Re: [PATCH v2] fsl/fman: Validate cell-index value obtained from Device Tree

[Sean Anderson <sean.anderson@seco.com>]

On 7/2/24 10:01, Aleksandr Mishin wrote:
> [You don't often get email from amishin@t-argos.ru. Learn why this is important at https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2faka.ms%2fLearnAboutSenderIdentification&umid=ca782a5b-a3fd-4738-b50c-ffbd8e52e50f&auth=d807158c60b7d2502abde8a2fc01f40662980862-ac0deac714bbe85d389fd2711a17d0113034b3ca ]
>
> Cell-index value is obtained from Device Tree and then used to calculate
> the index for accessing arrays port_mfl[], mac_mfl[] and intr_mng[].
> In case of broken DT due to any error cell-index can contain any value
> and it is possible to go beyond the array boundaries which can lead
> at least to memory corruption.
> Validate cell-index value obtained from Device Tree.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 414fd46e7762 ("fsl/fman: Add FMan support")
> Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
> ---
> v1->v2: Move check to mac.c to avoid allmodconfig build errors and reference leaks
>
>  drivers/net/ethernet/freescale/fman/fman.c | 1 -
>  drivers/net/ethernet/freescale/fman/fman.h | 3 +++
>  drivers/net/ethernet/freescale/fman/mac.c  | 4 ++++
>  3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/freescale/fman/fman.c b/drivers/net/ethernet/freescale/fman/fman.c
> index d96028f01770..fb416d60dcd7 100644
> --- a/drivers/net/ethernet/freescale/fman/fman.c
> +++ b/drivers/net/ethernet/freescale/fman/fman.c
> @@ -24,7 +24,6 @@
>
>  /* General defines */
>  #define FMAN_LIODN_TBL                 64      /* size of LIODN table */
> -#define MAX_NUM_OF_MACS                        10
>  #define FM_NUM_OF_FMAN_CTRL_EVENT_REGS 4
>  #define BASE_RX_PORTID                 0x08
>  #define BASE_TX_PORTID                 0x28
> diff --git a/drivers/net/ethernet/freescale/fman/fman.h b/drivers/net/ethernet/freescale/fman/fman.h
> index 2ea575a46675..74eb62eba0d7 100644
> --- a/drivers/net/ethernet/freescale/fman/fman.h
> +++ b/drivers/net/ethernet/freescale/fman/fman.h
> @@ -74,6 +74,9 @@
>  #define BM_MAX_NUM_OF_POOLS            64 /* Buffers pools */
>  #define FMAN_PORT_MAX_EXT_POOLS_NUM    8  /* External BM pools per Rx port */
>
> +/* General defines */
> +#define MAX_NUM_OF_MACS                        10
> +
>  struct fman; /* FMan data */
>
>  /* Enum for defining port types */
> diff --git a/drivers/net/ethernet/freescale/fman/mac.c b/drivers/net/ethernet/freescale/fman/mac.c
> index 9767586b4eb3..ac9ad5e67b44 100644
> --- a/drivers/net/ethernet/freescale/fman/mac.c
> +++ b/drivers/net/ethernet/freescale/fman/mac.c
> @@ -247,6 +247,10 @@ static int mac_probe(struct platform_device *_of_dev)
>                 dev_err(dev, "failed to read cell-index for %pOF\n", mac_node);
>                 return -EINVAL;
>         }
> +       if (val >= MAX_NUM_OF_MACS) {
> +               dev_err(dev, "cell-index value is too big for %pOF\n", mac_node);
> +               return -EINVAL;
> +       }
>         priv->cell_index = (u8)val;
>
>         /* Get the MAC address */
> --
> 2.30.2
>

Reviewed-by: Sean Anderson <sean.anderson@seco.com>

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