Re: [Qemu-devel] [PATCH v2] bt: use size_t type for length parameters instead of int

[Hugo Lefeuvre <hle@debian.org>]

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Hi,

> The length parameter values are not negative, thus use an unsigned
> type 'size_t' for them. Many routines pass 'len' values to memcpy(3)
> calls. If it was negative, it could lead to memory corruption issues.
> Add check to avoid it.

I'm working on a Debian LTS security update for qemu and am currently
thinking about addressing this issue as well.

I see this patch has not been applied yet and the bluetooth subsystem
is pending deprecation. Are you still considering to apply it?

> @@ -113,6 +113,7 @@ static void vhci_host_send(void *opaque,
>      static uint8_t buf[4096];
>  
>      buf[0] = type;
> +    assert(len < sizeof(buf));
>      memcpy(buf + 1, data, len);
>  
>      while (write(s->fd, buf, len + 1) < 0)

Any reason why assert() calls are used here ?

These checks should always be executed, but they won't if user compiles
without asserts. Also, AFAIK any assert failure will stop the qemu host
process which is not what we want in this case.

regards,
 Hugo

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                Hugo Lefeuvre (hle)    |    www.owl.eu.com
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