[patch 077/232] sdio: fix read buffer overflow

[Jonathan Cameron]

Hi All,

This patch is causing a regression with libertas 8686.
It's only finding 3 strings which I'm guessing means
it is an invalid CISTPL_VERS_1. Unfortunately the libertas_sdio
code relies on a string in one of them to tell it what model of
card we have.

Can someone confirm what the CIS_VERS_1 spec actually is?
I've found one vague reference to entries 3 and 4 being optional
but the simplified sdio spec refers to the pcmcia 3.2.10 spec
which I don't have easy access to.

Any suggestions on a work around?

Thanks,

Jonathan


> From: Roel Kluin <roel.kluin at gmail.com>
> 
> Avoid buffer underrun when parsing an invalid CISTPL_VERS_1.
> 
> Signed-off-by: Roel Kluin <roel.kluin at gmail.com>
> Cc: David Vrabel <david.vrabel at csr.com>
> Cc: <linux-mmc at vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> ---
> 
>  drivers/mmc/core/sdio_cis.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff -puN drivers/mmc/core/sdio_cis.c~sdio-fix-read-buffer-overflow drivers/mmc/core/sdio_cis.c
> --- a/drivers/mmc/core/sdio_cis.c~sdio-fix-read-buffer-overflow
> +++ a/drivers/mmc/core/sdio_cis.c
> @@ -40,7 +40,7 @@ static int cistpl_vers_1(struct mmc_card
>  			nr_strings++;
>  	}
>  
> -	if (buf[i-1] != '\0') {
> +	if (nr_strings < 4) {
>  		printk(KERN_WARNING "SDIO: ignoring broken CISTPL_VERS_1\n");
>  		return 0;
>  	}
> _
> --
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