From: Dmitry V. Levin <ldv@xxxxxxxxxxxx> 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@xxxxxxxxxxxx Fixes: e2c0cdfba7f69 ("RISC-V: User-facing API") Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Will Drewry <wad@xxxxxxxxxxxx> Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx> Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx # v4.15+ Acked-by: Palmer Dabbelt <palmer@xxxxxxxxxx> Signed-off-by: Dmitry V. Levin <ldv@xxxxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 */