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authorWang Chen <wangchen@cn.fujitsu.com>2008-06-18 01:48:28 -0700
committerDavid S. Miller <davem@davemloft.net>2008-06-18 01:48:28 -0700
commitdad9b335c6940de2746a9788eb456d09cf102f81 (patch)
treec74092de70d7c2c9ba88bf580bc404133b55c490 /net/core
parentdd574dbfcc9e74e7dd8fd59ae0075d23e71a3da1 (diff)
netdevice: Fix promiscuity and allmulti overflow
Max of promiscuity and allmulti plus positive @inc can cause overflow. Fox example: when allmulti=0xFFFFFFFF, any caller give dev_set_allmulti() a positive @inc will cause allmulti be off. This is not what we want, though it's rare case. The fix is that only negative @inc will cause allmulti or promiscuity be off and when any caller makes the counters touch the roof, we return error. Change of v2: Change void function dev_set_promiscuity/allmulti to return int. So callers can get the overflow error. Caller's fix will be done later. Change of v3: 1. Since we return error to caller, we don't need to print KERN_ERROR, KERN_WARNING is enough. 2. In dev_set_promiscuity(), if __dev_set_promiscuity() failed, we return at once. Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/dev.c55
1 files changed, 45 insertions, 10 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 0e45742e715..a495f712d38 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2771,16 +2771,29 @@ int netdev_set_master(struct net_device *slave, struct net_device *master)
return 0;
}
-static void __dev_set_promiscuity(struct net_device *dev, int inc)
+static int __dev_set_promiscuity(struct net_device *dev, int inc)
{
unsigned short old_flags = dev->flags;
ASSERT_RTNL();
- if ((dev->promiscuity += inc) == 0)
- dev->flags &= ~IFF_PROMISC;
- else
- dev->flags |= IFF_PROMISC;
+ dev->flags |= IFF_PROMISC;
+ dev->promiscuity += inc;
+ if (dev->promiscuity == 0) {
+ /*
+ * Avoid overflow.
+ * If inc causes overflow, untouch promisc and return error.
+ */
+ if (inc < 0)
+ dev->flags &= ~IFF_PROMISC;
+ else {
+ dev->promiscuity -= inc;
+ printk(KERN_WARNING "%s: promiscuity touches roof, "
+ "set promiscuity failed, promiscuity feature "
+ "of device might be broken.\n", dev->name);
+ return -EOVERFLOW;
+ }
+ }
if (dev->flags != old_flags) {
printk(KERN_INFO "device %s %s promiscuous mode\n",
dev->name, (dev->flags & IFF_PROMISC) ? "entered" :
@@ -2798,6 +2811,7 @@ static void __dev_set_promiscuity(struct net_device *dev, int inc)
if (dev->change_rx_flags)
dev->change_rx_flags(dev, IFF_PROMISC);
}
+ return 0;
}
/**
@@ -2809,14 +2823,19 @@ static void __dev_set_promiscuity(struct net_device *dev, int inc)
* remains above zero the interface remains promiscuous. Once it hits zero
* the device reverts back to normal filtering operation. A negative inc
* value is used to drop promiscuity on the device.
+ * Return 0 if successful or a negative errno code on error.
*/
-void dev_set_promiscuity(struct net_device *dev, int inc)
+int dev_set_promiscuity(struct net_device *dev, int inc)
{
unsigned short old_flags = dev->flags;
+ int err;
- __dev_set_promiscuity(dev, inc);
+ err = __dev_set_promiscuity(dev, inc);
+ if (!err)
+ return err;
if (dev->flags != old_flags)
dev_set_rx_mode(dev);
+ return err;
}
/**
@@ -2829,22 +2848,38 @@ void dev_set_promiscuity(struct net_device *dev, int inc)
* to all interfaces. Once it hits zero the device reverts back to normal
* filtering operation. A negative @inc value is used to drop the counter
* when releasing a resource needing all multicasts.
+ * Return 0 if successful or a negative errno code on error.
*/
-void dev_set_allmulti(struct net_device *dev, int inc)
+int dev_set_allmulti(struct net_device *dev, int inc)
{
unsigned short old_flags = dev->flags;
ASSERT_RTNL();
dev->flags |= IFF_ALLMULTI;
- if ((dev->allmulti += inc) == 0)
- dev->flags &= ~IFF_ALLMULTI;
+ dev->allmulti += inc;
+ if (dev->allmulti == 0) {
+ /*
+ * Avoid overflow.
+ * If inc causes overflow, untouch allmulti and return error.
+ */
+ if (inc < 0)
+ dev->flags &= ~IFF_ALLMULTI;
+ else {
+ dev->allmulti -= inc;
+ printk(KERN_WARNING "%s: allmulti touches roof, "
+ "set allmulti failed, allmulti feature of "
+ "device might be broken.\n", dev->name);
+ return -EOVERFLOW;
+ }
+ }
if (dev->flags ^ old_flags) {
if (dev->change_rx_flags)
dev->change_rx_flags(dev, IFF_ALLMULTI);
dev_set_rx_mode(dev);
}
+ return 0;
}
/*