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| author | Mickaël Salaün <mic@digikod.net> | 2015-12-29 21:35:44 +0100 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2016-01-10 21:49:48 +0100 |
| commit | e04c989eb785af61d2895d76d38c09166296f9c5 (patch) | |
| tree | a4698bceed0851ec151539c275e5d615da506d36 /arch/um | |
| parent | a7df4716d19594b7b3f106f0bc0ca1c548e508e6 (diff) | |
| download | linux-stable-e04c989eb785af61d2895d76d38c09166296f9c5.tar.gz linux-stable-e04c989eb785af61d2895d76d38c09166296f9c5.tar.bz2 linux-stable-e04c989eb785af61d2895d76d38c09166296f9c5.zip | |
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.h | 1 | ||||
| -rw-r--r-- | arch/um/kernel/skas/syscall.c | 26 | ||||
| -rw-r--r-- | arch/um/os-Linux/skas/process.c | 7 |
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) |