[PATCH v2] security: Return xattr name from security_dentry_init_security()

[PATCH v2] security: Return xattr name from security_dentry_init_security()

[Vivek Goyal]

Right now security_dentry_init_security() only supports single security
label and is used by SELinux only. There are two users of of this hook,
namely ceph and nfs.

NFS does not care about xattr name. Ceph hardcodes the xattr name to
security.selinux (XATTR_NAME_SELINUX).

I am making changes to fuse/virtiofs to send security label to virtiofsd
and I need to send xattr name as well. I also hardcoded the name of
xattr to security.selinux.

Stephen Smalley suggested that it probably is a good idea to modify
security_dentry_init_security() to also return name of xattr so that
we can avoid this hardcoding in the callers.

This patch adds a new parameter "const char **xattr_name" to
security_dentry_init_security() and LSM puts the name of xattr
too if caller asked for it (xattr_name != NULL).

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
---

Changes since v1:
- Updated comment to make it clear caller does not have to free the
  xattr_name. (Jeff Layton).
- Captured Jeff's Reviewed-by ack.

I have tested this patch with virtiofs and compile tested for ceph and nfs.

NFS changes are trivial. Looking for an ack from NFS maintainers.

---
 fs/ceph/xattr.c               |    3 +--
 fs/nfs/nfs4proc.c             |    3 ++-
 include/linux/lsm_hook_defs.h |    3 ++-
 include/linux/lsm_hooks.h     |    3 +++
 include/linux/security.h      |    6 ++++--
 security/security.c           |    7 ++++---
 security/selinux/hooks.c      |    6 +++++-
 7 files changed, 21 insertions(+), 10 deletions(-)

Index: redhat-linux/security/selinux/hooks.c
===================================================================
--- redhat-linux.orig/security/selinux/hooks.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/security/selinux/hooks.c	2021-10-06 15:20:57.745247170 -0400
@@ -2948,7 +2948,8 @@ static void selinux_inode_free_security(
 }
 
 static int selinux_dentry_init_security(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
+					const struct qstr *name,
+					const char **xattr_name, void **ctx,
 					u32 *ctxlen)
 {
 	u32 newsid;
@@ -2961,6 +2962,9 @@ static int selinux_dentry_init_security(
 	if (rc)
 		return rc;
 
+	if (xattr_name)
+		*xattr_name = XATTR_NAME_SELINUX;
+
 	return security_sid_to_context(&selinux_state, newsid, (char **)ctx,
 				       ctxlen);
 }
Index: redhat-linux/security/security.c
===================================================================
--- redhat-linux.orig/security/security.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/security/security.c	2021-10-06 15:20:57.749247170 -0400
@@ -1052,11 +1052,12 @@ void security_inode_free(struct inode *i
 }
 
 int security_dentry_init_security(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
-					u32 *ctxlen)
+				  const struct qstr *name,
+				  const char **xattr_name, void **ctx,
+				  u32 *ctxlen)
 {
 	return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode,
-				name, ctx, ctxlen);
+				name, xattr_name, ctx, ctxlen);
 }
 EXPORT_SYMBOL(security_dentry_init_security);
 
Index: redhat-linux/include/linux/lsm_hooks.h
===================================================================
--- redhat-linux.orig/include/linux/lsm_hooks.h	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/include/linux/lsm_hooks.h	2021-10-12 09:05:00.830399245 -0400
@@ -196,6 +196,9 @@
  *	@dentry dentry to use in calculating the context.
  *	@mode mode used to determine resource type.
  *	@name name of the last path component used to create file
+ *	@xattr_name pointer to place the pointer to security xattr name.
+ *		    Caller does not have to free the resulting pointer. Its
+ *		    a pointer to static string.
  *	@ctx pointer to place the pointer to the resulting context in.
  *	@ctxlen point to place the length of the resulting context.
  * @dentry_create_files_as:
Index: redhat-linux/include/linux/security.h
===================================================================
--- redhat-linux.orig/include/linux/security.h	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/include/linux/security.h	2021-10-06 15:20:57.751247170 -0400
@@ -317,8 +317,9 @@ int security_add_mnt_opt(const char *opt
 				int len, void **mnt_opts);
 int security_move_mount(const struct path *from_path, const struct path *to_path);
 int security_dentry_init_security(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
-					u32 *ctxlen);
+				  const struct qstr *name,
+				  const char **xattr_name, void **ctx,
+				  u32 *ctxlen);
 int security_dentry_create_files_as(struct dentry *dentry, int mode,
 					struct qstr *name,
 					const struct cred *old,
@@ -739,6 +740,7 @@ static inline void security_inode_free(s
 static inline int security_dentry_init_security(struct dentry *dentry,
 						 int mode,
 						 const struct qstr *name,
+						 const char **xattr_name,
 						 void **ctx,
 						 u32 *ctxlen)
 {
Index: redhat-linux/include/linux/lsm_hook_defs.h
===================================================================
--- redhat-linux.orig/include/linux/lsm_hook_defs.h	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/include/linux/lsm_hook_defs.h	2021-10-06 15:20:57.752247170 -0400
@@ -83,7 +83,8 @@ LSM_HOOK(int, 0, sb_add_mnt_opt, const c
 LSM_HOOK(int, 0, move_mount, const struct path *from_path,
 	 const struct path *to_path)
 LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,
-	 int mode, const struct qstr *name, void **ctx, u32 *ctxlen)
+	 int mode, const struct qstr *name, const char **xattr_name,
+	 void **ctx, u32 *ctxlen)
 LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode,
 	 struct qstr *name, const struct cred *old, struct cred *new)
 
Index: redhat-linux/fs/nfs/nfs4proc.c
===================================================================
--- redhat-linux.orig/fs/nfs/nfs4proc.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/fs/nfs/nfs4proc.c	2021-10-06 15:20:57.754247170 -0400
@@ -127,7 +127,8 @@ nfs4_label_init_security(struct inode *d
 		return NULL;
 
 	err = security_dentry_init_security(dentry, sattr->ia_mode,
-				&dentry->d_name, (void **)&label->label, &label->len);
+				&dentry->d_name, NULL,
+				(void **)&label->label, &label->len);
 	if (err == 0)
 		return label;
 
Index: redhat-linux/fs/ceph/xattr.c
===================================================================
--- redhat-linux.orig/fs/ceph/xattr.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/fs/ceph/xattr.c	2021-10-06 15:20:57.756247170 -0400
@@ -1311,7 +1311,7 @@ int ceph_security_init_secctx(struct den
 	int err;
 
 	err = security_dentry_init_security(dentry, mode, &dentry->d_name,
-					    &as_ctx->sec_ctx,
+					    &name, &as_ctx->sec_ctx,
 					    &as_ctx->sec_ctxlen);
 	if (err < 0) {
 		WARN_ON_ONCE(err != -EOPNOTSUPP);
@@ -1335,7 +1335,6 @@ int ceph_security_init_secctx(struct den
 	 * It only supports single security module and only selinux has
 	 * dentry_init_security hook.
 	 */
-	name = XATTR_NAME_SELINUX;
 	name_len = strlen(name);
 	err = ceph_pagelist_reserve(pagelist,
 				    4 * 2 + name_len + as_ctx->sec_ctxlen);

[Virtio-fs] [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Vivek Goyal]

Right now security_dentry_init_security() only supports single security
label and is used by SELinux only. There are two users of of this hook,
namely ceph and nfs.

NFS does not care about xattr name. Ceph hardcodes the xattr name to
security.selinux (XATTR_NAME_SELINUX).

I am making changes to fuse/virtiofs to send security label to virtiofsd
and I need to send xattr name as well. I also hardcoded the name of
xattr to security.selinux.

Stephen Smalley suggested that it probably is a good idea to modify
security_dentry_init_security() to also return name of xattr so that
we can avoid this hardcoding in the callers.

This patch adds a new parameter "const char **xattr_name" to
security_dentry_init_security() and LSM puts the name of xattr
too if caller asked for it (xattr_name != NULL).

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
---

Changes since v1:
- Updated comment to make it clear caller does not have to free the
  xattr_name. (Jeff Layton).
- Captured Jeff's Reviewed-by ack.

I have tested this patch with virtiofs and compile tested for ceph and nfs.

NFS changes are trivial. Looking for an ack from NFS maintainers.

---
 fs/ceph/xattr.c               |    3 +--
 fs/nfs/nfs4proc.c             |    3 ++-
 include/linux/lsm_hook_defs.h |    3 ++-
 include/linux/lsm_hooks.h     |    3 +++
 include/linux/security.h      |    6 ++++--
 security/security.c           |    7 ++++---
 security/selinux/hooks.c      |    6 +++++-
 7 files changed, 21 insertions(+), 10 deletions(-)

Index: redhat-linux/security/selinux/hooks.c
===================================================================
--- redhat-linux.orig/security/selinux/hooks.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/security/selinux/hooks.c	2021-10-06 15:20:57.745247170 -0400
@@ -2948,7 +2948,8 @@ static void selinux_inode_free_security(
 }
 
 static int selinux_dentry_init_security(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
+					const struct qstr *name,
+					const char **xattr_name, void **ctx,
 					u32 *ctxlen)
 {
 	u32 newsid;
@@ -2961,6 +2962,9 @@ static int selinux_dentry_init_security(
 	if (rc)
 		return rc;
 
+	if (xattr_name)
+		*xattr_name = XATTR_NAME_SELINUX;
+
 	return security_sid_to_context(&selinux_state, newsid, (char **)ctx,
 				       ctxlen);
 }
Index: redhat-linux/security/security.c
===================================================================
--- redhat-linux.orig/security/security.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/security/security.c	2021-10-06 15:20:57.749247170 -0400
@@ -1052,11 +1052,12 @@ void security_inode_free(struct inode *i
 }
 
 int security_dentry_init_security(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
-					u32 *ctxlen)
+				  const struct qstr *name,
+				  const char **xattr_name, void **ctx,
+				  u32 *ctxlen)
 {
 	return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode,
-				name, ctx, ctxlen);
+				name, xattr_name, ctx, ctxlen);
 }
 EXPORT_SYMBOL(security_dentry_init_security);
 
Index: redhat-linux/include/linux/lsm_hooks.h
===================================================================
--- redhat-linux.orig/include/linux/lsm_hooks.h	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/include/linux/lsm_hooks.h	2021-10-12 09:05:00.830399245 -0400
@@ -196,6 +196,9 @@
  *	@dentry dentry to use in calculating the context.
  *	@mode mode used to determine resource type.
  *	@name name of the last path component used to create file
+ *	@xattr_name pointer to place the pointer to security xattr name.
+ *		    Caller does not have to free the resulting pointer. Its
+ *		    a pointer to static string.
  *	@ctx pointer to place the pointer to the resulting context in.
  *	@ctxlen point to place the length of the resulting context.
  * @dentry_create_files_as:
Index: redhat-linux/include/linux/security.h
===================================================================
--- redhat-linux.orig/include/linux/security.h	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/include/linux/security.h	2021-10-06 15:20:57.751247170 -0400
@@ -317,8 +317,9 @@ int security_add_mnt_opt(const char *opt
 				int len, void **mnt_opts);
 int security_move_mount(const struct path *from_path, const struct path *to_path);
 int security_dentry_init_security(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
-					u32 *ctxlen);
+				  const struct qstr *name,
+				  const char **xattr_name, void **ctx,
+				  u32 *ctxlen);
 int security_dentry_create_files_as(struct dentry *dentry, int mode,
 					struct qstr *name,
 					const struct cred *old,
@@ -739,6 +740,7 @@ static inline void security_inode_free(s
 static inline int security_dentry_init_security(struct dentry *dentry,
 						 int mode,
 						 const struct qstr *name,
+						 const char **xattr_name,
 						 void **ctx,
 						 u32 *ctxlen)
 {
Index: redhat-linux/include/linux/lsm_hook_defs.h
===================================================================
--- redhat-linux.orig/include/linux/lsm_hook_defs.h	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/include/linux/lsm_hook_defs.h	2021-10-06 15:20:57.752247170 -0400
@@ -83,7 +83,8 @@ LSM_HOOK(int, 0, sb_add_mnt_opt, const c
 LSM_HOOK(int, 0, move_mount, const struct path *from_path,
 	 const struct path *to_path)
 LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,
-	 int mode, const struct qstr *name, void **ctx, u32 *ctxlen)
+	 int mode, const struct qstr *name, const char **xattr_name,
+	 void **ctx, u32 *ctxlen)
 LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode,
 	 struct qstr *name, const struct cred *old, struct cred *new)
 
Index: redhat-linux/fs/nfs/nfs4proc.c
===================================================================
--- redhat-linux.orig/fs/nfs/nfs4proc.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/fs/nfs/nfs4proc.c	2021-10-06 15:20:57.754247170 -0400
@@ -127,7 +127,8 @@ nfs4_label_init_security(struct inode *d
 		return NULL;
 
 	err = security_dentry_init_security(dentry, sattr->ia_mode,
-				&dentry->d_name, (void **)&label->label, &label->len);
+				&dentry->d_name, NULL,
+				(void **)&label->label, &label->len);
 	if (err == 0)
 		return label;
 
Index: redhat-linux/fs/ceph/xattr.c
===================================================================
--- redhat-linux.orig/fs/ceph/xattr.c	2021-10-04 15:40:28.978453324 -0400
+++ redhat-linux/fs/ceph/xattr.c	2021-10-06 15:20:57.756247170 -0400
@@ -1311,7 +1311,7 @@ int ceph_security_init_secctx(struct den
 	int err;
 
 	err = security_dentry_init_security(dentry, mode, &dentry->d_name,
-					    &as_ctx->sec_ctx,
+					    &name, &as_ctx->sec_ctx,
 					    &as_ctx->sec_ctxlen);
 	if (err < 0) {
 		WARN_ON_ONCE(err != -EOPNOTSUPP);
@@ -1335,7 +1335,6 @@ int ceph_security_init_secctx(struct den
 	 * It only supports single security module and only selinux has
 	 * dentry_init_security hook.
 	 */
-	name = XATTR_NAME_SELINUX;
 	name_len = strlen(name);
 	err = ceph_pagelist_reserve(pagelist,
 				    4 * 2 + name_len + as_ctx->sec_ctxlen);

Re: [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Christian Brauner]

On Tue, Oct 12, 2021 at 09:23:07AM -0400, Vivek Goyal wrote:
> Right now security_dentry_init_security() only supports single security
> label and is used by SELinux only. There are two users of of this hook,
> namely ceph and nfs.
> 
> NFS does not care about xattr name. Ceph hardcodes the xattr name to
> security.selinux (XATTR_NAME_SELINUX).
> 
> I am making changes to fuse/virtiofs to send security label to virtiofsd
> and I need to send xattr name as well. I also hardcoded the name of
> xattr to security.selinux.
> 
> Stephen Smalley suggested that it probably is a good idea to modify
> security_dentry_init_security() to also return name of xattr so that
> we can avoid this hardcoding in the callers.
> 
> This patch adds a new parameter "const char **xattr_name" to
> security_dentry_init_security() and LSM puts the name of xattr
> too if caller asked for it (xattr_name != NULL).
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> ---

Looks good to me.
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>

Re: [Virtio-fs] [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Christian Brauner]

On Tue, Oct 12, 2021 at 09:23:07AM -0400, Vivek Goyal wrote:
> Right now security_dentry_init_security() only supports single security
> label and is used by SELinux only. There are two users of of this hook,
> namely ceph and nfs.
> 
> NFS does not care about xattr name. Ceph hardcodes the xattr name to
> security.selinux (XATTR_NAME_SELINUX).
> 
> I am making changes to fuse/virtiofs to send security label to virtiofsd
> and I need to send xattr name as well. I also hardcoded the name of
> xattr to security.selinux.
> 
> Stephen Smalley suggested that it probably is a good idea to modify
> security_dentry_init_security() to also return name of xattr so that
> we can avoid this hardcoding in the callers.
> 
> This patch adds a new parameter "const char **xattr_name" to
> security_dentry_init_security() and LSM puts the name of xattr
> too if caller asked for it (xattr_name != NULL).
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> ---

Looks good to me.
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>

Re: [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Vivek Goyal]

Hi James,

I am assuming this patch will need to be routed through security tree.
Can you please consider it for inclusion.

Thanks
Vivek

On Tue, Oct 12, 2021 at 09:23:07AM -0400, Vivek Goyal wrote:
> Right now security_dentry_init_security() only supports single security
> label and is used by SELinux only. There are two users of of this hook,
> namely ceph and nfs.
> 
> NFS does not care about xattr name. Ceph hardcodes the xattr name to
> security.selinux (XATTR_NAME_SELINUX).
> 
> I am making changes to fuse/virtiofs to send security label to virtiofsd
> and I need to send xattr name as well. I also hardcoded the name of
> xattr to security.selinux.
> 
> Stephen Smalley suggested that it probably is a good idea to modify
> security_dentry_init_security() to also return name of xattr so that
> we can avoid this hardcoding in the callers.
> 
> This patch adds a new parameter "const char **xattr_name" to
> security_dentry_init_security() and LSM puts the name of xattr
> too if caller asked for it (xattr_name != NULL).
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> ---
> 
> Changes since v1:
> - Updated comment to make it clear caller does not have to free the
>   xattr_name. (Jeff Layton).
> - Captured Jeff's Reviewed-by ack.
> 
> I have tested this patch with virtiofs and compile tested for ceph and nfs.
> 
> NFS changes are trivial. Looking for an ack from NFS maintainers.
> 
> ---
>  fs/ceph/xattr.c               |    3 +--
>  fs/nfs/nfs4proc.c             |    3 ++-
>  include/linux/lsm_hook_defs.h |    3 ++-
>  include/linux/lsm_hooks.h     |    3 +++
>  include/linux/security.h      |    6 ++++--
>  security/security.c           |    7 ++++---
>  security/selinux/hooks.c      |    6 +++++-
>  7 files changed, 21 insertions(+), 10 deletions(-)
> 
> Index: redhat-linux/security/selinux/hooks.c
> ===================================================================
> --- redhat-linux.orig/security/selinux/hooks.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/security/selinux/hooks.c	2021-10-06 15:20:57.745247170 -0400
> @@ -2948,7 +2948,8 @@ static void selinux_inode_free_security(
>  }
>  
>  static int selinux_dentry_init_security(struct dentry *dentry, int mode,
> -					const struct qstr *name, void **ctx,
> +					const struct qstr *name,
> +					const char **xattr_name, void **ctx,
>  					u32 *ctxlen)
>  {
>  	u32 newsid;
> @@ -2961,6 +2962,9 @@ static int selinux_dentry_init_security(
>  	if (rc)
>  		return rc;
>  
> +	if (xattr_name)
> +		*xattr_name = XATTR_NAME_SELINUX;
> +
>  	return security_sid_to_context(&selinux_state, newsid, (char **)ctx,
>  				       ctxlen);
>  }
> Index: redhat-linux/security/security.c
> ===================================================================
> --- redhat-linux.orig/security/security.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/security/security.c	2021-10-06 15:20:57.749247170 -0400
> @@ -1052,11 +1052,12 @@ void security_inode_free(struct inode *i
>  }
>  
>  int security_dentry_init_security(struct dentry *dentry, int mode,
> -					const struct qstr *name, void **ctx,
> -					u32 *ctxlen)
> +				  const struct qstr *name,
> +				  const char **xattr_name, void **ctx,
> +				  u32 *ctxlen)
>  {
>  	return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode,
> -				name, ctx, ctxlen);
> +				name, xattr_name, ctx, ctxlen);
>  }
>  EXPORT_SYMBOL(security_dentry_init_security);
>  
> Index: redhat-linux/include/linux/lsm_hooks.h
> ===================================================================
> --- redhat-linux.orig/include/linux/lsm_hooks.h	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/include/linux/lsm_hooks.h	2021-10-12 09:05:00.830399245 -0400
> @@ -196,6 +196,9 @@
>   *	@dentry dentry to use in calculating the context.
>   *	@mode mode used to determine resource type.
>   *	@name name of the last path component used to create file
> + *	@xattr_name pointer to place the pointer to security xattr name.
> + *		    Caller does not have to free the resulting pointer. Its
> + *		    a pointer to static string.
>   *	@ctx pointer to place the pointer to the resulting context in.
>   *	@ctxlen point to place the length of the resulting context.
>   * @dentry_create_files_as:
> Index: redhat-linux/include/linux/security.h
> ===================================================================
> --- redhat-linux.orig/include/linux/security.h	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/include/linux/security.h	2021-10-06 15:20:57.751247170 -0400
> @@ -317,8 +317,9 @@ int security_add_mnt_opt(const char *opt
>  				int len, void **mnt_opts);
>  int security_move_mount(const struct path *from_path, const struct path *to_path);
>  int security_dentry_init_security(struct dentry *dentry, int mode,
> -					const struct qstr *name, void **ctx,
> -					u32 *ctxlen);
> +				  const struct qstr *name,
> +				  const char **xattr_name, void **ctx,
> +				  u32 *ctxlen);
>  int security_dentry_create_files_as(struct dentry *dentry, int mode,
>  					struct qstr *name,
>  					const struct cred *old,
> @@ -739,6 +740,7 @@ static inline void security_inode_free(s
>  static inline int security_dentry_init_security(struct dentry *dentry,
>  						 int mode,
>  						 const struct qstr *name,
> +						 const char **xattr_name,
>  						 void **ctx,
>  						 u32 *ctxlen)
>  {
> Index: redhat-linux/include/linux/lsm_hook_defs.h
> ===================================================================
> --- redhat-linux.orig/include/linux/lsm_hook_defs.h	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/include/linux/lsm_hook_defs.h	2021-10-06 15:20:57.752247170 -0400
> @@ -83,7 +83,8 @@ LSM_HOOK(int, 0, sb_add_mnt_opt, const c
>  LSM_HOOK(int, 0, move_mount, const struct path *from_path,
>  	 const struct path *to_path)
>  LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,
> -	 int mode, const struct qstr *name, void **ctx, u32 *ctxlen)
> +	 int mode, const struct qstr *name, const char **xattr_name,
> +	 void **ctx, u32 *ctxlen)
>  LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode,
>  	 struct qstr *name, const struct cred *old, struct cred *new)
>  
> Index: redhat-linux/fs/nfs/nfs4proc.c
> ===================================================================
> --- redhat-linux.orig/fs/nfs/nfs4proc.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/fs/nfs/nfs4proc.c	2021-10-06 15:20:57.754247170 -0400
> @@ -127,7 +127,8 @@ nfs4_label_init_security(struct inode *d
>  		return NULL;
>  
>  	err = security_dentry_init_security(dentry, sattr->ia_mode,
> -				&dentry->d_name, (void **)&label->label, &label->len);
> +				&dentry->d_name, NULL,
> +				(void **)&label->label, &label->len);
>  	if (err == 0)
>  		return label;
>  
> Index: redhat-linux/fs/ceph/xattr.c
> ===================================================================
> --- redhat-linux.orig/fs/ceph/xattr.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/fs/ceph/xattr.c	2021-10-06 15:20:57.756247170 -0400
> @@ -1311,7 +1311,7 @@ int ceph_security_init_secctx(struct den
>  	int err;
>  
>  	err = security_dentry_init_security(dentry, mode, &dentry->d_name,
> -					    &as_ctx->sec_ctx,
> +					    &name, &as_ctx->sec_ctx,
>  					    &as_ctx->sec_ctxlen);
>  	if (err < 0) {
>  		WARN_ON_ONCE(err != -EOPNOTSUPP);
> @@ -1335,7 +1335,6 @@ int ceph_security_init_secctx(struct den
>  	 * It only supports single security module and only selinux has
>  	 * dentry_init_security hook.
>  	 */
> -	name = XATTR_NAME_SELINUX;
>  	name_len = strlen(name);
>  	err = ceph_pagelist_reserve(pagelist,
>  				    4 * 2 + name_len + as_ctx->sec_ctxlen);
> 

Re: [Virtio-fs] [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Vivek Goyal]

Hi James,

I am assuming this patch will need to be routed through security tree.
Can you please consider it for inclusion.

Thanks
Vivek

On Tue, Oct 12, 2021 at 09:23:07AM -0400, Vivek Goyal wrote:
> Right now security_dentry_init_security() only supports single security
> label and is used by SELinux only. There are two users of of this hook,
> namely ceph and nfs.
> 
> NFS does not care about xattr name. Ceph hardcodes the xattr name to
> security.selinux (XATTR_NAME_SELINUX).
> 
> I am making changes to fuse/virtiofs to send security label to virtiofsd
> and I need to send xattr name as well. I also hardcoded the name of
> xattr to security.selinux.
> 
> Stephen Smalley suggested that it probably is a good idea to modify
> security_dentry_init_security() to also return name of xattr so that
> we can avoid this hardcoding in the callers.
> 
> This patch adds a new parameter "const char **xattr_name" to
> security_dentry_init_security() and LSM puts the name of xattr
> too if caller asked for it (xattr_name != NULL).
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> ---
> 
> Changes since v1:
> - Updated comment to make it clear caller does not have to free the
>   xattr_name. (Jeff Layton).
> - Captured Jeff's Reviewed-by ack.
> 
> I have tested this patch with virtiofs and compile tested for ceph and nfs.
> 
> NFS changes are trivial. Looking for an ack from NFS maintainers.
> 
> ---
>  fs/ceph/xattr.c               |    3 +--
>  fs/nfs/nfs4proc.c             |    3 ++-
>  include/linux/lsm_hook_defs.h |    3 ++-
>  include/linux/lsm_hooks.h     |    3 +++
>  include/linux/security.h      |    6 ++++--
>  security/security.c           |    7 ++++---
>  security/selinux/hooks.c      |    6 +++++-
>  7 files changed, 21 insertions(+), 10 deletions(-)
> 
> Index: redhat-linux/security/selinux/hooks.c
> ===================================================================
> --- redhat-linux.orig/security/selinux/hooks.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/security/selinux/hooks.c	2021-10-06 15:20:57.745247170 -0400
> @@ -2948,7 +2948,8 @@ static void selinux_inode_free_security(
>  }
>  
>  static int selinux_dentry_init_security(struct dentry *dentry, int mode,
> -					const struct qstr *name, void **ctx,
> +					const struct qstr *name,
> +					const char **xattr_name, void **ctx,
>  					u32 *ctxlen)
>  {
>  	u32 newsid;
> @@ -2961,6 +2962,9 @@ static int selinux_dentry_init_security(
>  	if (rc)
>  		return rc;
>  
> +	if (xattr_name)
> +		*xattr_name = XATTR_NAME_SELINUX;
> +
>  	return security_sid_to_context(&selinux_state, newsid, (char **)ctx,
>  				       ctxlen);
>  }
> Index: redhat-linux/security/security.c
> ===================================================================
> --- redhat-linux.orig/security/security.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/security/security.c	2021-10-06 15:20:57.749247170 -0400
> @@ -1052,11 +1052,12 @@ void security_inode_free(struct inode *i
>  }
>  
>  int security_dentry_init_security(struct dentry *dentry, int mode,
> -					const struct qstr *name, void **ctx,
> -					u32 *ctxlen)
> +				  const struct qstr *name,
> +				  const char **xattr_name, void **ctx,
> +				  u32 *ctxlen)
>  {
>  	return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode,
> -				name, ctx, ctxlen);
> +				name, xattr_name, ctx, ctxlen);
>  }
>  EXPORT_SYMBOL(security_dentry_init_security);
>  
> Index: redhat-linux/include/linux/lsm_hooks.h
> ===================================================================
> --- redhat-linux.orig/include/linux/lsm_hooks.h	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/include/linux/lsm_hooks.h	2021-10-12 09:05:00.830399245 -0400
> @@ -196,6 +196,9 @@
>   *	@dentry dentry to use in calculating the context.
>   *	@mode mode used to determine resource type.
>   *	@name name of the last path component used to create file
> + *	@xattr_name pointer to place the pointer to security xattr name.
> + *		    Caller does not have to free the resulting pointer. Its
> + *		    a pointer to static string.
>   *	@ctx pointer to place the pointer to the resulting context in.
>   *	@ctxlen point to place the length of the resulting context.
>   * @dentry_create_files_as:
> Index: redhat-linux/include/linux/security.h
> ===================================================================
> --- redhat-linux.orig/include/linux/security.h	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/include/linux/security.h	2021-10-06 15:20:57.751247170 -0400
> @@ -317,8 +317,9 @@ int security_add_mnt_opt(const char *opt
>  				int len, void **mnt_opts);
>  int security_move_mount(const struct path *from_path, const struct path *to_path);
>  int security_dentry_init_security(struct dentry *dentry, int mode,
> -					const struct qstr *name, void **ctx,
> -					u32 *ctxlen);
> +				  const struct qstr *name,
> +				  const char **xattr_name, void **ctx,
> +				  u32 *ctxlen);
>  int security_dentry_create_files_as(struct dentry *dentry, int mode,
>  					struct qstr *name,
>  					const struct cred *old,
> @@ -739,6 +740,7 @@ static inline void security_inode_free(s
>  static inline int security_dentry_init_security(struct dentry *dentry,
>  						 int mode,
>  						 const struct qstr *name,
> +						 const char **xattr_name,
>  						 void **ctx,
>  						 u32 *ctxlen)
>  {
> Index: redhat-linux/include/linux/lsm_hook_defs.h
> ===================================================================
> --- redhat-linux.orig/include/linux/lsm_hook_defs.h	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/include/linux/lsm_hook_defs.h	2021-10-06 15:20:57.752247170 -0400
> @@ -83,7 +83,8 @@ LSM_HOOK(int, 0, sb_add_mnt_opt, const c
>  LSM_HOOK(int, 0, move_mount, const struct path *from_path,
>  	 const struct path *to_path)
>  LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,
> -	 int mode, const struct qstr *name, void **ctx, u32 *ctxlen)
> +	 int mode, const struct qstr *name, const char **xattr_name,
> +	 void **ctx, u32 *ctxlen)
>  LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode,
>  	 struct qstr *name, const struct cred *old, struct cred *new)
>  
> Index: redhat-linux/fs/nfs/nfs4proc.c
> ===================================================================
> --- redhat-linux.orig/fs/nfs/nfs4proc.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/fs/nfs/nfs4proc.c	2021-10-06 15:20:57.754247170 -0400
> @@ -127,7 +127,8 @@ nfs4_label_init_security(struct inode *d
>  		return NULL;
>  
>  	err = security_dentry_init_security(dentry, sattr->ia_mode,
> -				&dentry->d_name, (void **)&label->label, &label->len);
> +				&dentry->d_name, NULL,
> +				(void **)&label->label, &label->len);
>  	if (err == 0)
>  		return label;
>  
> Index: redhat-linux/fs/ceph/xattr.c
> ===================================================================
> --- redhat-linux.orig/fs/ceph/xattr.c	2021-10-04 15:40:28.978453324 -0400
> +++ redhat-linux/fs/ceph/xattr.c	2021-10-06 15:20:57.756247170 -0400
> @@ -1311,7 +1311,7 @@ int ceph_security_init_secctx(struct den
>  	int err;
>  
>  	err = security_dentry_init_security(dentry, mode, &dentry->d_name,
> -					    &as_ctx->sec_ctx,
> +					    &name, &as_ctx->sec_ctx,
>  					    &as_ctx->sec_ctxlen);
>  	if (err < 0) {
>  		WARN_ON_ONCE(err != -EOPNOTSUPP);
> @@ -1335,7 +1335,6 @@ int ceph_security_init_secctx(struct den
>  	 * It only supports single security module and only selinux has
>  	 * dentry_init_security hook.
>  	 */
> -	name = XATTR_NAME_SELINUX;
>  	name_len = strlen(name);
>  	err = ceph_pagelist_reserve(pagelist,
>  				    4 * 2 + name_len + as_ctx->sec_ctxlen);
> 

Re: [PATCH v2] security: Return xattr name from security_dentry_init_security()

[James Morris]

On Mon, 18 Oct 2021, Vivek Goyal wrote:

> Hi James,
> 
> I am assuming this patch will need to be routed through security tree.
> Can you please consider it for inclusion.
> 

I'm happy for this to go via Paul's tree as it impacts SELinux and is 
fairly minor in scope.


Acked-by: James Morris <jamorris@linux.microsoft.com>


-- 
James Morris
<jmorris@namei.org>

Re: [Virtio-fs] [PATCH v2] security: Return xattr name from security_dentry_init_security()

[James Morris]

On Mon, 18 Oct 2021, Vivek Goyal wrote:

> Hi James,
> 
> I am assuming this patch will need to be routed through security tree.
> Can you please consider it for inclusion.
> 

I'm happy for this to go via Paul's tree as it impacts SELinux and is 
fairly minor in scope.


Acked-by: James Morris <jamorris@linux.microsoft.com>


-- 
James Morris
<jmorris@namei.org>

Re: [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Paul Moore]

On Tue, Oct 19, 2021 at 5:02 PM James Morris <jmorris@namei.org> wrote:
>
> On Mon, 18 Oct 2021, Vivek Goyal wrote:
>
> > Hi James,
> >
> > I am assuming this patch will need to be routed through security tree.
> > Can you please consider it for inclusion.
>
> I'm happy for this to go via Paul's tree as it impacts SELinux and is
> fairly minor in scope.

I'll take a look tomorrow, I ended up spending most of my day today
chasing a 32-bit MIPS (!!) bug in libseccomp and now it's dinner time.

-- 
paul moore
www.paul-moore.com

Re: [Virtio-fs] [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Paul Moore]

On Tue, Oct 19, 2021 at 5:02 PM James Morris <jmorris@namei.org> wrote:
>
> On Mon, 18 Oct 2021, Vivek Goyal wrote:
>
> > Hi James,
> >
> > I am assuming this patch will need to be routed through security tree.
> > Can you please consider it for inclusion.
>
> I'm happy for this to go via Paul's tree as it impacts SELinux and is
> fairly minor in scope.

I'll take a look tomorrow, I ended up spending most of my day today
chasing a 32-bit MIPS (!!) bug in libseccomp and now it's dinner time.

-- 
paul moore
www.paul-moore.com

Re: [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Paul Moore]

On Tue, Oct 12, 2021 at 9:23 AM Vivek Goyal <vgoyal@redhat.com> wrote:
>
> Right now security_dentry_init_security() only supports single security
> label and is used by SELinux only. There are two users of of this hook,
> namely ceph and nfs.
>
> NFS does not care about xattr name. Ceph hardcodes the xattr name to
> security.selinux (XATTR_NAME_SELINUX).
>
> I am making changes to fuse/virtiofs to send security label to virtiofsd
> and I need to send xattr name as well. I also hardcoded the name of
> xattr to security.selinux.
>
> Stephen Smalley suggested that it probably is a good idea to modify
> security_dentry_init_security() to also return name of xattr so that
> we can avoid this hardcoding in the callers.
>
> This patch adds a new parameter "const char **xattr_name" to
> security_dentry_init_security() and LSM puts the name of xattr
> too if caller asked for it (xattr_name != NULL).
>
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> ---
>
> Changes since v1:
> - Updated comment to make it clear caller does not have to free the
>   xattr_name. (Jeff Layton).
> - Captured Jeff's Reviewed-by ack.
>
> I have tested this patch with virtiofs and compile tested for ceph and nfs.
>
> NFS changes are trivial. Looking for an ack from NFS maintainers.
>
> ---
>  fs/ceph/xattr.c               |    3 +--
>  fs/nfs/nfs4proc.c             |    3 ++-
>  include/linux/lsm_hook_defs.h |    3 ++-
>  include/linux/lsm_hooks.h     |    3 +++
>  include/linux/security.h      |    6 ++++--
>  security/security.c           |    7 ++++---
>  security/selinux/hooks.c      |    6 +++++-
>  7 files changed, 21 insertions(+), 10 deletions(-)

This looks fine to me and considering the trivial nature of the NFS
changes I'm okay with merging this without an explicit ACK from the
NFS folks.  Similarly, I generally dislike merging new functionality
once we hit -rc6, but this is trivial enough that I think it's okay;
I'm merging this into selinux/next now, thanks everyone.

-- 
paul moore
www.paul-moore.com

Re: [Virtio-fs] [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Paul Moore]

On Tue, Oct 12, 2021 at 9:23 AM Vivek Goyal <vgoyal@redhat.com> wrote:
>
> Right now security_dentry_init_security() only supports single security
> label and is used by SELinux only. There are two users of of this hook,
> namely ceph and nfs.
>
> NFS does not care about xattr name. Ceph hardcodes the xattr name to
> security.selinux (XATTR_NAME_SELINUX).
>
> I am making changes to fuse/virtiofs to send security label to virtiofsd
> and I need to send xattr name as well. I also hardcoded the name of
> xattr to security.selinux.
>
> Stephen Smalley suggested that it probably is a good idea to modify
> security_dentry_init_security() to also return name of xattr so that
> we can avoid this hardcoding in the callers.
>
> This patch adds a new parameter "const char **xattr_name" to
> security_dentry_init_security() and LSM puts the name of xattr
> too if caller asked for it (xattr_name != NULL).
>
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> Reviewed-by: Jeff Layton <jlayton@kernel.org>
> ---
>
> Changes since v1:
> - Updated comment to make it clear caller does not have to free the
>   xattr_name. (Jeff Layton).
> - Captured Jeff's Reviewed-by ack.
>
> I have tested this patch with virtiofs and compile tested for ceph and nfs.
>
> NFS changes are trivial. Looking for an ack from NFS maintainers.
>
> ---
>  fs/ceph/xattr.c               |    3 +--
>  fs/nfs/nfs4proc.c             |    3 ++-
>  include/linux/lsm_hook_defs.h |    3 ++-
>  include/linux/lsm_hooks.h     |    3 +++
>  include/linux/security.h      |    6 ++++--
>  security/security.c           |    7 ++++---
>  security/selinux/hooks.c      |    6 +++++-
>  7 files changed, 21 insertions(+), 10 deletions(-)

This looks fine to me and considering the trivial nature of the NFS
changes I'm okay with merging this without an explicit ACK from the
NFS folks.  Similarly, I generally dislike merging new functionality
once we hit -rc6, but this is trivial enough that I think it's okay;
I'm merging this into selinux/next now, thanks everyone.

-- 
paul moore
www.paul-moore.com

Re: [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Vivek Goyal]

On Wed, Oct 20, 2021 at 08:24:44AM -0400, Paul Moore wrote:
> On Tue, Oct 12, 2021 at 9:23 AM Vivek Goyal <vgoyal@redhat.com> wrote:
> >
> > Right now security_dentry_init_security() only supports single security
> > label and is used by SELinux only. There are two users of of this hook,
> > namely ceph and nfs.
> >
> > NFS does not care about xattr name. Ceph hardcodes the xattr name to
> > security.selinux (XATTR_NAME_SELINUX).
> >
> > I am making changes to fuse/virtiofs to send security label to virtiofsd
> > and I need to send xattr name as well. I also hardcoded the name of
> > xattr to security.selinux.
> >
> > Stephen Smalley suggested that it probably is a good idea to modify
> > security_dentry_init_security() to also return name of xattr so that
> > we can avoid this hardcoding in the callers.
> >
> > This patch adds a new parameter "const char **xattr_name" to
> > security_dentry_init_security() and LSM puts the name of xattr
> > too if caller asked for it (xattr_name != NULL).
> >
> > Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> > Reviewed-by: Jeff Layton <jlayton@kernel.org>
> > ---
> >
> > Changes since v1:
> > - Updated comment to make it clear caller does not have to free the
> >   xattr_name. (Jeff Layton).
> > - Captured Jeff's Reviewed-by ack.
> >
> > I have tested this patch with virtiofs and compile tested for ceph and nfs.
> >
> > NFS changes are trivial. Looking for an ack from NFS maintainers.
> >
> > ---
> >  fs/ceph/xattr.c               |    3 +--
> >  fs/nfs/nfs4proc.c             |    3 ++-
> >  include/linux/lsm_hook_defs.h |    3 ++-
> >  include/linux/lsm_hooks.h     |    3 +++
> >  include/linux/security.h      |    6 ++++--
> >  security/security.c           |    7 ++++---
> >  security/selinux/hooks.c      |    6 +++++-
> >  7 files changed, 21 insertions(+), 10 deletions(-)
> 
> This looks fine to me and considering the trivial nature of the NFS
> changes I'm okay with merging this without an explicit ACK from the
> NFS folks.  Similarly, I generally dislike merging new functionality
> once we hit -rc6, but this is trivial enough that I think it's okay;
> I'm merging this into selinux/next now, thanks everyone.

Thanks Paul. I agree that this a trivial fix with no functionality
change and probability of this breaking something is very very low.

Vivek

Re: [Virtio-fs] [PATCH v2] security: Return xattr name from security_dentry_init_security()

[Vivek Goyal]

On Wed, Oct 20, 2021 at 08:24:44AM -0400, Paul Moore wrote:
> On Tue, Oct 12, 2021 at 9:23 AM Vivek Goyal <vgoyal@redhat.com> wrote:
> >
> > Right now security_dentry_init_security() only supports single security
> > label and is used by SELinux only. There are two users of of this hook,
> > namely ceph and nfs.
> >
> > NFS does not care about xattr name. Ceph hardcodes the xattr name to
> > security.selinux (XATTR_NAME_SELINUX).
> >
> > I am making changes to fuse/virtiofs to send security label to virtiofsd
> > and I need to send xattr name as well. I also hardcoded the name of
> > xattr to security.selinux.
> >
> > Stephen Smalley suggested that it probably is a good idea to modify
> > security_dentry_init_security() to also return name of xattr so that
> > we can avoid this hardcoding in the callers.
> >
> > This patch adds a new parameter "const char **xattr_name" to
> > security_dentry_init_security() and LSM puts the name of xattr
> > too if caller asked for it (xattr_name != NULL).
> >
> > Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> > Reviewed-by: Jeff Layton <jlayton@kernel.org>
> > ---
> >
> > Changes since v1:
> > - Updated comment to make it clear caller does not have to free the
> >   xattr_name. (Jeff Layton).
> > - Captured Jeff's Reviewed-by ack.
> >
> > I have tested this patch with virtiofs and compile tested for ceph and nfs.
> >
> > NFS changes are trivial. Looking for an ack from NFS maintainers.
> >
> > ---
> >  fs/ceph/xattr.c               |    3 +--
> >  fs/nfs/nfs4proc.c             |    3 ++-
> >  include/linux/lsm_hook_defs.h |    3 ++-
> >  include/linux/lsm_hooks.h     |    3 +++
> >  include/linux/security.h      |    6 ++++--
> >  security/security.c           |    7 ++++---
> >  security/selinux/hooks.c      |    6 +++++-
> >  7 files changed, 21 insertions(+), 10 deletions(-)
> 
> This looks fine to me and considering the trivial nature of the NFS
> changes I'm okay with merging this without an explicit ACK from the
> NFS folks.  Similarly, I generally dislike merging new functionality
> once we hit -rc6, but this is trivial enough that I think it's okay;
> I'm merging this into selinux/next now, thanks everyone.

Thanks Paul. I agree that this a trivial fix with no functionality
change and probability of this breaking something is very very low.

Vivek