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| author | Sven Eckelmann <sven@narfation.org> | 2015-06-21 19:40:09 +0200 |
|---|---|---|
| committer | Antonio Quartulli <antonio@meshcoding.com> | 2015-08-25 00:12:22 +0200 |
| commit | 0b8336f5fc26f263821534d7a9a3633748692207 (patch) | |
| tree | 54e85d0494e92dc8ac92027b2c116ba1107b9fa8 /net/batman-adv | |
| parent | 77927b7d9dd6c9c5f59f0f49c76cda54b908090e (diff) | |
| download | lwn-0b8336f5fc26f263821534d7a9a3633748692207.tar.gz lwn-0b8336f5fc26f263821534d7a9a3633748692207.zip | |
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')
| -rw-r--r-- | net/batman-adv/gateway_common.c | 49 |
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; |