[PATCH] SELinux: canonicalize getxattr()

[linux.git] / fs / xattr.c

diff --git a/fs/xattr.c b/fs/xattr.c
index 6acd5c63da9113613132492dea834d8304554fd8..f6e00c0e114f6225d1f7af66517dd537aa0724bf 100644 (file)
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -51,20 +51,29 @@ setxattr(struct dentry *d, char __user *name, void __user *value,
                }
        }
 
+       down(&d->d_inode->i_sem);
+       error = security_inode_setxattr(d, kname, kvalue, size, flags);
+       if (error)
+               goto out;
        error = -EOPNOTSUPP;
        if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
-               down(&d->d_inode->i_sem);
-               error = security_inode_setxattr(d, kname, kvalue, size, flags);
-               if (error)
-                       goto out;
-               error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
+               error = d->d_inode->i_op->setxattr(d, kname, kvalue,
+                                                  size, flags);
                if (!error) {
                        fsnotify_xattr(d);
-                       security_inode_post_setxattr(d, kname, kvalue, size, flags);
+                       security_inode_post_setxattr(d, kname, kvalue,
+                                                    size, flags);
                }
-out:
-               up(&d->d_inode->i_sem);
+       } else if (!strncmp(kname, XATTR_SECURITY_PREFIX,
+                           sizeof XATTR_SECURITY_PREFIX - 1)) {
+               const char *suffix = kname + sizeof XATTR_SECURITY_PREFIX - 1;
+               error = security_inode_setsecurity(d->d_inode, suffix, kvalue,
+                                                  size, flags);
+               if (!error)
+                       fsnotify_xattr(d);
        }
+out:
+       up(&d->d_inode->i_sem);
        if (kvalue)
                kfree(kvalue);
        return error;
@@ -134,25 +143,34 @@ getxattr(struct dentry *d, char __user *name, void __user *value, size_t size)
        if (size) {
                if (size > XATTR_SIZE_MAX)
                        size = XATTR_SIZE_MAX;
-               kvalue = kmalloc(size, GFP_KERNEL);
+               kvalue = kzalloc(size, GFP_KERNEL);
                if (!kvalue)
                        return -ENOMEM;
        }
 
+       error = security_inode_getxattr(d, kname);
+       if (error)
+               goto out;
        error = -EOPNOTSUPP;
-       if (d->d_inode->i_op && d->d_inode->i_op->getxattr) {
-               error = security_inode_getxattr(d, kname);
-               if (error)
-                       goto out;
+       if (d->d_inode->i_op && d->d_inode->i_op->getxattr)
                error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
-               if (error > 0) {
-                       if (size && copy_to_user(value, kvalue, error))
-                               error = -EFAULT;
-               } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
-                       /* The file system tried to returned a value bigger
-                          than XATTR_SIZE_MAX bytes. Not possible. */
-                       error = -E2BIG;
-               }
+
+       if (!strncmp(kname, XATTR_SECURITY_PREFIX,
+                    sizeof XATTR_SECURITY_PREFIX - 1)) {
+               const char *suffix = kname + sizeof XATTR_SECURITY_PREFIX - 1;
+               int rv = security_inode_getsecurity(d->d_inode, suffix, kvalue,
+                                                   size, error);
+               /* Security module active: overwrite error value */
+               if (rv != -EOPNOTSUPP)
+                       error = rv;
+       }
+       if (error > 0) {
+               if (size && copy_to_user(value, kvalue, error))
+                       error = -EFAULT;
+       } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
+               /* The file system tried to returned a value bigger
+                  than XATTR_SIZE_MAX bytes. Not possible. */
+               error = -E2BIG;
        }
 out:
        if (kvalue)
@@ -221,20 +239,24 @@ listxattr(struct dentry *d, char __user *list, size_t size)
                        return -ENOMEM;
        }
 
+       error = security_inode_listxattr(d);
+       if (error)
+               goto out;
        error = -EOPNOTSUPP;
        if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
-               error = security_inode_listxattr(d);
-               if (error)
-                       goto out;
                error = d->d_inode->i_op->listxattr(d, klist, size);
-               if (error > 0) {
-                       if (size && copy_to_user(list, klist, error))
-                               error = -EFAULT;
-               } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
-                       /* The file system tried to returned a list bigger
-                          than XATTR_LIST_MAX bytes. Not possible. */
-                       error = -E2BIG;
-               }
+       } else {
+               error = security_inode_listsecurity(d->d_inode, klist, size);
+               if (size && error >= size)
+                       error = -ERANGE;
+       }
+       if (error > 0) {
+               if (size && copy_to_user(list, klist, error))
+                       error = -EFAULT;
+       } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
+               /* The file system tried to returned a list bigger
+                  than XATTR_LIST_MAX bytes. Not possible. */
+               error = -E2BIG;
        }
 out:
        if (klist)
@@ -307,6 +329,8 @@ removexattr(struct dentry *d, char __user *name)
                down(&d->d_inode->i_sem);
                error = d->d_inode->i_op->removexattr(d, kname);
                up(&d->d_inode->i_sem);
+               if (!error)
+                       fsnotify_xattr(d);
        }
 out:
        return error;