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From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: keescook@chromium.org, john.johansen@canonical.com,
	penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com,
	sds@tycho.nsa.gov
Subject: [PATCH v11 17/25] LSM: Use lsmcontext in security_inode_getsecctx
Date: Wed, 13 Nov 2019 10:19:17 -0800
Message-ID: <20191113181925.2437-18-casey@schaufler-ca.com> (raw)
In-Reply-To: <20191113181925.2437-1-casey@schaufler-ca.com>

Change the security_inode_getsecctx() interface to fill
a lsmcontext structure instead of data and length pointers.
This provides the information about which LSM created the
context so that security_release_secctx() can use the
correct hook.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 fs/nfsd/nfs4xdr.c        | 23 +++++++++--------------
 include/linux/security.h |  5 +++--
 security/security.c      | 13 +++++++++++--
 3 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b17aad082bde..3e90d7c55c74 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2304,11 +2304,11 @@ nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
-			    void *context, int len)
+			    struct lsmcontext *context)
 {
 	__be32 *p;
 
-	p = xdr_reserve_space(xdr, len + 4 + 4 + 4);
+	p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4);
 	if (!p)
 		return nfserr_resource;
 
@@ -2318,13 +2318,13 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 	 */
 	*p++ = cpu_to_be32(0); /* lfs */
 	*p++ = cpu_to_be32(0); /* pi */
-	p = xdr_encode_opaque(p, context, len);
+	p = xdr_encode_opaque(p, context->context, context->len);
 	return 0;
 }
 #else
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
-			    void *context, int len)
+			    struct lsmcontext *context)
 { return 0; }
 #endif
 
@@ -2421,9 +2421,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	int err;
 	struct nfs4_acl *acl = NULL;
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	struct lsmcontext scaff; /* scaffolding */
-	void *context = NULL;
-	int contextlen;
+	struct lsmcontext context = { };
 #endif
 	bool contextsupport = false;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
@@ -2481,7 +2479,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	     bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
 		if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
 			err = security_inode_getsecctx(d_inode(dentry),
-						&context, &contextlen);
+						       &context);
 		else
 			err = -EOPNOTSUPP;
 		contextsupport = (err == 0);
@@ -2911,8 +2909,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
-		status = nfsd4_encode_security_label(xdr, rqstp, context,
-								contextlen);
+		status = nfsd4_encode_security_label(xdr, rqstp, &context);
 		if (status)
 			goto out;
 	}
@@ -2924,10 +2921,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 out:
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	if (context) {
-		lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
-		security_release_secctx(&scaff);
-	}
+	if (context.context)
+		security_release_secctx(&context);
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 	kfree(acl);
 	if (tempfh) {
diff --git a/include/linux/security.h b/include/linux/security.h
index 3e333104720d..5da16f97f2be 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -535,7 +535,7 @@ void security_release_secctx(struct lsmcontext *cp);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
 int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp);
 int security_locked_down(enum lockdown_reason what);
 #else /* CONFIG_SECURITY */
 
@@ -1360,7 +1360,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32
 {
 	return -EOPNOTSUPP;
 }
-static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static inline int security_inode_getsecctx(struct inode *inode,
+					   struct lsmcontext *cp)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index 6f43dafe1249..101063b00aeb 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2207,9 +2207,18 @@ int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 }
 EXPORT_SYMBOL(security_inode_setsecctx);
 
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp)
 {
-	return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, ctx, ctxlen);
+	struct security_hook_list *hp;
+
+	memset(cp, 0, sizeof(*cp));
+
+	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list) {
+		cp->slot = hp->lsmid->slot;
+		return hp->hook.inode_getsecctx(inode, (void **)&cp->context,
+						&cp->len);
+	}
+	return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(security_inode_getsecctx);
 
-- 
2.20.1


  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191113181925.2437-1-casey.ref@schaufler-ca.com>
2019-11-13 18:19 ` [PATCH v11 00/25] LSM: Module stacking for AppArmor Casey Schaufler
2019-11-13 18:19   ` [PATCH v11 01/25] LSM: Infrastructure management of the sock security Casey Schaufler
2019-11-21 18:39     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 02/25] LSM: Create and manage the lsmblob data structure Casey Schaufler
2019-11-21 18:40     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 03/25] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2019-11-21 18:40     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 04/25] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2019-11-21 18:41     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 05/25] net: Prepare UDS for security module stacking Casey Schaufler
2019-11-21 18:41     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 06/25] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2019-11-21 18:42     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 07/25] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2019-11-21 18:42     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 08/25] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2019-11-21 18:43     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 09/25] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2019-11-21 18:43     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 10/25] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2019-11-21 18:44     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 11/25] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2019-11-21 18:44     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 12/25] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2019-11-21 18:45     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 13/25] LSM: Specify which LSM to display Casey Schaufler
2019-11-13 18:19   ` [PATCH v11 14/25] LSM: Ensure the correct LSM context releaser Casey Schaufler
2019-11-21 19:00     ` John Johansen
2019-11-13 18:19   ` [PATCH v11 15/25] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2019-11-13 18:19   ` [PATCH v11 16/25] LSM: Use lsmcontext in security_dentry_init_security Casey Schaufler
2019-11-21 19:00     ` John Johansen
2019-11-13 18:19   ` Casey Schaufler [this message]
2019-11-13 17:56 [PATCH v11 00/25] LSM: Module stacking for AppArmor Casey Schaufler
2019-11-13 17:57 ` [PATCH v11 17/25] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2019-11-21  5:50   ` James Morris

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