git: 47f7345baba0 - main - linux: fix PTRACE_POKEDATA and PTRACE_POKETEXT.

[Konstantin Belousov]

On Tue, Jan 19, 2021 at 10:53:38AM +0000, Edward Tomasz Napierala wrote:
> The branch main has been updated by trasz:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=47f7345baba01121e29c22b43f68345399a32912
> 
> commit 47f7345baba01121e29c22b43f68345399a32912
> Author:     Edward Tomasz Napierala <trasz at FreeBSD.org>
> AuthorDate: 2021-01-15 16:57:24 +0000
> Commit:     Edward Tomasz Napierala <trasz at FreeBSD.org>
> CommitDate: 2021-01-19 10:30:55 +0000
> 
>     linux: fix PTRACE_POKEDATA and PTRACE_POKETEXT.
>     
>     Sponsored by:   The FreeBSD Foundation
> ---
>  sys/amd64/linux/linux_ptrace.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/sys/amd64/linux/linux_ptrace.c b/sys/amd64/linux/linux_ptrace.c
> index a14155ed7e97..c1d05db5bc42 100644
> --- a/sys/amd64/linux/linux_ptrace.c
> +++ b/sys/amd64/linux/linux_ptrace.c
> @@ -594,10 +594,15 @@ linux_ptrace(struct thread *td, struct linux_ptrace_args *uap)
>  		error = linux_ptrace_peekuser(td, pid, addr, (void *)uap->data);
>  		break;
>  	case LINUX_PTRACE_POKETEXT:
> -		error = kern_ptrace(td, PT_WRITE_I, pid, addr, uap->data);
> -		break;
This is wrong. You should access text AS if linux request was for text.

>  	case LINUX_PTRACE_POKEDATA:
>  		error = kern_ptrace(td, PT_WRITE_D, pid, addr, uap->data);
> +		if (error != 0)
> +			return (error);
> +		/*
> +		 * Linux expects this syscall to write 64 bits, not 32.
> +		 */
> +		error = kern_ptrace(td, PT_WRITE_D, pid,
> +		    (void *)(uap->addr + 4), uap->data >> 32);
>  		break;
You should use PT_IO there instead of doing two accesses (to the wrong AS).

>  	case LINUX_PTRACE_POKEUSER:
>  		error = linux_ptrace_pokeuser(td, pid, addr, (void *)uap->data);