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authorSven Eckelmann <sven@narfation.org>2015-06-21 20:40:09 +0300
committerAntonio Quartulli <antonio@meshcoding.com>2015-08-25 01:12:22 +0300
commit0b8336f5fc26f263821534d7a9a3633748692207 (patch)
tree54e85d0494e92dc8ac92027b2c116ba1107b9fa8 /net/batman-adv/gateway_common.c
parent77927b7d9dd6c9c5f59f0f49c76cda54b908090e (diff)
downloadlinux-0b8336f5fc26f263821534d7a9a3633748692207.tar.xz
batman-adv: Fix gw_bandwidth calculation on 32 bit systems
The TVLV for the gw_bandwidth stores everything as u32. But the gw_bandwidth reads the signed long which limits the maximum value to (2 ** 31 - 1) on systems with 4 byte long. Also the input value is always converted from either Mibit/s or Kibit/s to 100Kibit/s. This reduces the values even further when the user sets it via the default unit Kibit/s. It may even cause an integer overflow and end up with a value the user never intended. Instead read the values as u64, check for possible overflows, do the unit adjustments and then reduce the size to u32. Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Diffstat (limited to 'net/batman-adv/gateway_common.c')
-rw-r--r--net/batman-adv/gateway_common.c49
1 files changed, 42 insertions, 7 deletions
diff --git a/net/batman-adv/gateway_common.c b/net/batman-adv/gateway_common.c
index 6b930a651f38..0cb5e6b6f6d4 100644
--- a/net/batman-adv/gateway_common.c
+++ b/net/batman-adv/gateway_common.c
@@ -22,6 +22,7 @@
#include <linux/errno.h>
#include <linux/byteorder/generic.h>
#include <linux/kernel.h>
+#include <linux/math64.h>
#include <linux/netdevice.h>
#include <linux/stddef.h>
#include <linux/string.h>
@@ -44,7 +45,7 @@ static bool batadv_parse_gw_bandwidth(struct net_device *net_dev, char *buff,
{
enum batadv_bandwidth_units bw_unit_type = BATADV_BW_UNIT_KBIT;
char *slash_ptr, *tmp_ptr;
- long ldown, lup;
+ u64 ldown, lup;
int ret;
slash_ptr = strchr(buff, '/');
@@ -62,7 +63,7 @@ static bool batadv_parse_gw_bandwidth(struct net_device *net_dev, char *buff,
*tmp_ptr = '\0';
}
- ret = kstrtol(buff, 10, &ldown);
+ ret = kstrtou64(buff, 10, &ldown);
if (ret) {
batadv_err(net_dev,
"Download speed of gateway mode invalid: %s\n",
@@ -72,14 +73,31 @@ static bool batadv_parse_gw_bandwidth(struct net_device *net_dev, char *buff,
switch (bw_unit_type) {
case BATADV_BW_UNIT_MBIT:
- *down = ldown * 10;
+ /* prevent overflow */
+ if (U64_MAX / 10 < ldown) {
+ batadv_err(net_dev,
+ "Download speed of gateway mode too large: %s\n",
+ buff);
+ return false;
+ }
+
+ ldown *= 10;
break;
case BATADV_BW_UNIT_KBIT:
default:
- *down = ldown / 100;
+ ldown = div_u64(ldown, 100);
break;
}
+ if (U32_MAX < ldown) {
+ batadv_err(net_dev,
+ "Download speed of gateway mode too large: %s\n",
+ buff);
+ return false;
+ }
+
+ *down = ldown;
+
/* we also got some upload info */
if (slash_ptr) {
bw_unit_type = BATADV_BW_UNIT_KBIT;
@@ -95,7 +113,7 @@ static bool batadv_parse_gw_bandwidth(struct net_device *net_dev, char *buff,
*tmp_ptr = '\0';
}
- ret = kstrtol(slash_ptr + 1, 10, &lup);
+ ret = kstrtou64(slash_ptr + 1, 10, &lup);
if (ret) {
batadv_err(net_dev,
"Upload speed of gateway mode invalid: %s\n",
@@ -105,13 +123,30 @@ static bool batadv_parse_gw_bandwidth(struct net_device *net_dev, char *buff,
switch (bw_unit_type) {
case BATADV_BW_UNIT_MBIT:
- *up = lup * 10;
+ /* prevent overflow */
+ if (U64_MAX / 10 < lup) {
+ batadv_err(net_dev,
+ "Upload speed of gateway mode too large: %s\n",
+ slash_ptr + 1);
+ return false;
+ }
+
+ lup *= 10;
break;
case BATADV_BW_UNIT_KBIT:
default:
- *up = lup / 100;
+ lup = div_u64(lup, 100);
break;
}
+
+ if (U32_MAX < lup) {
+ batadv_err(net_dev,
+ "Upload speed of gateway mode too large: %s\n",
+ slash_ptr + 1);
+ return false;
+ }
+
+ *up = lup;
}
return true;