Re: [PATCH glibc] _hurd_intr_rpc_mach_msg: handle message iteration correctly.

[Samuel Thibault]

Applied, thanks!

Flavio Cruz, le sam. 18 nov. 2023 18:18:44 -0500, a ecrit:
> The `ty` pointer is only set at the end of the loop so that
> `msgtl_header.msgt_inline` and `msgtl_header.msgt_deallocate` remain
> valid. Also, when deallocating memory, we use the length from the
> message directly rather than hard coding mach_port_t since we want to
> deallocate any kind of OOL data.
> ---
>  hurd/intr-msg.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/hurd/intr-msg.c b/hurd/intr-msg.c
> index 98f588f2..737bfe0f 100644
> --- a/hurd/intr-msg.c
> +++ b/hurd/intr-msg.c
> @@ -186,12 +186,14 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
>             mach_msg_type_size_t size;
>             mach_msg_type_number_t number;
>  
> -           inline void clean_ports (mach_port_t *ports, int dealloc)
> +           inline void clean_ports_and_memory (char *data, const vm_size_t 
> length,
> +                                             int dealloc)
>               {
>                 mach_msg_type_number_t i;
>                 switch (name)
>                   {
>                   case MACH_MSG_TYPE_MOVE_SEND:
> +                   mach_port_t *ports = (mach_port_t *) data;
>                     for (i = 0; i < number; i++)
>                       __mach_port_deallocate (__mach_task_self (), *ports++);
>                     if (ty->msgtl_header.msgt_longform)
> @@ -207,40 +209,38 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
>                       assert (! "unexpected port type in interruptible RPC");
>                   }
>                 if (dealloc)
> -                 __vm_deallocate (__mach_task_self (),
> -                                  (vm_address_t) ports,
> -                                  number * sizeof (mach_port_t));
> +                 __vm_deallocate (__mach_task_self (), (vm_address_t) data, 
> length);
>               }
>  
> +           char *data;
>             if (ty->msgtl_header.msgt_longform)
>               {
>                 name = ty->msgtl_name;
>                 size = ty->msgtl_size;
>                 number = ty->msgtl_number;
> -               ty = (void *) ty + sizeof (mach_msg_type_long_t);
> +               data = (char *) ty + sizeof (mach_msg_type_long_t);
>               }
>             else
>               {
>                 name = ty->msgtl_header.msgt_name;
>                 size = ty->msgtl_header.msgt_size;
>                 number = ty->msgtl_header.msgt_number;
> -               ty = (void *) ty + sizeof (mach_msg_type_t);
> +               data = (char *) ty + sizeof (mach_msg_type_t);
>               }
>  
> +           const vm_size_t length = ((number * size) + 7) >> 3;
>             if (ty->msgtl_header.msgt_inline)
>               {
>                 /* Calculate length of data in bytes.  */
> -               const vm_size_t length = ((number * size) + 7) >> 3;
> -               clean_ports ((void *) ty, 0);
> +               clean_ports_and_memory (data, length, 0);
>                 /* Move to the next argument.  */
> -               ty = (void *) PTR_ALIGN_UP ((char *) ty + length,
> -                   __alignof__ (uintptr_t));
> +               ty = (void *) PTR_ALIGN_UP (data + length, __alignof__ 
> (uintptr_t));
>               }
>             else
>               {
> -               clean_ports (*(void **) ty,
> +               clean_ports_and_memory (*(void **) data, length,
>                              ty->msgtl_header.msgt_deallocate);
> -               ty = (void *) ty + sizeof (void *);
> +               ty = (void *) data + sizeof (void *);
>               }
>           }
>  #else  /* Untyped Mach IPC flavor. */
> -- 
> 2.39.2
> 

-- 
Samuel
---
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