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;
 }