diff mbox series

[v8,1/6] reiserfs: Switch to security_inode_init_security()

Message ID 20230314081720.4158676-2-roberto.sassu@huaweicloud.com
State New
Headers
Series evm: Do HMAC of multiple per LSM xattrs for new inodes |

Commit Message

Roberto Sassu March 14, 2023, 8:17 a.m. UTC 
  From: Roberto Sassu <roberto.sassu@huawei.com>

In preparation for removing security_old_inode_init_security(), switch to
security_inode_init_security(). Commit 572302af1258 ("reiserfs: Add missing
calls to reiserfs_security_free()") fixed possible memory leaks and another
issue related to adding an xattr at inode creation time.

Define the initxattrs callback reiserfs_initxattrs(), to populate the
name/value/len triple in the reiserfs_security_handle() with the first
xattr provided by LSMs. Make a copy of the xattr value, as
security_inode_init_security() frees it.

After the call to security_inode_init_security(), remove the check for
returning -EOPNOTSUPP, as security_inode_init_security() changes it to
zero.

Multiple xattrs are currently not supported, as the
reiserfs_security_handle structure is exported to user space. As a
consequence, even if EVM is invoked, it will not provide an xattr (if it
is not the first to set it, its xattr will be discarded; if it is the
first, it does not have xattrs to calculate the HMAC on).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
 fs/reiserfs/xattr_security.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

Comments

Paul Moore March 23, 2023, 11:33 p.m. UTC | #1 
On Tue, Mar 14, 2023 at 4:18 AM Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
>
> From: Roberto Sassu <roberto.sassu@huawei.com>
>
> In preparation for removing security_old_inode_init_security(), switch to
> security_inode_init_security(). Commit 572302af1258 ("reiserfs: Add missing
> calls to reiserfs_security_free()") fixed possible memory leaks and another
> issue related to adding an xattr at inode creation time.
>
> Define the initxattrs callback reiserfs_initxattrs(), to populate the
> name/value/len triple in the reiserfs_security_handle() with the first
> xattr provided by LSMs. Make a copy of the xattr value, as
> security_inode_init_security() frees it.
>
> After the call to security_inode_init_security(), remove the check for
> returning -EOPNOTSUPP, as security_inode_init_security() changes it to
> zero.
>
> Multiple xattrs are currently not supported, as the
> reiserfs_security_handle structure is exported to user space. As a
> consequence, even if EVM is invoked, it will not provide an xattr (if it
> is not the first to set it, its xattr will be discarded; if it is the
> first, it does not have xattrs to calculate the HMAC on).
>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> ---
>  fs/reiserfs/xattr_security.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)

Merged into lsm/next, thanks.
diff mbox series

Patch

diff --git a/fs/reiserfs/xattr_security.c b/fs/reiserfs/xattr_security.c
index 41c0ea84fbf..6bffdf9a4fd 100644
--- a/fs/reiserfs/xattr_security.c
+++ b/fs/reiserfs/xattr_security.c
@@ -39,6 +39,22 @@  static bool security_list(struct dentry *dentry)
 	return !IS_PRIVATE(d_inode(dentry));
 }
 
+static int
+reiserfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		    void *fs_info)
+{
+	struct reiserfs_security_handle *sec = fs_info;
+
+	sec->value = kmemdup(xattr_array->value, xattr_array->value_len,
+			     GFP_KERNEL);
+	if (!sec->value)
+		return -ENOMEM;
+
+	sec->name = xattr_array->name;
+	sec->length = xattr_array->value_len;
+	return 0;
+}
+
 /* Initializes the security context for a new inode and returns the number
  * of blocks needed for the transaction. If successful, reiserfs_security
  * must be released using reiserfs_security_free when the caller is done. */
@@ -56,12 +72,9 @@  int reiserfs_security_init(struct inode *dir, struct inode *inode,
 	if (IS_PRIVATE(dir))
 		return 0;
 
-	error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
-						 &sec->value, &sec->length);
+	error = security_inode_init_security(inode, dir, qstr,
+					     &reiserfs_initxattrs, sec);
 	if (error) {
-		if (error == -EOPNOTSUPP)
-			error = 0;
-
 		sec->name = NULL;
 		sec->value = NULL;
 		sec->length = 0;