Commit 7af20b60 authored Mar 29, 2019 by Dmitry V. Levin Committed by Greg Kroah-Hartman Apr 17, 2019

riscv: Fix syscall_get_arguments() and syscall_set_arguments()

commit 10a16997db3d99fc02c026cf2c6e6c670acafab0 upstream.

RISC-V syscall arguments are located in orig_a0,a1..a5 fields
of struct pt_regs.

Due to an off-by-one bug and a bug in pointer arithmetic
syscall_get_arguments() was reading s3..s7 fields instead of a1..a5.
Likewise, syscall_set_arguments() was writing s3..s7 fields
instead of a1..a5.

Link: http://lkml.kernel.org/r/20190329171221.GA32456@altlinux.org



Fixes: e2c0cdfb ("RISC-V: User-facing API")
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: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Cc: stable@vger.kernel.org # v4.15+
Acked-by: Palmer Dabbelt <palmer@sifive.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>

parent 54fb5c9d

arch/riscv/include/asm/syscall.h

+7 −5

Original line number	Diff line number	Diff line
		@@ -78,10 +78,11 @@ static inline void syscall_get_arguments(struct task_struct *task,
		if (i == 0) {
		args[0] = regs->orig_a0;
		args++;
		i++;
		n--;
		} else {
		i--;
		}
		memcpy(args, &regs->a1 + i * sizeof(regs->a1), n * sizeof(args[0]));
		memcpy(args, &regs->a1 + i, n * sizeof(args[0]));
		}

		static inline void syscall_set_arguments(struct task_struct *task,
		@@ -93,10 +94,11 @@ static inline void syscall_set_arguments(struct task_struct *task,
		if (i == 0) {
		regs->orig_a0 = args[0];
		args++;
		i++;
		n--;
		} else {
		i--;
		}
		memcpy(&regs->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
		memcpy(&regs->a1 + i, args, n * sizeof(regs->a1));
		}

		#endif /* _ASM_RISCV_SYSCALL_H */