From ce29856a5e1aabe52e18b2c60db1490769a6ab55 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Micka=C3=ABl=20Sala=C3=BCn?= Date: Mon, 1 Aug 2016 23:01:56 +0200 Subject: [PATCH] um/ptrace: Fix the syscall number update after a ptrace MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Update the syscall number after each PTRACE_SETREGS on ORIG_*AX. This is needed to get the potentially altered syscall number in the seccomp filters after RET_TRACE. This fix four seccomp_bpf tests: > [ RUN ] TRACE_syscall.skip_after_RET_TRACE > seccomp_bpf.c:1560:TRACE_syscall.skip_after_RET_TRACE:Expected -1 (18446744073709551615) == syscall(39) (26) > seccomp_bpf.c:1561:TRACE_syscall.skip_after_RET_TRACE:Expected 1 (1) == (*__errno_location ()) (22) > [ FAIL ] TRACE_syscall.skip_after_RET_TRACE > [ RUN ] TRACE_syscall.kill_after_RET_TRACE > TRACE_syscall.kill_after_RET_TRACE: Test exited normally instead of by signal (code: 1) > [ FAIL ] TRACE_syscall.kill_after_RET_TRACE > [ RUN ] TRACE_syscall.skip_after_ptrace > seccomp_bpf.c:1622:TRACE_syscall.skip_after_ptrace:Expected -1 (18446744073709551615) == syscall(39) (26) > seccomp_bpf.c:1623:TRACE_syscall.skip_after_ptrace:Expected 1 (1) == (*__errno_location ()) (22) > [ FAIL ] TRACE_syscall.skip_after_ptrace > [ RUN ] TRACE_syscall.kill_after_ptrace > TRACE_syscall.kill_after_ptrace: Test exited normally instead of by signal (code: 1) > [ FAIL ] TRACE_syscall.kill_after_ptrace Fixes: 26703c636c1f ("um/ptrace: run seccomp after ptrace") Signed-off-by: Mickaël Salaün Acked-by: Kees Cook Cc: Jeff Dike Cc: Richard Weinberger Cc: James Morris Cc: user-mode-linux-devel@lists.sourceforge.net Signed-off-by: James Morris Signed-off-by: Kees Cook --- arch/um/kernel/skas/syscall.c | 5 ----- arch/x86/um/ptrace_32.c | 3 +++ arch/x86/um/ptrace_64.c | 4 ++++ 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index 0728fee94398..b783ac87d98a 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -27,12 +27,7 @@ void handle_syscall(struct uml_pt_regs *r) if (secure_computing(NULL) == -1) goto out; - /* Update the syscall number after orig_ax has potentially been updated - * with ptrace. - */ - UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp); syscall = UPT_SYSCALL_NR(r); - if (syscall >= 0 && syscall <= __NR_syscall_max) PT_REGS_SET_SYSCALL_RETURN(regs, EXECUTE_SYSCALL(syscall, regs)); diff --git a/arch/x86/um/ptrace_32.c b/arch/x86/um/ptrace_32.c index ebd4dd6ef73b..a7ef7b131e25 100644 --- a/arch/x86/um/ptrace_32.c +++ b/arch/x86/um/ptrace_32.c @@ -84,7 +84,10 @@ int putreg(struct task_struct *child, int regno, unsigned long value) case EAX: case EIP: case UESP: + break; case ORIG_EAX: + /* Update the syscall number. */ + UPT_SYSCALL_NR(&child->thread.regs.regs) = value; break; case FS: if (value && (value & 3) != 3) diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c index faab418876ce..0b5c184dd5b3 100644 --- a/arch/x86/um/ptrace_64.c +++ b/arch/x86/um/ptrace_64.c @@ -78,7 +78,11 @@ int putreg(struct task_struct *child, int regno, unsigned long value) case RSI: case RDI: case RBP: + break; + case ORIG_RAX: + /* Update the syscall number. */ + UPT_SYSCALL_NR(&child->thread.regs.regs) = value; break; case FS: -- 2.30.2