[lvc-project] [PATCH net 2/3] e1000: fix endianness conversion of uninitialized words

[Tony Nguyen]

On 3/18/2026 5:05 AM, Agalakov Daniil wrote:
> [Why]
> In e1000_set_eeprom(), the eeprom_buff is allocated to hold a range of
> words. However, only the boundary words (the first and the last) are
> populated from the EEPROM if the write request is not word-aligned.
> The words in the middle of the buffer remain uninitialized because they
> are intended to be completely overwritten by the new data via memcpy().
> 
> The previous implementation had a loop that performed le16_to_cpus()
> on the entire buffer. This resulted in endianness conversion being
> performed on uninitialized memory for all interior words.
> 
> Fix this by converting the endianness only for the boundary words
> immediately after they are successfully read from the EEPROM.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

While this is definitely better, I'm not sure there's a bug here since 
it's being immediately overwritten. Seems like this patch would be 
better going to *-next as an improvement.

Thanks,
Tony

> Co-developed-by: Iskhakov Daniil <dish at amicon.ru>
> Signed-off-by: Iskhakov Daniil <dish at amicon.ru>
> Signed-off-by: Agalakov Daniil <ade at amicon.ru>
> ---
>   drivers/net/ethernet/intel/e1000/e1000_ethtool.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> index 4dcbeabb3ad2..c15ad95c63c1 100644
> --- a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> +++ b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> @@ -499,6 +499,9 @@ static int e1000_set_eeprom(struct net_device *netdev,
>   		if (ret_val)
>   			goto out;
>   
> +		/* Device's eeprom is always little-endian, word addressable */
> +		le16_to_cpus(&eeprom_buff[0]);
> +
>   		ptr++;
>   	}
>   	if ((eeprom->offset + eeprom->len) & 1) {
> @@ -509,11 +512,10 @@ static int e1000_set_eeprom(struct net_device *netdev,
>   					    &eeprom_buff[last_word - first_word]);
>   		if (ret_val)
>   			goto out;
> -	}
>   
> -	/* Device's eeprom is always little-endian, word addressable */
> -	for (i = 0; i < last_word - first_word + 1; i++)
> -		le16_to_cpus(&eeprom_buff[i]);
> +		/* Device's eeprom is always little-endian, word addressable */
> +		le16_to_cpus(&eeprom_buff[last_word - first_word]);
> +	}
>   
>   	memcpy(ptr, bytes, eeprom->len);
>