diff options
| author | Mickaël Salaün <mic@digikod.net> | 2016-08-01 23:01:56 +0200 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2016-09-07 09:25:04 -0700 |
| commit | ce29856a5e1aabe52e18b2c60db1490769a6ab55 (patch) | |
| tree | 01c68cc9c5bd546965d623fdec11596a50cc8a0b | |
| parent | 972939e28592ec61e2e8334786152be2c80de677 (diff) | |
| download | lwn-ce29856a5e1aabe52e18b2c60db1490769a6ab55.tar.gz lwn-ce29856a5e1aabe52e18b2c60db1490769a6ab55.zip | |
um/ptrace: Fix the syscall number update after a ptrace
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 <mic@digikod.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: James Morris <jmorris@namei.org>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | arch/um/kernel/skas/syscall.c | 5 | ||||
| -rw-r--r-- | arch/x86/um/ptrace_32.c | 3 | ||||
| -rw-r--r-- | 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: |