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authorMickaël Salaün <mic@digikod.net>2015-12-29 23:35:44 +0300
committerRichard Weinberger <richard@nod.at>2016-01-10 23:49:48 +0300
commite04c989eb785af61d2895d76d38c09166296f9c5 (patch)
treea4698bceed0851ec151539c275e5d615da506d36 /arch/um
parenta7df4716d19594b7b3f106f0bc0ca1c548e508e6 (diff)
downloadlinux-e04c989eb785af61d2895d76d38c09166296f9c5.tar.xz
um: Fix ptrace GETREGS/SETREGS bugs
This fix two related bugs: * PTRACE_GETREGS doesn't get the right orig_ax (syscall) value * PTRACE_SETREGS can't set the orig_ax value (erased by initial value) Get rid of the now useless and error-prone get_syscall(). Fix inconsistent behavior in the ptrace implementation for i386 when updating orig_eax automatically update the syscall number as well. This is now updated in handle_syscall(). Signed-off-by: Mickaël Salaün <mic@digikod.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Anton Ivanov <aivanov@brocade.com> Cc: Meredydd Luff <meredydd@senatehouse.org> Cc: David Drysdale <drysdale@google.com> Signed-off-by: Richard Weinberger <richard@nod.at> Acked-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/include/shared/os.h1
-rw-r--r--arch/um/kernel/skas/syscall.c26
-rw-r--r--arch/um/os-Linux/skas/process.c7
3 files changed, 14 insertions, 20 deletions
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 7a04ddd85334..de5d572225f3 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -284,7 +284,6 @@ extern void initial_thread_cb_skas(void (*proc)(void *),
void *arg);
extern void halt_skas(void);
extern void reboot_skas(void);
-extern int get_syscall(struct uml_pt_regs *regs);
/* irq.c */
extern int os_waiting_for_events(struct irq_fd *active_fds);
diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c
index 1683b8efdfda..6cadce761bcf 100644
--- a/arch/um/kernel/skas/syscall.c
+++ b/arch/um/kernel/skas/syscall.c
@@ -7,29 +7,31 @@
#include <linux/ptrace.h>
#include <kern_util.h>
#include <sysdep/ptrace.h>
+#include <sysdep/ptrace_user.h>
#include <sysdep/syscalls.h>
-#include <os.h>
void handle_syscall(struct uml_pt_regs *r)
{
struct pt_regs *regs = container_of(r, struct pt_regs, regs);
- long result;
int syscall;
- if (syscall_trace_enter(regs)) {
- result = -ENOSYS;
+ /* Initialize the syscall number and default return value. */
+ UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
+ PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);
+
+ if (syscall_trace_enter(regs))
goto out;
- }
- syscall = get_syscall(r);
+ /* 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 > __NR_syscall_max) || syscall < 0)
- result = -ENOSYS;
- else
- result = EXECUTE_SYSCALL(syscall, regs);
+ if (syscall >= 0 && syscall <= __NR_syscall_max)
+ PT_REGS_SET_SYSCALL_RETURN(regs,
+ EXECUTE_SYSCALL(syscall, regs));
out:
- PT_REGS_SET_SYSCALL_RETURN(regs, result);
-
syscall_trace_leave(regs);
}
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index b856c66ebd3a..23025d645160 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -172,13 +172,6 @@ static void handle_trap(int pid, struct uml_pt_regs *regs,
handle_syscall(regs);
}
-int get_syscall(struct uml_pt_regs *regs)
-{
- UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp);
-
- return UPT_SYSCALL_NR(regs);
-}
-
extern char __syscall_stub_start[];
static int userspace_tramp(void *stack)