On Thu, 2022-11-03 at 03:50 -0400, guoren@xxxxxxxxxx wrote:
[...]
> --- a/arch/riscv/kernel/sys_riscv.c
> +++ b/arch/riscv/kernel/sys_riscv.c
[...]
> +asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
> +{
> + syscall_t syscall;
> + ulong nr = regs->a7;
> +
> + regs->epc += 4;
> + regs->orig_a0 = regs->a0;
> + regs->a0 = -ENOSYS;
> +
> + nr = syscall_enter_from_user_mode(regs, nr);
> +#ifdef CONFIG_COMPAT
> + if ((regs->status & SR_UXL) == SR_UXL_32)
> + syscall = compat_sys_call_table[nr];
> + else
> +#endif
> + syscall = sys_call_table[nr];
> +
> + if (nr < NR_syscalls)
This bounds check needs to be done before indexing the system call
table, not after.
Ben.
> + regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
> + regs->a3, regs->a4, regs->a5, regs->a6);
> + syscall_exit_to_user_mode(regs);
> +}
[...]
--
Ben Hutchings
This sentence contradicts itself - no actually it doesn't.
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