diff mbox series

[v3,4/5] LSM: lsm_context in security_dentry_init_security

Message ID 20241023212158.18718-5-casey@schaufler-ca.com (mailing list archive)
State Accepted
Delegated to: Paul Moore
Headers show
Series LSM: Replace secctx/len pairs with lsm_context | expand

Commit Message

Casey Schaufler Oct. 23, 2024, 9:21 p.m. UTC
Replace the (secctx,seclen) pointer pair with a single lsm_context
pointer to allow return of the LSM identifier along with the context
and context length. This allows security_release_secctx() to know how
to release the context. Callers have been modified to use or save the
returned data from the new structure.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: ceph-devel@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
---
 fs/ceph/super.h               |  3 +--
 fs/ceph/xattr.c               | 16 ++++++----------
 fs/fuse/dir.c                 | 35 ++++++++++++++++++-----------------
 fs/nfs/nfs4proc.c             | 20 ++++++++++++--------
 include/linux/lsm_hook_defs.h |  2 +-
 include/linux/security.h      | 26 +++-----------------------
 security/security.c           |  9 ++++-----
 security/selinux/hooks.c      |  9 +++++----
 8 files changed, 50 insertions(+), 70 deletions(-)

Comments

Paul Moore Oct. 31, 2024, 10:53 p.m. UTC | #1
On Oct 23, 2024 Casey Schaufler <casey@schaufler-ca.com> wrote:
> 
> Replace the (secctx,seclen) pointer pair with a single lsm_context
> pointer to allow return of the LSM identifier along with the context
> and context length. This allows security_release_secctx() to know how
> to release the context. Callers have been modified to use or save the
> returned data from the new structure.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: ceph-devel@vger.kernel.org
> Cc: linux-nfs@vger.kernel.org
> ---
>  fs/ceph/super.h               |  3 +--
>  fs/ceph/xattr.c               | 16 ++++++----------
>  fs/fuse/dir.c                 | 35 ++++++++++++++++++-----------------
>  fs/nfs/nfs4proc.c             | 20 ++++++++++++--------
>  include/linux/lsm_hook_defs.h |  2 +-
>  include/linux/security.h      | 26 +++-----------------------
>  security/security.c           |  9 ++++-----
>  security/selinux/hooks.c      |  9 +++++----
>  8 files changed, 50 insertions(+), 70 deletions(-)

See my note on patch 1/5, merging into lsm/dev.

--
paul-moore.com
diff mbox series

Patch

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 2508aa8950b7..c9fad8c825dd 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1133,8 +1133,7 @@  struct ceph_acl_sec_ctx {
 	void *acl;
 #endif
 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	void *sec_ctx;
-	u32 sec_ctxlen;
+	struct lsm_context lsmctx;
 #endif
 #ifdef CONFIG_FS_ENCRYPTION
 	struct ceph_fscrypt_auth *fscrypt_auth;
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index f7996770cc2c..0b9e1f385d31 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1383,8 +1383,7 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 	int err;
 
 	err = security_dentry_init_security(dentry, mode, &dentry->d_name,
-					    &name, &as_ctx->sec_ctx,
-					    &as_ctx->sec_ctxlen);
+					    &name, &as_ctx->lsmctx);
 	if (err < 0) {
 		WARN_ON_ONCE(err != -EOPNOTSUPP);
 		err = 0; /* do nothing */
@@ -1409,7 +1408,7 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 	 */
 	name_len = strlen(name);
 	err = ceph_pagelist_reserve(pagelist,
-				    4 * 2 + name_len + as_ctx->sec_ctxlen);
+				    4 * 2 + name_len + as_ctx->lsmctx.len);
 	if (err)
 		goto out;
 
@@ -1432,8 +1431,9 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 	ceph_pagelist_encode_32(pagelist, name_len);
 	ceph_pagelist_append(pagelist, name, name_len);
 
-	ceph_pagelist_encode_32(pagelist, as_ctx->sec_ctxlen);
-	ceph_pagelist_append(pagelist, as_ctx->sec_ctx, as_ctx->sec_ctxlen);
+	ceph_pagelist_encode_32(pagelist, as_ctx->lsmctx.len);
+	ceph_pagelist_append(pagelist, as_ctx->lsmctx.context,
+			     as_ctx->lsmctx.len);
 
 	err = 0;
 out:
@@ -1446,16 +1446,12 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 
 void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx)
 {
-#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	struct lsm_context scaff; /* scaffolding */
-#endif
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 	posix_acl_release(as_ctx->acl);
 	posix_acl_release(as_ctx->default_acl);
 #endif
 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0);
-	security_release_secctx(&scaff);
+	security_release_secctx(&as_ctx->lsmctx);
 #endif
 #ifdef CONFIG_FS_ENCRYPTION
 	kfree(as_ctx->fscrypt_auth);
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 54104dd48af7..eea4d0d27ce1 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -466,29 +466,29 @@  static int get_security_context(struct dentry *entry, umode_t mode,
 {
 	struct fuse_secctx *fctx;
 	struct fuse_secctx_header *header;
-	void *ctx = NULL, *ptr;
-	u32 ctxlen, total_len = sizeof(*header);
+	struct lsm_context lsmctx = { };
+	void *ptr;
+	u32 total_len = sizeof(*header);
 	int err, nr_ctx = 0;
-	const char *name;
+	const char *name = NULL;
 	size_t namelen;
 
 	err = security_dentry_init_security(entry, mode, &entry->d_name,
-					    &name, &ctx, &ctxlen);
-	if (err) {
-		if (err != -EOPNOTSUPP)
-			goto out_err;
-		/* No LSM is supporting this security hook. Ignore error */
-		ctxlen = 0;
-		ctx = NULL;
-	}
+					    &name, &lsmctx);
+
+	/* If no LSM is supporting this security hook ignore error */
+	if (err && err != -EOPNOTSUPP)
+		goto out_err;
 
-	if (ctxlen) {
+	if (lsmctx.len) {
 		nr_ctx = 1;
 		namelen = strlen(name) + 1;
 		err = -EIO;
-		if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || ctxlen > S32_MAX))
+		if (WARN_ON(namelen > XATTR_NAME_MAX + 1 ||
+		    lsmctx.len > S32_MAX))
 			goto out_err;
-		total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + ctxlen);
+		total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen +
+					    lsmctx.len);
 	}
 
 	err = -ENOMEM;
@@ -501,19 +501,20 @@  static int get_security_context(struct dentry *entry, umode_t mode,
 	ptr += sizeof(*header);
 	if (nr_ctx) {
 		fctx = ptr;
-		fctx->size = ctxlen;
+		fctx->size = lsmctx.len;
 		ptr += sizeof(*fctx);
 
 		strcpy(ptr, name);
 		ptr += namelen;
 
-		memcpy(ptr, ctx, ctxlen);
+		memcpy(ptr, lsmctx.context, lsmctx.len);
 	}
 	ext->size = total_len;
 	ext->value = header;
 	err = 0;
 out_err:
-	kfree(ctx);
+	if (nr_ctx)
+		security_release_secctx(&lsmctx);
 	return err;
 }
 
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 76776d716744..0b116ef3a752 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -114,6 +114,7 @@  static inline struct nfs4_label *
 nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
 	struct iattr *sattr, struct nfs4_label *label)
 {
+	struct lsm_context shim;
 	int err;
 
 	if (label == NULL)
@@ -128,21 +129,24 @@  nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
 	label->label = NULL;
 
 	err = security_dentry_init_security(dentry, sattr->ia_mode,
-				&dentry->d_name, NULL,
-				(void **)&label->label, &label->len);
-	if (err == 0)
-		return label;
+				&dentry->d_name, NULL, &shim);
+	if (err)
+		return NULL;
 
-	return NULL;
+	label->label = shim.context;
+	label->len = shim.len;
+	return label;
 }
 static inline void
 nfs4_label_release_security(struct nfs4_label *label)
 {
-	struct lsm_context scaff; /* scaffolding */
+	struct lsm_context shim;
 
 	if (label) {
-		lsmcontext_init(&scaff, label->label, label->len, 0);
-		security_release_secctx(&scaff);
+		shim.context = label->label;
+		shim.len = label->len;
+		shim.id = LSM_ID_UNDEF;
+		security_release_secctx(&shim);
 	}
 }
 static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 69e1076448c6..e2f1ce37c41e 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -83,7 +83,7 @@  LSM_HOOK(int, 0, move_mount, const struct path *from_path,
 	 const struct path *to_path)
 LSM_HOOK(int, -EOPNOTSUPP, dentry_init_security, struct dentry *dentry,
 	 int mode, const struct qstr *name, const char **xattr_name,
-	 void **ctx, u32 *ctxlen)
+	 struct lsm_context *cp)
 LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode,
 	 struct qstr *name, const struct cred *old, struct cred *new)
 
diff --git a/include/linux/security.h b/include/linux/security.h
index 7d0adc1833ab..3ad59666e56c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -237,25 +237,6 @@  struct lsm_context {
 	int	id;		/* Identifies the module */
 };
 
-/**
- * lsmcontext_init - initialize an lsmcontext structure.
- * @cp: Pointer to the context to initialize
- * @context: Initial context, or NULL
- * @size: Size of context, or 0
- * @id: Which LSM provided the context
- *
- * Fill in the lsmcontext from the provided information.
- * This is a scaffolding function that will be removed when
- * lsm_context integration is complete.
- */
-static inline void lsmcontext_init(struct lsm_context *cp, char *context,
-				   u32 size, int id)
-{
-	cp->id = id;
-	cp->context = context;
-	cp->len = size;
-}
-
 /*
  * Values used in the task_security_ops calls
  */
@@ -409,8 +390,8 @@  int security_sb_clone_mnt_opts(const struct super_block *oldsb,
 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,
-				  const char **xattr_name, void **ctx,
-				  u32 *ctxlen);
+				  const char **xattr_name,
+				  struct lsm_context *lsmcxt);
 int security_dentry_create_files_as(struct dentry *dentry, int mode,
 					struct qstr *name,
 					const struct cred *old,
@@ -883,8 +864,7 @@  static inline int security_dentry_init_security(struct dentry *dentry,
 						 int mode,
 						 const struct qstr *name,
 						 const char **xattr_name,
-						 void **ctx,
-						 u32 *ctxlen)
+						 struct lsm_context *lsmcxt)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index 4ca3c9e28b6f..1d57e4e1bceb 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1734,8 +1734,7 @@  void security_inode_free(struct inode *inode)
  * @mode: mode used to determine resource type
  * @name: name of the last path component
  * @xattr_name: name of the security/LSM xattr
- * @ctx: pointer to the resulting LSM context
- * @ctxlen: length of @ctx
+ * @lsmctx: pointer to the resulting LSM context
  *
  * Compute a context for a dentry as the inode is not yet available since NFSv4
  * has no label backed by an EA anyway.  It is important to note that
@@ -1745,11 +1744,11 @@  void security_inode_free(struct inode *inode)
  */
 int security_dentry_init_security(struct dentry *dentry, int mode,
 				  const struct qstr *name,
-				  const char **xattr_name, void **ctx,
-				  u32 *ctxlen)
+				  const char **xattr_name,
+				  struct lsm_context *lsmctx)
 {
 	return call_int_hook(dentry_init_security, dentry, mode, name,
-			     xattr_name, ctx, ctxlen);
+			     xattr_name, lsmctx);
 }
 EXPORT_SYMBOL(security_dentry_init_security);
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ce5e45abd8d3..79776a5e651d 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2869,8 +2869,8 @@  static void selinux_inode_free_security(struct inode *inode)
 
 static int selinux_dentry_init_security(struct dentry *dentry, int mode,
 					const struct qstr *name,
-					const char **xattr_name, void **ctx,
-					u32 *ctxlen)
+					const char **xattr_name,
+					struct lsm_context *cp)
 {
 	u32 newsid;
 	int rc;
@@ -2885,8 +2885,9 @@  static int selinux_dentry_init_security(struct dentry *dentry, int mode,
 	if (xattr_name)
 		*xattr_name = XATTR_NAME_SELINUX;
 
-	return security_sid_to_context(newsid, (char **)ctx,
-				       ctxlen);
+	cp->id = LSM_ID_SELINUX;
+	return security_sid_to_context(newsid, (char **)cp->context,
+				       &cp->len);
 }
 
 static int selinux_dentry_create_files_as(struct dentry *dentry, int mode,