From: Dmitry V. Levin ldv@altlinux.org
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: e2c0cdfba7f69 ("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
--- arch/riscv/include/asm/syscall.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
--- a/arch/riscv/include/asm/syscall.h +++ b/arch/riscv/include/asm/syscall.h @@ -78,10 +78,11 @@ static inline void syscall_get_arguments 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 syscall_set_arguments(struct task_struct *task, @@ -93,10 +94,11 @@ static inline void syscall_set_arguments if (i == 0) { regs->orig_a0 = args[0]; args++; - i++; n--; - } - memcpy(®s->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0)); + } else { + i--; + } + memcpy(®s->a1 + i, args, n * sizeof(regs->a1)); }
#endif /* _ASM_RISCV_SYSCALL_H */