[AppArmor 32/44] Enable LSM hooks to distinguish operations on file descriptors from operations on pathnames

[jjohansen]

Struct iattr already contains ia_file since commit cc4e69de from 
Miklos (which is related to commit befc649c). Use this to pass
struct file down the setattr hooks. This allows LSMs to distinguish
operations on file descriptors from operations on paths.

Signed-off-by: Andreas Gruenbacher <agruen@xxxxxxx>
Signed-off-by: John Johansen <jjohansen@xxxxxxx>
Cc: Miklos Szeredi <mszeredi@xxxxxxx>

---
 fs/nfsd/vfs.c      |   12 +++++++-----
 fs/open.c          |   16 +++++++++++-----
 include/linux/fs.h |    3 +++
 3 files changed, 21 insertions(+), 10 deletions(-)

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -383,7 +383,7 @@ static ssize_t nfsd_getxattr(struct dent
 {
 	ssize_t buflen;
 
-	buflen = vfs_getxattr(dentry, mnt, key, NULL, 0);
+	buflen = vfs_getxattr(dentry, mnt, key, NULL, 0, NULL);
 	if (buflen <= 0)
 		return buflen;
 
@@ -391,7 +391,7 @@ static ssize_t nfsd_getxattr(struct dent
 	if (!*buf)
 		return -ENOMEM;
 
-	return vfs_getxattr(dentry, mnt, key, *buf, buflen);
+	return vfs_getxattr(dentry, mnt, key, *buf, buflen, NULL);
 }
 #endif
 
@@ -417,7 +417,7 @@ set_nfsv4_acl_one(struct dentry *dentry,
 		goto out;
 	}
 
-	error = vfs_setxattr(dentry, mnt, key, buf, len, 0);
+	error = vfs_setxattr(dentry, mnt, key, buf, len, 0, NULL);
 out:
 	kfree(buf);
 	return error;
@@ -1992,12 +1992,14 @@ nfsd_set_posix_acl(struct svc_fh *fhp, i
 
 	mnt = fhp->fh_export->ex_mnt;
 	if (size)
-		error = vfs_setxattr(fhp->fh_dentry, mnt, name, value, size,0);
+		error = vfs_setxattr(fhp->fh_dentry, mnt, name, value, size, 0,
+				     NULL);
 	else {
 		if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
 			error = 0;
 		else {
-			error = vfs_removexattr(fhp->fh_dentry, mnt, name);
+			error = vfs_removexattr(fhp->fh_dentry, mnt, name,
+						NULL);
 			if (error == -ENODATA)
 				error = 0;
 		}
--- a/fs/open.c
+++ b/fs/open.c
@@ -522,6 +522,8 @@ asmlinkage long sys_fchmod(unsigned int 
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
+	newattrs.ia_valid |= ATTR_FILE;
+	newattrs.ia_file = file;
 	err = notify_change(dentry, file->f_path.mnt, &newattrs);
 	mutex_unlock(&inode->i_mutex);
 
@@ -572,7 +574,7 @@ asmlinkage long sys_chmod(const char __u
 }
 
 static int chown_common(struct dentry * dentry, struct vfsmount *mnt,
-			uid_t user, gid_t group)
+			uid_t user, gid_t group, struct file *file)
 {
 	struct inode * inode;
 	int error;
@@ -600,6 +602,10 @@ static int chown_common(struct dentry * 
 	}
 	if (!S_ISDIR(inode->i_mode))
 		newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID;
+	if (file) {
+		newattrs.ia_file = file;
+		newattrs.ia_valid |= ATTR_FILE;
+	}
 	mutex_lock(&inode->i_mutex);
 	error = notify_change(dentry, mnt, &newattrs);
 	mutex_unlock(&inode->i_mutex);
@@ -615,7 +621,7 @@ asmlinkage long sys_chown(const char __u
 	error = user_path_walk(filename, &nd);
 	if (error)
 		goto out;
-	error = chown_common(nd.dentry, nd.mnt, user, group);
+	error = chown_common(nd.dentry, nd.mnt, user, group, NULL);
 	path_release(&nd);
 out:
 	return error;
@@ -635,7 +641,7 @@ asmlinkage long sys_fchownat(int dfd, co
 	error = __user_walk_fd(dfd, filename, follow, &nd);
 	if (error)
 		goto out;
-	error = chown_common(nd.dentry, nd.mnt, user, group);
+	error = chown_common(nd.dentry, nd.mnt, user, group, NULL);
 	path_release(&nd);
 out:
 	return error;
@@ -649,7 +655,7 @@ asmlinkage long sys_lchown(const char __
 	error = user_path_walk_link(filename, &nd);
 	if (error)
 		goto out;
-	error = chown_common(nd.dentry, nd.mnt, user, group);
+	error = chown_common(nd.dentry, nd.mnt, user, group, NULL);
 	path_release(&nd);
 out:
 	return error;
@@ -668,7 +674,7 @@ asmlinkage long sys_fchown(unsigned int 
 
 	dentry = file->f_path.dentry;
 	audit_inode(NULL, dentry->d_inode);
-	error = chown_common(dentry, file->f_path.mnt, user, group);
+	error = chown_common(dentry, file->f_path.mnt, user, group, file);
 	fput(file);
 out:
 	return error;
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -351,6 +351,9 @@ struct iattr {
 	 * Not an attribute, but an auxilary info for filesystems wanting to
 	 * implement an ftruncate() like method.  NOTE: filesystem should
 	 * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
+	 *
+	 * The LSM hooks also use this to distinguish operations on a file
+	 * descriptors from operations on pathnames.
 	 */
 	struct file	*ia_file;
 };

-- 
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