Messages in this thread Patch in this message | | | Date | Fri, 10 Feb 2012 18:32:59 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 1/2] ptrace: the killed tracee should not enter the syscall |
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Another old/known problem. If the tracee is killed after it reports syscall_entry, it starts the syscall and debugger can't control this. This confuses the users and this creates the security problems for ptrace jailers.
Change tracehook_report_syscall_entry() to return non-zero if killed, this instructs syscall_trace_enter() to abort the syscall.
Reported-by: Chris Evans <scarybeasts@gmail.com> Tested-by: Indan Zupancic <indan@nul.nu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- include/linux/tracehook.h | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index a71a292..51bd91d 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -54,12 +54,12 @@ struct linux_binprm; /* * ptrace report for syscall entry and exit looks identical. */ -static inline void ptrace_report_syscall(struct pt_regs *regs) +static inline int ptrace_report_syscall(struct pt_regs *regs) { int ptrace = current->ptrace; if (!(ptrace & PT_PTRACED)) - return; + return 0; ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); @@ -72,6 +72,8 @@ static inline void ptrace_report_syscall(struct pt_regs *regs) send_sig(current->exit_code, current, 1); current->exit_code = 0; } + + return fatal_signal_pending(current); } /** @@ -96,8 +98,7 @@ static inline void ptrace_report_syscall(struct pt_regs *regs) static inline __must_check int tracehook_report_syscall_entry( struct pt_regs *regs) { - ptrace_report_syscall(regs); - return 0; + return ptrace_report_syscall(regs); } /** -- 1.5.5.1
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