> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf
> Of [email protected]
> Sent: Monday, August 10, 2026 10:34 AM
> To: Nguyen, Anthony L <[email protected]>; Kitszel,
> Przemyslaw <[email protected]>
> Cc: [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected];
> [email protected]; Yalagada Pavan
> Kumar <[email protected]>
> Subject: [Intel-wired-lan] [PATCH v2] e100: prevent shift-out-of-
> bounds in e100_eeprom_load()
>
> From: Yalagada Pavan Kumar <[email protected]>
>
> When reading the EEPROM address length, e100_eeprom_read() can return
> an invalid length (0 or >= 16). Passing an invalid addr_len to bit-
> shift operations causes a shift out-of-bounds, triggering a kernel
> panic or UBSAN warning.
>
> Validate addr_len after reading it from EEPROM in both
> e100_eeprom_load() and e100_eeprom_save(), and return -EIO if the
> value is out of bounds.
>
> Reported-by: [email protected]
> Closes: https://syzkaller.appspot.com/bug?extid=e0abb1d45ac291ebebeb
> Signed-off-by: Yalagada Pavan Kumar <[email protected]>
> ---
> Tested in QEMU using syzbot c reproducer.
>
> v2:
> - Return -EIO instead of -EINVAL for an invalid EEPROM address length.
> - Validate addr_len in e100_eeprom_save() as well.
> - Drop the unnecessary 1U change in the shift.
> - Update the commit message.
>
> v1:
> https://lore.kernel.org/all/20260807145626.52692-1-
> [email protected]/T/
> ---
> drivers/net/ethernet/intel/e100.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/e100.c
> b/drivers/net/ethernet/intel/e100.c
> index 1de5cd41ea0c..464dc2d6cdb5 100644
> --- a/drivers/net/ethernet/intel/e100.c
> +++ b/drivers/net/ethernet/intel/e100.c
> @@ -775,10 +775,10 @@ static int e100_eeprom_load(struct nic *nic)
> netif_err(nic, probe, nic->netdev,
> "Invalid EEPROM address length %u\n",
> addr_len);
> - return -EINVAL;
> + return -EIO;
> }
>
> - nic->eeprom_wc = 1U << addr_len;
> + nic->eeprom_wc = 1 << addr_len;
Why do you drop U suffix? For me it looks like you trade one warning for
another.
I'm for explicit (u16)BIT(addr_len), what do you think?
>
> for (addr = 0; addr < nic->eeprom_wc; addr++) {
> nic->eeprom[addr] = e100_eeprom_read(nic, &addr_len,
> addr); @@ -804,6 +804,14 @@ static int e100_eeprom_save(struct nic
> *nic, u16 start, u16 count)
>
> /* Try reading with an 8-bit addr len to discover actual addr
> len */
> e100_eeprom_read(nic, &addr_len, 0);
> +
> + if (!addr_len || addr_len >= 16) {
> + netif_err(nic, probe, nic->netdev,
> + "Invalid EEPROM address length %u\n",
> + addr_len);
> + return -EIO;
> + }
> +
> nic->eeprom_wc = 1 << addr_len;
I'm for explicit (u16)BIT(addr_len) here too, what do you think?
>
> if (start + count >= nic->eeprom_wc)
> --
> 2.43.0
