From: Dmitry V. Levin ldv@altlinux.org
commit ed3bb007021b9bddb90afae28a19f08ed8890add upstream.
C-SKY syscall arguments are located in orig_a0,a1,a2,a3,regs[0],regs[1] fields of struct pt_regs.
Due to an off-by-one bug and a bug in pointer arithmetic syscall_get_arguments() was reading orig_a0,regs[1..5] fields instead. Likewise, syscall_set_arguments() was writing orig_a0,regs[1..5] fields instead.
Link: http://lkml.kernel.org/r/20190329171230.GB32456@altlinux.org
Fixes: 4859bfca11c7d ("csky: System Call") Cc: Ingo Molnar mingo@redhat.com Cc: Kees Cook keescook@chromium.org Cc: Andy Lutomirski luto@amacapital.net Cc: Will Drewry wad@chromium.org Cc: stable@vger.kernel.org # v4.20+ Tested-by: Guo Ren ren_guo@c-sky.com Acked-by: Guo Ren ren_guo@c-sky.com Signed-off-by: Dmitry V. Levin ldv@altlinux.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/csky/include/asm/syscall.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/arch/csky/include/asm/syscall.h +++ b/arch/csky/include/asm/syscall.h @@ -49,10 +49,11 @@ syscall_get_arguments(struct task_struct if (i == 0) { args[0] = regs->orig_a0; args++; - i++; n--; + } else { + i--; } - memcpy(args, ®s->a1 + i * sizeof(regs->a1), n * sizeof(args[0])); + memcpy(args, ®s->a1 + i, n * sizeof(args[0])); }
static inline void @@ -63,10 +64,11 @@ syscall_set_arguments(struct task_struct if (i == 0) { regs->orig_a0 = args[0]; args++; - i++; n--; + } else { + i--; } - memcpy(®s->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0)); + memcpy(®s->a1 + i, args, n * sizeof(regs->a1)); }
static inline int