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

[Tom Rini]

On Mon, Apr 12, 2021 at 12:25:32AM +0200, Heinrich Schuchardt wrote:

> 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.

A useful analysis in case anyone brings these boards back.  I'm about to
push the series that delete this due to lack of migration.

-- 
Tom
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