Re: [Qemu-devel] [PATCH v2 3/9] ccid-card-passthru: Assert on a stricter expression

[Marc-André Lureau]

Hi

On Thu, Feb 14, 2019 at 9:20 PM Philippe Mathieu-Daudé
 wrote:
>
> Suggested-by: Paolo Bonzini 
> Signed-off-by: Philippe Mathieu-Daudé 
> ---
>  hw/usb/ccid-card-passthru.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/usb/ccid-card-passthru.c b/hw/usb/ccid-card-passthru.c
> index 1676b5fc05..0c44b38fc2 100644
> --- a/hw/usb/ccid-card-passthru.c
> +++ b/hw/usb/ccid-card-passthru.c
> @@ -270,7 +270,7 @@ static void ccid_card_vscard_read(void *opaque, const 
> uint8_t *buf, int size)
>  VSCMsgHeader *hdr;
>
>  assert(size <= VSCARD_IN_SIZE - card->vscard_in_pos);
> -assert(card->vscard_in_hdr < VSCARD_IN_SIZE);
> +assert(card->vscard_in_hdr < card->vscard_in_pos);


I think you need "<=".

card->vscard_in_hdr is updated in the loop and may reach card->vscard_in_pos:

while ((card->vscard_in_pos - card->vscard_in_hdr >= sizeof(VSCMsgHeader))
 &&(card->vscard_in_pos - card->vscard_in_hdr >=
  sizeof(VSCMsgHeader) + ntohl(hdr->length))) {
...
card->vscard_in_hdr += hdr->length + sizeof(VSCMsgHeader);
...
}

if "hdr->length + sizeof(VSCMsgHeader)" == "card->vscard_in_pos -
card->vscard_in_hdr", card->vscard_in_hdr == card->vscard_in_pos after
the loop.


I think the existing assert() could also stay.

>  memcpy(card->vscard_in_data + card->vscard_in_pos, buf, size);
>  card->vscard_in_pos += size;
>  hdr = (VSCMsgHeader *)(card->vscard_in_data + card->vscard_in_hdr);
> --
> 2.20.1
>

Re: [Qemu-devel] [PATCH v2 3/9] ccid-card-passthru: Assert on a stricter expression

[Wei Yang]

Would it be better to have some description?

On Thu, Feb 14, 2019 at 09:19:33PM +0100, Philippe Mathieu-Daudé wrote:
>Suggested-by: Paolo Bonzini 
>Signed-off-by: Philippe Mathieu-Daudé 
>---
> hw/usb/ccid-card-passthru.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/hw/usb/ccid-card-passthru.c b/hw/usb/ccid-card-passthru.c
>index 1676b5fc05..0c44b38fc2 100644
>--- a/hw/usb/ccid-card-passthru.c
>+++ b/hw/usb/ccid-card-passthru.c
>@@ -270,7 +270,7 @@ static void ccid_card_vscard_read(void *opaque, const 
>uint8_t *buf, int size)
> VSCMsgHeader *hdr;
> 
> assert(size <= VSCARD_IN_SIZE - card->vscard_in_pos);
>-assert(card->vscard_in_hdr < VSCARD_IN_SIZE);
>+assert(card->vscard_in_hdr < card->vscard_in_pos);
> memcpy(card->vscard_in_data + card->vscard_in_pos, buf, size);
> card->vscard_in_pos += size;
> hdr = (VSCMsgHeader *)(card->vscard_in_data + card->vscard_in_hdr);
>-- 
>2.20.1
>

-- 
Wei Yang
Help you, Help me

[Qemu-devel] [PATCH v2 3/9] ccid-card-passthru: Assert on a stricter expression

[Philippe Mathieu-Daudé]

Suggested-by: Paolo Bonzini 
Signed-off-by: Philippe Mathieu-Daudé 
---
 hw/usb/ccid-card-passthru.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/usb/ccid-card-passthru.c b/hw/usb/ccid-card-passthru.c
index 1676b5fc05..0c44b38fc2 100644
--- a/hw/usb/ccid-card-passthru.c
+++ b/hw/usb/ccid-card-passthru.c
@@ -270,7 +270,7 @@ static void ccid_card_vscard_read(void *opaque, const 
uint8_t *buf, int size)
 VSCMsgHeader *hdr;
 
 assert(size <= VSCARD_IN_SIZE - card->vscard_in_pos);
-assert(card->vscard_in_hdr < VSCARD_IN_SIZE);
+assert(card->vscard_in_hdr < card->vscard_in_pos);
 memcpy(card->vscard_in_data + card->vscard_in_pos, buf, size);
 card->vscard_in_pos += size;
 hdr = (VSCMsgHeader *)(card->vscard_in_data + card->vscard_in_hdr);
-- 
2.20.1