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* [PATCH v2] security,fs,nfs,net: update security_inode_listsecurity() interface
@ 2025-04-28 19:50 Stephen Smalley
  2025-04-29  7:46 ` Christian Brauner
                   ` (3 more replies)
  0 siblings, 4 replies; 16+ messages in thread
From: Stephen Smalley @ 2025-04-28 19:50 UTC (permalink / raw)
  To: paul
  Cc: Stephen Smalley, Trond Myklebust, Anna Schumaker, Alexander Viro,
	Christian Brauner, Jan Kara, James Morris, Serge E. Hallyn,
	Eric Dumazet, Kuniyuki Iwashima, Paolo Abeni, Willem de Bruijn,
	David S. Miller, Jakub Kicinski, Simon Horman, Ondrej Mosnacek,
	Casey Schaufler, linux-nfs, linux-kernel, linux-fsdevel,
	linux-security-module, netdev, selinux

Update the security_inode_listsecurity() interface to allow
use of the xattr_list_one() helper and update the hook
implementations.

Link: https://lore.kernel.org/selinux/20250424152822.2719-1-stephen.smalley.work@gmail.com/

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
---
This patch is relative to the one linked above, which in theory is on
vfs.fixes but doesn't appear to have been pushed when I looked.

 fs/nfs/nfs4proc.c             | 10 ++++++----
 fs/xattr.c                    | 19 +++++++------------
 include/linux/lsm_hook_defs.h |  4 ++--
 include/linux/security.h      |  5 +++--
 net/socket.c                  | 17 +++++++----------
 security/security.c           | 16 ++++++++--------
 security/selinux/hooks.c      | 10 +++-------
 security/smack/smack_lsm.c    | 13 ++++---------
 8 files changed, 40 insertions(+), 54 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 970f28dbf253..6168a35cbd15 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -8023,12 +8023,14 @@ static int nfs4_xattr_get_nfs4_label(const struct xattr_handler *handler,
 static ssize_t
 nfs4_listxattr_nfs4_label(struct inode *inode, char *list, size_t list_len)
 {
-	int len = 0;
+	ssize_t len = 0;
 
 	if (nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL)) {
-		len = security_inode_listsecurity(inode, list, list_len);
-		if (len >= 0 && list_len && len > list_len)
-			return -ERANGE;
+		ssize_t remaining = list_len;
+
+		len = security_inode_listsecurity(inode, &list, &remaining);
+		if (!len)
+			len = list_len - remaining;
 	}
 	return len;
 }
diff --git a/fs/xattr.c b/fs/xattr.c
index 2fc314b27120..78387acab31b 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -492,9 +492,11 @@ vfs_listxattr(struct dentry *dentry, char *list, size_t size)
 	if (inode->i_op->listxattr) {
 		error = inode->i_op->listxattr(dentry, list, size);
 	} else {
-		error = security_inode_listsecurity(inode, list, size);
-		if (size && error > size)
-			error = -ERANGE;
+		ssize_t remaining = size;
+
+		error = security_inode_listsecurity(inode, &list, &remaining);
+		if (!error)
+			error = size - remaining;
 	}
 	return error;
 }
@@ -1469,17 +1471,10 @@ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
 	if (err)
 		return err;
 
-	err = security_inode_listsecurity(inode, buffer, remaining_size);
-	if (err < 0)
+	err = security_inode_listsecurity(inode, &buffer, &remaining_size);
+	if (err)
 		return err;
 
-	if (buffer) {
-		if (remaining_size < err)
-			return -ERANGE;
-		buffer += err;
-	}
-	remaining_size -= err;
-
 	read_lock(&xattrs->lock);
 	for (rbp = rb_first(&xattrs->rb_root); rbp; rbp = rb_next(rbp)) {
 		xattr = rb_entry(rbp, struct simple_xattr, rb_node);
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index bf3bbac4e02a..3c3919dcdebc 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -174,8 +174,8 @@ LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, struct mnt_idmap *idmap,
 	 struct inode *inode, const char *name, void **buffer, bool alloc)
 LSM_HOOK(int, -EOPNOTSUPP, inode_setsecurity, struct inode *inode,
 	 const char *name, const void *value, size_t size, int flags)
-LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char *buffer,
-	 size_t buffer_size)
+LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char **buffer,
+	 ssize_t *remaining_size)
 LSM_HOOK(void, LSM_RET_VOID, inode_getlsmprop, struct inode *inode,
 	 struct lsm_prop *prop)
 LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new)
diff --git a/include/linux/security.h b/include/linux/security.h
index cc9b54d95d22..0efc6a0ab56d 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -457,7 +457,7 @@ int security_inode_getsecurity(struct mnt_idmap *idmap,
 			       struct inode *inode, const char *name,
 			       void **buffer, bool alloc);
 int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
-int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
+int security_inode_listsecurity(struct inode *inode, char **buffer, ssize_t *remaining_size);
 void security_inode_getlsmprop(struct inode *inode, struct lsm_prop *prop);
 int security_inode_copy_up(struct dentry *src, struct cred **new);
 int security_inode_copy_up_xattr(struct dentry *src, const char *name);
@@ -1077,7 +1077,8 @@ static inline int security_inode_setsecurity(struct inode *inode, const char *na
 	return -EOPNOTSUPP;
 }
 
-static inline int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
+static inline int security_inode_listsecurity(struct inode *inode,
+					char **buffer, ssize_t *remaining_size)
 {
 	return 0;
 }
diff --git a/net/socket.c b/net/socket.c
index 9a0e720f0859..bbcaa3371fcd 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -560,17 +560,14 @@ static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
 				size_t size)
 {
 	ssize_t len;
-	ssize_t used = 0;
+	ssize_t used, remaining;
+	int err;
 
-	len = security_inode_listsecurity(d_inode(dentry), buffer, size);
-	if (len < 0)
-		return len;
-	used += len;
-	if (buffer) {
-		if (size < used)
-			return -ERANGE;
-		buffer += len;
-	}
+	err = security_inode_listsecurity(d_inode(dentry), &buffer,
+					  &remaining);
+	if (err)
+		return err;
+	used = size - remaining;
 
 	len = (XATTR_NAME_SOCKPROTONAME_LEN + 1);
 	used += len;
diff --git a/security/security.c b/security/security.c
index fb57e8fddd91..3985d040d5a9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2710,22 +2710,22 @@ int security_inode_setsecurity(struct inode *inode, const char *name,
 /**
  * security_inode_listsecurity() - List the xattr security label names
  * @inode: inode
- * @buffer: buffer
- * @buffer_size: size of buffer
+ * @buffer: pointer to buffer
+ * @remaining_size: pointer to remaining size of buffer
  *
  * Copy the extended attribute names for the security labels associated with
- * @inode into @buffer.  The maximum size of @buffer is specified by
- * @buffer_size.  @buffer may be NULL to request the size of the buffer
- * required.
+ * @inode into *(@buffer).  The remaining size of @buffer is specified by
+ * *(@remaining_size).  *(@buffer) may be NULL to request the size of the
+ * buffer required. Updates *(@buffer) and *(@remaining_size).
  *
- * Return: Returns number of bytes used/required on success.
+ * Return: Returns 0 on success, or -errno on failure.
  */
 int security_inode_listsecurity(struct inode *inode,
-				char *buffer, size_t buffer_size)
+				char **buffer, ssize_t *remaining_size)
 {
 	if (unlikely(IS_PRIVATE(inode)))
 		return 0;
-	return call_int_hook(inode_listsecurity, inode, buffer, buffer_size);
+	return call_int_hook(inode_listsecurity, inode, buffer, remaining_size);
 }
 EXPORT_SYMBOL(security_inode_listsecurity);
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b8115df536ab..e6c98ebbf7bc 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3612,16 +3612,12 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
 	return 0;
 }
 
-static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
+static int selinux_inode_listsecurity(struct inode *inode, char **buffer,
+				ssize_t *remaining_size)
 {
-	const int len = sizeof(XATTR_NAME_SELINUX);
-
 	if (!selinux_initialized())
 		return 0;
-
-	if (buffer && len <= buffer_size)
-		memcpy(buffer, XATTR_NAME_SELINUX, len);
-	return len;
+	return xattr_list_one(buffer, remaining_size, XATTR_NAME_SELINUX);
 }
 
 static void selinux_inode_getlsmprop(struct inode *inode, struct lsm_prop *prop)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 99833168604e..3f7ac865532e 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1619,17 +1619,12 @@ static int smack_inode_getsecurity(struct mnt_idmap *idmap,
  * smack_inode_listsecurity - list the Smack attributes
  * @inode: the object
  * @buffer: where they go
- * @buffer_size: size of buffer
+ * @remaining_size: size of buffer
  */
-static int smack_inode_listsecurity(struct inode *inode, char *buffer,
-				    size_t buffer_size)
+static int smack_inode_listsecurity(struct inode *inode, char **buffer,
+				    ssize_t *remaining_size)
 {
-	int len = sizeof(XATTR_NAME_SMACK);
-
-	if (buffer != NULL && len <= buffer_size)
-		memcpy(buffer, XATTR_NAME_SMACK, len);
-
-	return len;
+	return xattr_list_one(buffer, remaining_size, XATTR_NAME_SMACK);
 }
 
 /**
-- 
2.49.0


^ permalink raw reply related	[flat|nested] 16+ messages in thread
end of thread, other threads:[~2025-07-24  2:10 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-04-28 19:50 [PATCH v2] security,fs,nfs,net: update security_inode_listsecurity() interface Stephen Smalley
2025-04-29  7:46 ` Christian Brauner
2025-04-29 12:25   ` Stephen Smalley
2025-04-29 23:34 ` Paul Moore
2025-05-20 21:31   ` Paul Moore
2025-05-21  0:22     ` Casey Schaufler
2025-05-27 21:03     ` Anna Schumaker
2025-06-19 21:18       ` Paul Moore
2025-07-24  2:09         ` Paul Moore
2025-06-05 18:09   ` Stephen Smalley
2025-06-05 18:24     ` Paul Moore
2025-05-21  0:31 ` Kuniyuki Iwashima
2025-06-19 21:04   ` Paul Moore
2025-06-06 13:39 ` Konstantin Andreev
2025-06-06 14:28   ` Stephen Smalley
2025-06-06 15:24     ` Konstantin Andreev

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