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 and return -EINVAL if the value is out of bounds. Additionally, use 1U to prevent signed integer overflow when calculating eeprom_wc. Reported-by: [email protected] Tested-by: [email protected] Closes: https://syzkaller.appspot.com/bug?extid=e0abb1d45ac291ebebeb Signed-off-by: Yalagada Pavan Kumar <[email protected]> --- Tested using syzbot c reproducer. --- drivers/net/ethernet/intel/e100.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/e100.c b/drivers/net/ethernet/intel/e100.c index 29960762e64a..1de5cd41ea0c 100644 --- a/drivers/net/ethernet/intel/e100.c +++ b/drivers/net/ethernet/intel/e100.c @@ -744,7 +744,12 @@ static __le16 e100_eeprom_read(struct nic *nic, u16 *addr_len, u16 addr) * complete address. Use this to adjust addr_len. */ ctrl = ioread8(&nic->csr->eeprom_ctrl_lo); if (!(ctrl & eedo) && i > 16) { - *addr_len -= (i - 16); + u16 len = i - 16; + + if (len > *addr_len) + *addr_len = 0; + else + *addr_len -= len; i = 17; } @@ -765,7 +770,15 @@ static int e100_eeprom_load(struct nic *nic) /* Try reading with an 8-bit addr len to discover actual addr len */ e100_eeprom_read(nic, &addr_len, 0); - nic->eeprom_wc = 1 << addr_len; + + if (!addr_len || addr_len >= 16) { + netif_err(nic, probe, nic->netdev, + "Invalid EEPROM address length %u\n", + addr_len); + return -EINVAL; + } + + nic->eeprom_wc = 1U << addr_len; for (addr = 0; addr < nic->eeprom_wc; addr++) { nic->eeprom[addr] = e100_eeprom_read(nic, &addr_len, addr); -- 2.43.0
