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authorMickaël Salaün <mic@digikod.net>2016-08-01 23:01:56 +0200
committerKees Cook <keescook@chromium.org>2016-09-07 09:25:04 -0700
commitce29856a5e1aabe52e18b2c60db1490769a6ab55 (patch)
tree01c68cc9c5bd546965d623fdec11596a50cc8a0b
parent972939e28592ec61e2e8334786152be2c80de677 (diff)
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.c5
-rw-r--r--arch/x86/um/ptrace_32.c3
-rw-r--r--arch/x86/um/ptrace_64.c4
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: