Re: [Intel-wired-lan] [PATCH net-next v2 1/2] e1000: limit endianness conversion to boundary words

Loktionov, Aleksandr
2026-03-26T07:29:17Z

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
> Of Agalakov Daniil
> Sent: Wednesday, March 25, 2026 4:16 PM
> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>
> Cc: Agalakov Daniil <ade@amicon.ru>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@intel.com>; Andrew Lunn <andrew+netdev@lunn.ch>;
> David S. Miller <davem@davemloft.net>; Eric Dumazet
> <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni
> <pabeni@redhat.com>; intel-wired-lan@lists.osuosl.org;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; lvc-
> project@linuxtesting.org; Daniil Iskhakov <dish@amicon.ru>; Roman
> Razov <rrv@amicon.ru>
> Subject: [Intel-wired-lan] [PATCH net-next v2 1/2] e1000: limit
> endianness conversion to boundary words
>
> [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.
>
> Co-developed-by: Iskhakov Daniil <dish@amicon.ru>
> Signed-off-by: Iskhakov Daniil <dish@amicon.ru>
> Signed-off-by: Agalakov Daniil <ade@amicon.ru>
> ---
> v2:
> - Split from the original bugfix series and targeted at 'net-text'.
> - Removed the Fixes: tag; limiting the conversion scope is an
> improvement to avoid unnecessary processing of uninitialized
> memory.
> - Improved commit description for clarity.
>
> drivers/net/ethernet/intel/e1000/e1000_ethtool.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> index ab232b3fbbd0..38b1f91823ef 100644
> --- a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> +++ b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> @@ -496,6 +496,10 @@ static int e1000_set_eeprom(struct net_device
> *netdev,
> */
> ret_val = e1000_read_eeprom(hw, first_word, 1,
> &eeprom_buff[0]);
> +
> + /* Device's eeprom is always little-endian, word
> addressable */
> + le16_to_cpus(&eeprom_buff[0]);
> +
> ptr++;
> }
> if (((eeprom->offset + eeprom->len) & 1) && (ret_val == 0)) {
> @@ -504,11 +508,10 @@ static int e1000_set_eeprom(struct net_device
> *netdev,
> */
> ret_val = e1000_read_eeprom(hw, last_word, 1,
> &eeprom_buff[last_word -
> first_word]);
> - }
>
> - /* 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);
>
> --
> 2.51.0

e1000e: limit endianness conversion to boundary words