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>

1 files changed, 14 insertions, 9 deletions

diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 949706c336..626bdd3c3d 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -29,6 +29,8 @@
 
 #define KOBJ_NAME_LEN                   20
 #define UEVENT_HELPER_PATH_LEN          256
+#define UEVENT_NUM_ENVP                 32      /* number of env pointers */
+#define UEVENT_BUFFER_SIZE              2048    /* buffer for the variables */
 
 /* path to the userspace helper executed on an event */
 extern char uevent_helper[];
@@ -111,11 +113,18 @@ struct kobj_type {
         struct attribute        ** default_attrs;
 };
 
+struct kobj_uevent_env {
+        char *envp[UEVENT_NUM_ENVP];
+        int envp_idx;
+        char buf[UEVENT_BUFFER_SIZE];
+        int buflen;
+};
+
 struct kset_uevent_ops {
         int (*filter)(struct kset *kset, struct kobject *kobj);
         const char *(*name)(struct kset *kset, struct kobject *kobj);
-        int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
-                        int num_envp, char *buffer, int buffer_size);
+        int (*uevent)(struct kset *kset, struct kobject *kobj,
+                      struct kobj_uevent_env *env);
 };
 
 /*
@@ -275,10 +284,8 @@ int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
                         char *envp[]);
 
-int add_uevent_var(char **envp, int num_envp, int *cur_index,
-                        char *buffer, int buffer_size, int *cur_len,
-                        const char *format, ...)
-        __attribute__((format (printf, 7, 8)));
+int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
+        __attribute__((format (printf, 2, 3)));
 #else
 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 { return 0; }
@@ -287,9 +294,7 @@ static inline int kobject_uevent_env(struct kobject *kobj,
                                       char *envp[])
 { return 0; }
 
-static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
-                                      char *buffer, int buffer_size, int *cur_len, 
-                                      const char *format, ...)
+static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 { return 0; }
 #endif