bit.patch
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