Driver core: change add_uevent_var to use a struct

This changes the uevent buffer functions to use a struct instead of a
long list of parameters. It does no longer require the caller to do the
proper buffer termination and size accounting, which is currently wrong
in some places. It fixes a known bug where parts of the uevent
environment are overwritten because of wrong index calculations.

Many thanks to Mathieu Desnoyers for finding bugs and improving the
error handling.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 16 insertions, 46 deletions

diff --git a/arch/powerpc/kernel/of_device.c b/arch/powerpc/kernel/of_device.c
index 89b911e83c04..8f3db32fac8b 100644
--- a/arch/powerpc/kernel/of_device.c
+++ b/arch/powerpc/kernel/of_device.c
@@ -57,26 +57,21 @@ ssize_t of_device_get_modalias(struct of_device *ofdev,
 	return tsize;
 }
 
-int of_device_uevent(struct device *dev,
-		char **envp, int num_envp, char *buffer, int buffer_size)
+int of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct of_device *ofdev;
 	const char *compat;
-	int i = 0, length = 0, seen = 0, cplen, sl;
+	int seen = 0, cplen, sl;
 
 	if (!dev)
 		return -ENODEV;
 
 	ofdev = to_of_device(dev);
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "OF_NAME=%s", ofdev->node->name))
+	if (add_uevent_var(env, "OF_NAME=%s", ofdev->node->name))
 		return -ENOMEM;
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "OF_TYPE=%s", ofdev->node->type))
+	if (add_uevent_var(env, "OF_TYPE=%s", ofdev->node->type))
 		return -ENOMEM;
 
         /* Since the compatible field can contain pretty much anything
@@ -85,9 +80,7 @@ int of_device_uevent(struct device *dev,
 
 	compat = of_get_property(ofdev->node, "compatible", &cplen);
 	while (compat && *compat && cplen > 0) {
-		if (add_uevent_var(envp, num_envp, &i,
-				   buffer, buffer_size, &length,
-				   "OF_COMPATIBLE_%d=%s", seen, compat))
+		if (add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat))
 			return -ENOMEM;
 
 		sl = strlen (compat) + 1;
@@ -96,25 +89,17 @@ int of_device_uevent(struct device *dev,
 		seen++;
 	}
 
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "OF_COMPATIBLE_N=%d", seen))
+	if (add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen))
 		return -ENOMEM;
 
 	/* modalias is trickier, we add it in 2 steps */
-	if (add_uevent_var(envp, num_envp, &i,
-			   buffer, buffer_size, &length,
-			   "MODALIAS="))
+	if (add_uevent_var(env, "MODALIAS="))
 		return -ENOMEM;
-
-	sl = of_device_get_modalias(ofdev, &buffer[length-1],
-					buffer_size-length);
-	if (sl >= (buffer_size-length))
+	sl = of_device_get_modalias(ofdev, &env->buf[env->buflen-1],
+				    sizeof(env->buf) - env->buflen);
+	if (sl >= (sizeof(env->buf) - env->buflen))
 		return -ENOMEM;
-
-	length += sl;
-
-	envp[i] = NULL;
+	env->buflen += sl;
 
 	return 0;
 }
diff --git a/arch/powerpc/kernel/vio.c b/arch/powerpc/kernel/vio.c
index cb22a3557c4e..19a5656001c0 100644
--- a/arch/powerpc/kernel/vio.c
+++ b/arch/powerpc/kernel/vio.c
@@ -317,30 +317,20 @@ static int vio_bus_match(struct device *dev, struct device_driver *drv)
 	return (ids != NULL) && (vio_match_device(ids, vio_dev) != NULL);
 }
 
-static int vio_hotplug(struct device *dev, char **envp, int num_envp,
-			char *buffer, int buffer_size)
+static int vio_hotplug(struct device *dev, struct kobj_uevent_env *env)
 {
 	const struct vio_dev *vio_dev = to_vio_dev(dev);
 	struct device_node *dn;
 	const char *cp;
-	int length;
-
-	if (!num_envp)
-		return -ENOMEM;
 
 	dn = dev->archdata.of_node;
 	if (!dn)
 		return -ENODEV;
-	cp = of_get_property(dn, "compatible", &length);
+	cp = of_get_property(dn, "compatible", NULL);
 	if (!cp)
 		return -ENODEV;
 
-	envp[0] = buffer;
-	length = scnprintf(buffer, buffer_size, "MODALIAS=vio:T%sS%s",
-				vio_dev->type, cp);
-	if ((buffer_size - length) <= 0)
-		return -ENOMEM;
-	envp[1] = NULL;
+	add_uevent_var(env, "MODALIAS=vio:T%sS%s", vio_dev->type, cp);
 	return 0;
 }
 
diff --git a/arch/powerpc/platforms/ps3/system-bus.c b/arch/powerpc/platforms/ps3/system-bus.c
index 4bb634a17e43..ea0b2c790412 100644
--- a/arch/powerpc/platforms/ps3/system-bus.c
+++ b/arch/powerpc/platforms/ps3/system-bus.c
@@ -437,18 +437,13 @@ static void ps3_system_bus_shutdown(struct device *_dev)
 	dev_dbg(&dev->core, " <- %s:%d\n", __func__, __LINE__);
 }
 
-static int ps3_system_bus_uevent(struct device *_dev, char **envp,
-				 int num_envp, char *buffer, int buffer_size)
+static int ps3_system_bus_uevent(struct device *_dev, struct kobj_uevent_env *env)
 {
 	struct ps3_system_bus_device *dev = ps3_dev_to_system_bus_dev(_dev);
 	int i = 0, length = 0;
 
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-			   &length, "MODALIAS=ps3:%d",
-			   dev->match_id))
+	if (add_uevent_var(env, "MODALIAS=ps3:%d", dev->match_id))
 		return -ENOMEM;
-
-	envp[i] = NULL;
 	return 0;
 }