[PATCH] sanitize security_getprocattr() API

have it return the buffer it had allocated

Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 17 insertions, 22 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 01f7769da8e6..989af5e55d1b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1558,29 +1558,20 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
                                   size_t count, loff_t *ppos)
 {
         struct inode * inode = file->f_path.dentry->d_inode;
-        unsigned long page;
+        char *p = NULL;
         ssize_t length;
         struct task_struct *task = get_proc_task(inode);
 
-        length = -ESRCH;
         if (!task)
-                goto out_no_task;
-
-        if (count > PAGE_SIZE)
-                count = PAGE_SIZE;
-        length = -ENOMEM;
-        if (!(page = __get_free_page(GFP_KERNEL)))
-                goto out;
+                return -ESRCH;
 
         length = security_getprocattr(task,
                                       (char*)file->f_path.dentry->d_name.name,
-                                      (void*)page, count);
-        if (length >= 0)
-                length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
-        free_page(page);
-out:
+                                      &p);
         put_task_struct(task);
-out_no_task:
+        if (length > 0)
+                length = simple_read_from_buffer(buf, count, ppos, p, length);
+        kfree(p);
         return length;
 }
 
diff --git a/include/linux/security.h b/include/linux/security.h
index 7f88d97575fd..47e82c120f9a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1324,7 +1324,7 @@ struct security_operations {
 
         void (*d_instantiate) (struct dentry *dentry, struct inode *inode);
 
-        int (*getprocattr)(struct task_struct *p, char *name, void *value, size_t size);
+        int (*getprocattr)(struct task_struct *p, char *name, char **value);
         int (*setprocattr)(struct task_struct *p, char *name, void *value, size_t size);
         int (*secid_to_secctx)(u32 secid, char **secdata, u32 *seclen);
         void (*release_secctx)(char *secdata, u32 seclen);
@@ -2092,9 +2092,9 @@ static inline void security_d_instantiate (struct dentry *dentry, struct inode *
         security_ops->d_instantiate (dentry, inode);
 }
 
-static inline int security_getprocattr(struct task_struct *p, char *name, void *value, size_t size)
+static inline int security_getprocattr(struct task_struct *p, char *name, char **value)
 {
-        return security_ops->getprocattr(p, name, value, size);
+        return security_ops->getprocattr(p, name, value);
 }
 
 static inline int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
@@ -2749,7 +2749,7 @@ static inline int security_sem_semop (struct sem_array * sma,
 static inline void security_d_instantiate (struct dentry *dentry, struct inode *inode)
 { }
 
-static inline int security_getprocattr(struct task_struct *p, char *name, void *value, size_t size)
+static inline int security_getprocattr(struct task_struct *p, char *name, char **value)
 {
         return -EINVAL;
 }
diff --git a/security/dummy.c b/security/dummy.c
index 558795b237d6..8ffd76405b5b 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -907,7 +907,7 @@ static void dummy_d_instantiate (struct dentry *dentry, struct inode *inode)
         return;
 }
 
-static int dummy_getprocattr(struct task_struct *p, char *name, void *value, size_t size)
+static int dummy_getprocattr(struct task_struct *p, char *name, char **value)
 {
         return -EINVAL;
 }
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 19a385e9968e..d41e24d6ae41 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4468,11 +4468,12 @@ static void selinux_d_instantiate (struct dentry *dentry, struct inode *inode)
 }
 
 static int selinux_getprocattr(struct task_struct *p,
-                               char *name, void *value, size_t size)
+                               char *name, char **value)
 {
         struct task_security_struct *tsec;
         u32 sid;
         int error;
+        unsigned len;
 
         if (current != p) {
                 error = task_has_perm(current, p, PROCESS__GETATTR);
@@ -4500,7 +4501,10 @@ static int selinux_getprocattr(struct task_struct *p,
         if (!sid)
                 return 0;
 
-        return selinux_getsecurity(sid, value, size);
+        error = security_sid_to_context(sid, value, &len);
+        if (error)
+                return error;
+        return len;
 }
 
 static int selinux_setprocattr(struct task_struct *p,