Re: [PATCH] riscv: reject invalid syscalls below -1

Andreas Schwab
2019-12-18T09:46:11Z

On Dez 18 2019, David Abdurachmanov wrote:

> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index a1349ca64669..e163b7b64c86 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -246,6 +246,7 @@ check_syscall_nr:
> */
> li t1, -1
> beq a7, t1, ret_from_syscall_rejected
> + blt a7, t1, 1f

How about using bgeu instead in the preceding check?

/*
* Syscall number held in a7.
* If syscall number is above allowed value, redirect to ni_syscall.
*/
bge a7, t0, 1f

Andreas.

--
Andreas Schwab, SUSE Labs, schwab@suse.de
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