diff mbox

[net-next,v2] bonding: fix string comparison errors

Message ID 1311714479-9260-1-git-send-email-andy@greyhouse.net
State Superseded, archived
Delegated to: David Miller
Headers show

Commit Message

Andy Gospodarek July 26, 2011, 9:07 p.m. UTC
When a bond contains a device where one name is the subset of another
(eth1 and eth10, for example), one cannot properly set the primary
device or the currently active device.

This was reported and based on work by Takuma Umeya.  I also verified
the problem and tested that this fix resolves it.

V2: A few did not like the the current code or my changes, so I
re-factored bonding_store_primary and bonding_store_active_slave to be a
bit cleaner, dropped the use of strnicmp since we did not really need
the comparison to be case insensitive, and formatted the input string
from sysfs so a comparison to IFNAMSIZ could be used.

I also discovered an error in bonding_store_active_slave that would
modify bond->primary_slave rather than bond->curr_active_slave before
forcing the bonding driver to choose a new active slave.

Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Reported-by: Takuma Umeya <tumeya@redhat.com>

---
 drivers/net/bonding/bond_sysfs.c |  130 ++++++++++++++++++++------------------
 1 files changed, 68 insertions(+), 62 deletions(-)

Comments

Andy Gospodarek July 26, 2011, 9:08 p.m. UTC | #1
On Tue, Jul 26, 2011 at 05:07:59PM -0400, Andy Gospodarek wrote:
> When a bond contains a device where one name is the subset of another
> (eth1 and eth10, for example), one cannot properly set the primary
> device or the currently active device.
> 
> This was reported and based on work by Takuma Umeya.  I also verified
> the problem and tested that this fix resolves it.
> 
> V2: A few did not like the the current code or my changes, so I
> re-factored bonding_store_primary and bonding_store_active_slave to be a
> bit cleaner, dropped the use of strnicmp since we did not really need
> the comparison to be case insensitive, and formatted the input string
> from sysfs so a comparison to IFNAMSIZ could be used.
> 
> I also discovered an error in bonding_store_active_slave that would
> modify bond->primary_slave rather than bond->curr_active_slave before
> forcing the bonding driver to choose a new active slave.
> 

Sorry I apparently cannot properly use git send-email. :-)

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diff mbox

Patch

diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index b60835f..c178b1e 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1025,6 +1025,7 @@  static ssize_t bonding_store_primary(struct device *d,
 	int i;
 	struct slave *slave;
 	struct bonding *bond = to_bond(d);
+	char ifname[IFNAMSIZ];
 
 	if (!rtnl_trylock())
 		return restart_syscall();
@@ -1035,32 +1036,33 @@  static ssize_t bonding_store_primary(struct device *d,
 	if (!USES_PRIMARY(bond->params.mode)) {
 		pr_info("%s: Unable to set primary slave; %s is in mode %d\n",
 			bond->dev->name, bond->dev->name, bond->params.mode);
-	} else {
-		bond_for_each_slave(bond, slave, i) {
-			if (strnicmp
-			    (slave->dev->name, buf,
-			     strlen(slave->dev->name)) == 0) {
-				pr_info("%s: Setting %s as primary slave.\n",
-					bond->dev->name, slave->dev->name);
-				bond->primary_slave = slave;
-				strcpy(bond->params.primary, slave->dev->name);
-				bond_select_active_slave(bond);
-				goto out;
-			}
-		}
+		goto out;
+	}
 
-		/* if we got here, then we didn't match the name of any slave */
+	sscanf(buf, "%16s", ifname); /* IFNAMSIZ */
 
-		if (strlen(buf) == 0 || buf[0] == '\n') {
-			pr_info("%s: Setting primary slave to None.\n",
-				bond->dev->name);
-			bond->primary_slave = NULL;
-				bond_select_active_slave(bond);
-		} else {
-			pr_info("%s: Unable to set %.*s as primary slave as it is not a slave.\n",
-				bond->dev->name, (int)strlen(buf) - 1, buf);
+	/* check to see if we are clearing primary */
+	if (!strlen(ifname) || buf[0] == '\n') {
+		pr_info("%s: Setting primary slave to None.\n",
+			bond->dev->name);
+		bond->primary_slave = NULL;
+		bond_select_active_slave(bond);
+		goto out;
+	}
+
+	bond_for_each_slave(bond, slave, i) {
+		if (strncmp(slave->dev->name, ifname, IFNAMSIZ) == 0) {
+			pr_info("%s: Setting %s as primary slave.\n",
+				bond->dev->name, slave->dev->name);
+			bond->primary_slave = slave;
+			strcpy(bond->params.primary, slave->dev->name);
+			bond_select_active_slave(bond);
+			goto out;
 		}
 	}
+
+	pr_info("%s: Unable to set %.*s as primary slave.\n",
+		bond->dev->name, (int)strlen(buf) - 1, buf);
 out:
 	write_unlock_bh(&bond->curr_slave_lock);
 	read_unlock(&bond->lock);
@@ -1195,6 +1197,7 @@  static ssize_t bonding_store_active_slave(struct device *d,
 	struct slave *old_active = NULL;
 	struct slave *new_active = NULL;
 	struct bonding *bond = to_bond(d);
+	char ifname[IFNAMSIZ];
 
 	if (!rtnl_trylock())
 		return restart_syscall();
@@ -1203,56 +1206,59 @@  static ssize_t bonding_store_active_slave(struct device *d,
 	read_lock(&bond->lock);
 	write_lock_bh(&bond->curr_slave_lock);
 
-	if (!USES_PRIMARY(bond->params.mode))
+	if (!USES_PRIMARY(bond->params.mode)) {
 		pr_info("%s: Unable to change active slave; %s is in mode %d\n",
 			bond->dev->name, bond->dev->name, bond->params.mode);
-	else {
-		bond_for_each_slave(bond, slave, i) {
-			if (strnicmp
-			    (slave->dev->name, buf,
-			     strlen(slave->dev->name)) == 0) {
-        			old_active = bond->curr_active_slave;
-        			new_active = slave;
-        			if (new_active == old_active) {
-					/* do nothing */
-					pr_info("%s: %s is already the current active slave.\n",
+		goto out;
+	}
+
+	sscanf(buf, "%16s", ifname); /* IFNAMSIZ */
+
+	/* check to see if we are clearing primary */
+	if (!strlen(ifname) || buf[0] == '\n') {
+		pr_info("%s: Cannot clear primary slave.\n", bond->dev->name);
+		goto out;
+	}
+
+	bond_for_each_slave(bond, slave, i) {
+		if (strncmp(slave->dev->name, ifname, IFNAMSIZ) == 0) {
+			old_active = bond->curr_active_slave;
+			new_active = slave;
+			if (new_active == old_active) {
+				/* do nothing */
+				pr_info("%s: %s is already the current"
+					" active slave.\n",
+					bond->dev->name,
+					slave->dev->name);
+				goto out;
+			}
+			else {
+				if ((new_active) &&
+				    (old_active) &&
+				    (new_active->link == BOND_LINK_UP) &&
+				    IS_UP(new_active->dev)) {
+					pr_info("%s: Setting %s as active"
+						" slave.\n",
 						bond->dev->name,
 						slave->dev->name);
-					goto out;
+					bond_change_active_slave(bond,
+								 new_active);
 				}
 				else {
-        				if ((new_active) &&
-            				    (old_active) &&
-				            (new_active->link == BOND_LINK_UP) &&
-				            IS_UP(new_active->dev)) {
-						pr_info("%s: Setting %s as active slave.\n",
-							bond->dev->name,
-							slave->dev->name);
-							bond_change_active_slave(bond, new_active);
-        				}
-					else {
-						pr_info("%s: Could not set %s as active slave; either %s is down or the link is down.\n",
-							bond->dev->name,
-							slave->dev->name,
-							slave->dev->name);
-					}
-					goto out;
+					pr_info("%s: Could not set %s as"
+						" active slave; either %s is"
+						" down or the link is down.\n",
+						bond->dev->name,
+						slave->dev->name,
+						slave->dev->name);
 				}
+				goto out;
 			}
 		}
-
-		/* if we got here, then we didn't match the name of any slave */
-
-		if (strlen(buf) == 0 || buf[0] == '\n') {
-			pr_info("%s: Setting active slave to None.\n",
-				bond->dev->name);
-			bond->primary_slave = NULL;
-			bond_select_active_slave(bond);
-		} else {
-			pr_info("%s: Unable to set %.*s as active slave as it is not a slave.\n",
-				bond->dev->name, (int)strlen(buf) - 1, buf);
-		}
 	}
+
+	pr_info("%s: Unable to set %.*s as active slave.\n",
+		bond->dev->name, (int)strlen(buf) - 1, buf);
  out:
 	write_unlock_bh(&bond->curr_slave_lock);
 	read_unlock(&bond->lock);