[BUG][Cyrus BOARD] out of bound access in board/varisys/common/sys_eeprom.c

[Heinrich Schuchardt]

Hello Andy,

in the code of your patch "mpc85xx: Add support for the Varisys Cyrus
board" merged in 2015 as 87e29878cab an out of bound access occurs. See
below.

On 11/4/15 10:48 PM, Andy Fleming wrote:
> This board runs a P5020 or P5040 chip, and utilizes
> an EEPROM with similar formatting to the Freescale P5020DS.
>
> Large amounts of this code were developed by
> Adrian Cox <adrian at humboldt dot co dot uk>
>
> Signed-off-by: Andy Fleming <afleming at gmail.com>
> Reviewed-by: York Sun <yorksun at freescale.com>
> ---

<snip />

 > +++ b/board/varisys/common/sys_eeprom.c

<snip />

 > +static struct __attribute__ ((__packed__)) eeprom {
 > +	u8 id[4];         /* 0x00 - 0x03 EEPROM Tag 'NXID' */
 > +	u8 sn[12];        /* 0x04 - 0x0F Serial Number */
 > +	u8 errata[5];     /* 0x10 - 0x14 Errata Level */
 > +	u8 date[6];       /* 0x15 - 0x1a Build Date */
 > +	u8 res_0;         /* 0x1b        Reserved */
 > +	u32 version;      /* 0x1c - 0x1f NXID Version */
 > +	u8 tempcal[8];    /* 0x20 - 0x27 Temperature Calibration Factors */
 > +	u8 tempcalsys[2]; /* 0x28 - 0x29 System Temperature Calibration
Factors */
 > +	u8 tempcalflags;  /* 0x2a        Temperature Calibration Flags */
 > +	u8 res_1[21];     /* 0x2b - 0x3f Reserved */
 > +	u8 mac_count;     /* 0x40        Number of MAC addresses */
 > +	u8 mac_flag;      /* 0x41        MAC table flags */
 > +	u8 mac[MAX_NUM_PORTS][6];     /* 0x42 - x MAC addresses */
 > +	u32 crc;          /* x+1         CRC32 checksum */
 > +} e;

<snip /> // MAX_NUM_PORTS = 8

> +int mac_read_from_eeprom_common(void)
> +{
> +	unsigned int i;
> +	u32 crc, crc_offset = offsetof(struct eeprom, crc);
> +	u32 *crcp; /* Pointer to the CRC in the data read from the EEPROM */
> +
> +	puts("EEPROM: ");
> +
> +	if (read_eeprom()) {
> +		printf("Read failed.\n");
> +		return 0;
> +	}
> +
> +	if (!is_valid) {
> +		printf("Invalid ID (%02x %02x %02x %02x)\n",
> +		       e.id[0], e.id[1], e.id[2], e.id[3]);
> +		return 0;
> +	}
> +
> +	crc = crc32(0, (void *)&e, crc_offset);
> +	crcp = (void *)&e + crc_offset;
> +	if (crc != be32_to_cpu(*crcp)) {
> +		printf("CRC mismatch (%08x != %08x)\n", crc,
> +			be32_to_cpu(e.crc));
> +		return 0;
> +	}
> +
> +	/*
> +	 * MAC address #9 in v1 occupies the same position as the CRC in v0.
> +	 * Erase it so that it's not mistaken for a MAC address.  We'll
> +	 * update the CRC later.
> +	 */
> +	if (e.version == 0)
> +		memset(e.mac[8], 0xff, 6);

Here you are writing 2 bytes beyond the size of e.

Best regards

Heinrich