vfs: move cap_convert_nscap() call into vfs_setxattr()

cap_convert_nscap() does permission checking as well as conversion of the
xattr value conditionally based on fs's user-ns.

This is needed by overlayfs and probably other layered fs (ecryptfs) and is
what vfs_foo() is supposed to do anyway.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: James Morris <jamorris@linux.microsoft.com>

diff --git a/fs/xattr.c b/fs/xattr.c
index cd7a563e8bcd471d2b08bdb1cfad85ced1983660..fd57153b1f6170f2780736c4d0221afd40be21fa 100644 (file)
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -276,8 +276,16 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 {
        struct inode *inode = dentry->d_inode;
        struct inode *delegated_inode = NULL;
+       const void  *orig_value = value;
        int error;
 
+       if (size && strcmp(name, XATTR_NAME_CAPS) == 0) {
+               error = cap_convert_nscap(dentry, &value, size);
+               if (error < 0)
+                       return error;
+               size = error;
+       }
+
 retry_deleg:
        inode_lock(inode);
        error = __vfs_setxattr_locked(dentry, name, value, size, flags,
@@ -289,6 +297,9 @@ retry_deleg:
                if (!error)
                        goto retry_deleg;
        }
+       if (value != orig_value)
+               kfree(value);
+
        return error;
 }
 EXPORT_SYMBOL_GPL(vfs_setxattr);
@@ -537,12 +548,6 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
                if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
                    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
                        posix_acl_fix_xattr_from_user(kvalue, size);
-               else if (strcmp(kname, XATTR_NAME_CAPS) == 0) {
-                       error = cap_convert_nscap(d, &kvalue, size);
-                       if (error < 0)
-                               goto out;
-                       size = error;
-               }
        }
 
        error = vfs_setxattr(d, kname, kvalue, size, flags);

diff --git a/include/linux/capability.h b/include/linux/capability.h
index 1e7fe311cabe3ba7cbbac5c3dff9934639ae8808..b2f698915c0f3f41fbc13c49d0eeedc1c95c0af8 100644 (file)
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -270,6 +270,6 @@ static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns)
 /* audit system wants to get cap info from files as well */
 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
 
-extern int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size);
+extern int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size);
 
 #endif /* !_LINUX_CAPABILITY_H */

diff --git a/security/commoncap.c b/security/commoncap.c
index 59bf3c1674c8b4dbb960b5ac851b3d3afc78c1f9..bacc1111d871bc257c5f86bbf206430f64cb8d79 100644 (file)
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -473,7 +473,7 @@ static bool validheader(size_t size, const struct vfs_cap_data *cap)
  *
  * If all is ok, we return the new size, on error return < 0.
  */
-int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size)
+int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size)
 {
        struct vfs_ns_cap_data *nscap;
        uid_t nsrootid;
@@ -516,7 +516,6 @@ int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size)
        nscap->magic_etc = cpu_to_le32(nsmagic);
        memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32);
 
-       kvfree(*ivalue);
        *ivalue = nscap;
        return newsize;
 }