e100_eeprom_load() and e100_eeprom_save() start with an address length
of 8 and call e100_eeprom_read() to auto-detect the real EEPROM address
length. e100_eeprom_read() adjusts the length with
*addr_len -= (i - 16);
based on when the EEPROM drives a dummy zero onto EEDO. A malfunctioning
or emulated device that drives EEDO low too early makes (i - 16) exceed
the current length, underflowing the u16 addr_len to a large value such
as 65529.
That value is then used as a shift count:
nic->eeprom_wc = 1 << addr_len;
which is undefined behaviour and additionally overflows the fixed-size
nic->eeprom[256] cache.
UBSAN: shift-out-of-bounds in drivers/net/ethernet/intel/e100.c:768:21
shift exponent 65529 is too large for 32-bit type 'int'
The EEPROM cache holds at most 256 words, so a valid address length is
never larger than 8. Reject larger values before using addr_len.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=e0abb1d45ac291ebebeb
Signed-off-by: Malathi <[email protected]>
---
drivers/net/ethernet/intel/e100.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/net/ethernet/intel/e100.c
b/drivers/net/ethernet/intel/e100.c
index 29960762e64a..a236273f5e65 100644
--- a/drivers/net/ethernet/intel/e100.c
+++ b/drivers/net/ethernet/intel/e100.c
@@ -765,6 +765,11 @@ 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);
+ if (addr_len > 8) {
+ netif_err(nic, probe, nic->netdev,
+ "invalid EEPROM address length %u\n", addr_len);
+ return -EINVAL;
+ }
nic->eeprom_wc = 1 << addr_len;
for (addr = 0; addr < nic->eeprom_wc; addr++) {
@@ -791,6 +796,11 @@ 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 > 8) {
+ netif_err(nic, probe, nic->netdev,
+ "invalid EEPROM address length %u\n", addr_len);
+ return -EINVAL;
+ }
nic->eeprom_wc = 1 << addr_len;
if (start + count >= nic->eeprom_wc)
--
2.43.0
