diff mbox series

[v7,1/6] reiserfs: Switch to security_inode_init_security()

Message ID 20221201104125.919483-2-roberto.sassu@huaweicloud.com (mailing list archive)
State Handled Elsewhere
Headers show
Series evm: Do HMAC of multiple per LSM xattrs for new inodes | expand

Commit Message

Roberto Sassu Dec. 1, 2022, 10:41 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().

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>
---
 fs/reiserfs/xattr_security.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

Comments

Mimi Zohar Feb. 17, 2023, 7:47 p.m. UTC | #1
On Thu, 2022-12-01 at 11:41 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@huawei.com>
> 
> In preparation for removing security_old_inode_init_security(), switch to
> security_inode_init_security().
> 
> 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>

Now that commit 572302af1258 ("reiserfs: Add missing calls to
reiserfs_security_free()") is upstreamed, please include a dependency
comment.

Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>

> ---
>  fs/reiserfs/xattr_security.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/reiserfs/xattr_security.c b/fs/reiserfs/xattr_security.c
> index 857a65b05726..0ba96757681d 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;
diff mbox series

Patch

diff --git a/fs/reiserfs/xattr_security.c b/fs/reiserfs/xattr_security.c
index 857a65b05726..0ba96757681d 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;