Re: [PATCH] habv4: Fix parsing of unresonable events.

[Sascha Hauer <sha@pengutronix.de>]

On Mon, Dec 18, 2023 at 09:25:44PM +0100, Christian Melki wrote:
> An unknown root cause made data look like events (0xdb)
> with very long event lengths. This was causing
> very long printouts of bogus stuff in the console.
> 
> While the root cause needs to be found and fixed,
> there is no need of parsing events with abnormal lengths.
> Also stop parsing if length exceeds the end of scope.
> 
> Signed-off-by: Christian Melki <christian.melki@t2data.com>
> ---
>  drivers/hab/habv4.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/hab/habv4.c b/drivers/hab/habv4.c
> index f74de009fc..1a55a3e448 100644
> --- a/drivers/hab/habv4.c
> +++ b/drivers/hab/habv4.c
> @@ -203,6 +203,8 @@ static uint32_t hab_sip_get_version(void)
>  	return (uint32_t)res.a0;
>  }
>  
> +#define HABV4_EVENT_MAX_LEN		0x80
> +
>  #define IMX8MQ_ROM_OCRAM_ADDRESS	0x9061C0
>  #define IMX8MM_ROM_OCRAM_ADDRESS	0x908040
>  #define IMX8MN_ROM_OCRAM_ADDRESS	0x908040
> @@ -217,6 +219,7 @@ static enum hab_status imx8m_read_sram_events(enum hab_status status,
>  	char *sram;
>  	int i = 0;
>  	int internal_index = 0;
> +	uint16_t ev_len;
>  	char *end = 0;
>  	struct hab_event_record *search;
>  
> @@ -236,13 +239,21 @@ static enum hab_status imx8m_read_sram_events(enum hab_status status,
>  	 * recommends the address and size, however errors are usually contained
>  	 * within the first bytes. Scan only the first few bytes to rule out
>  	 * lots of false positives.
> +	 * The max event length is just a sanity check.
>  	 */
> -	end = sram +  0x1a0;
> +	end = sram + 0x1a0;
>  
>  	while (sram < end) {
>  		if (*sram == 0xdb) {
>  			search = (void *)sram;
> -			sram = sram + be16_to_cpu(search->hdr.len);
> +			ev_len = be16_to_cpu(search->hdr.len);
> +			if (ev_len > HABV4_EVENT_MAX_LEN) {
> +				break;
> +			}
> +			sram += ev_len;
> +			if (sram > end) {
> +				break;
> +			}
>  			events[num_events] = search;
>  			num_events++;
>  		} else {
> -- 
> 2.34.1
> 
> 
> 

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