[13/22] liquidio: fix possible eeprom format string overflow

Message ID 20170714120720.906842-14-arnd@arndb.de
State Accepted
Commit 56c0da495a0b38f8ac0c0c0e3fcc750ea449daea
Headers show
Series
  • gcc-7 -Wformat-* warnings
Related show

Commit Message

Arnd Bergmann July 14, 2017, 12:07 p.m.
gcc reports that the temporary buffer for computing the
string length may be too small here:

drivers/net/ethernet/cavium/liquidio/lio_ethtool.c: In function 'lio_get_eeprom_len':
/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c:345:21: error: 'sprintf' may write a terminating nul past the end of the destination [-Werror=format-overflow=]
  len = sprintf(buf, "boardname:%s serialnum:%s maj:%lld min:%lld\n",
                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/cavium/liquidio/lio_ethtool.c:345:6: note: 'sprintf' output between 35 and 167 bytes into a destination of size 128
  len = sprintf(buf, "boardname:%s serialnum:%s maj:%lld min:%lld\n",

This extends it to 192 bytes, which is certainly enough. As far
as I could tell, there are no other constraints that require a specific
maximum size.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 drivers/net/ethernet/cavium/liquidio/lio_ethtool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.9.0

Comments

David Miller July 14, 2017, 4:04 p.m. | #1
From: Arnd Bergmann <arnd@arndb.de>

Date: Fri, 14 Jul 2017 14:07:05 +0200

> gcc reports that the temporary buffer for computing the

> string length may be too small here:

> 

> drivers/net/ethernet/cavium/liquidio/lio_ethtool.c: In function 'lio_get_eeprom_len':

> /drivers/net/ethernet/cavium/liquidio/lio_ethtool.c:345:21: error: 'sprintf' may write a terminating nul past the end of the destination [-Werror=format-overflow=]

>   len = sprintf(buf, "boardname:%s serialnum:%s maj:%lld min:%lld\n",

>                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

> drivers/net/ethernet/cavium/liquidio/lio_ethtool.c:345:6: note: 'sprintf' output between 35 and 167 bytes into a destination of size 128

>   len = sprintf(buf, "boardname:%s serialnum:%s maj:%lld min:%lld\n",

> 

> This extends it to 192 bytes, which is certainly enough. As far

> as I could tell, there are no other constraints that require a specific

> maximum size.

> 

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>


Applied.

Patch

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c b/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c
index 28ecda3d3404..ebd353bc78ff 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c
@@ -335,7 +335,7 @@  lio_ethtool_get_channels(struct net_device *dev,
 
 static int lio_get_eeprom_len(struct net_device *netdev)
 {
-	u8 buf[128];
+	u8 buf[192];
 	struct lio *lio = GET_LIO(netdev);
 	struct octeon_device *oct_dev = lio->oct_dev;
 	struct octeon_board_info *board_info;