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From: John Johansen <john.johansen@canonical.com>
To: Casey Schaufler <casey@schaufler-ca.com>,
	casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: keescook@chromium.org, penguin-kernel@i-love.sakura.ne.jp,
	paul@paul-moore.com, sds@tycho.nsa.gov
Subject: Re: [PATCH v4 19/23] LSM: Use lsmcontext in security_inode_getsecctx
Date: Thu, 27 Jun 2019 14:36:56 -0700	[thread overview]
Message-ID: <5d14cce0-c3ce-62bc-74a7-3020266ebda1@canonical.com> (raw)
In-Reply-To: <20190626192234.11725-20-casey@schaufler-ca.com>

On 6/26/19 12:22 PM, Casey Schaufler wrote:
> 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. A lsmcontext is used within kernfs to store
> the security information as well.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

Reviewed-by: John Johansen <john.johansen@canonical.com>


> ---
>  fs/kernfs/dir.c             |  8 ++------
>  fs/kernfs/inode.c           | 34 ++++++++++++----------------------
>  fs/kernfs/kernfs-internal.h |  3 +--
>  fs/nfsd/nfs4xdr.c           | 23 +++++++++--------------
>  include/linux/security.h    |  5 +++--
>  security/security.c         | 14 ++++++++++++--
>  6 files changed, 39 insertions(+), 48 deletions(-)
> 
> diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
> index 92afad387237..1d000289d8b7 100644
> --- a/fs/kernfs/dir.c
> +++ b/fs/kernfs/dir.c
> @@ -532,12 +532,8 @@ void kernfs_put(struct kernfs_node *kn)
>  	kfree_const(kn->name);
>  
>  	if (kn->iattr) {
> -		struct lsmcontext scaff; /* scaffolding */
> -		if (kn->iattr->ia_secdata) {
> -			lsmcontext_init(&scaff, kn->iattr->ia_secdata,
> -					kn->iattr->ia_secdata_len, 0);
> -			security_release_secctx(&scaff);
> -		}
> +		if (kn->iattr->ia_context.context)
> +			security_release_secctx(&kn->iattr->ia_context);
>  		simple_xattrs_free(&kn->iattr->xattrs);
>  		kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
>  	}
> diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
> index 02cde9dac5ee..ffbf7863306d 100644
> --- a/fs/kernfs/inode.c
> +++ b/fs/kernfs/inode.c
> @@ -135,21 +135,14 @@ int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
>  	return error;
>  }
>  
> -static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata,
> -				  u32 *secdata_len)
> +static void kernfs_node_setsecdata(struct kernfs_iattrs *attrs,
> +				   struct lsmcontext *cp)
>  {
> -	void *old_secdata;
> -	size_t old_secdata_len;
> +	struct lsmcontext old_context;
>  
> -	old_secdata = attrs->ia_secdata;
> -	old_secdata_len = attrs->ia_secdata_len;
> -
> -	attrs->ia_secdata = *secdata;
> -	attrs->ia_secdata_len = *secdata_len;
> -
> -	*secdata = old_secdata;
> -	*secdata_len = old_secdata_len;
> -	return 0;
> +	old_context = attrs->ia_context;
> +	attrs->ia_context = *cp;
> +	*cp = old_context;
>  }
>  
>  ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
> @@ -192,8 +185,8 @@ static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
>  		 * persistent copy in kernfs_node.
>  		 */
>  		set_inode_attr(inode, &attrs->ia_iattr);
> -		security_inode_notifysecctx(inode, attrs->ia_secdata,
> -					    attrs->ia_secdata_len);
> +		security_inode_notifysecctx(inode, attrs->ia_context.context,
> +					    attrs->ia_context.len);
>  	}
>  
>  	if (kernfs_type(kn) == KERNFS_DIR)
> @@ -350,8 +343,6 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
>  	struct kernfs_node *kn = inode->i_private;
>  	struct kernfs_iattrs *attrs;
>  	struct lsmcontext context;
> -	void *secdata;
> -	u32 secdata_len = 0;
>  	int error;
>  
>  	attrs = kernfs_iattrs(kn);
> @@ -361,18 +352,17 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
>  	error = security_inode_setsecurity(inode, suffix, value, size, flags);
>  	if (error)
>  		return error;
> -	error = security_inode_getsecctx(inode, &secdata, &secdata_len);
> +	error = security_inode_getsecctx(inode, &context);
>  	if (error)
>  		return error;
>  
>  	mutex_lock(&kernfs_mutex);
> -	error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len);
> +	kernfs_node_setsecdata(attrs, &context);
>  	mutex_unlock(&kernfs_mutex);
>  
> -	if (secdata) {
> -		lsmcontext_init(&context, secdata, secdata_len, 0);
> +	if (context.context)
>  		security_release_secctx(&context);
> -	}
> +
>  	return error;
>  }
>  
> diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
> index 0b7d197a904c..844a028d282f 100644
> --- a/fs/kernfs/kernfs-internal.h
> +++ b/fs/kernfs/kernfs-internal.h
> @@ -21,8 +21,7 @@
>  
>  struct kernfs_iattrs {
>  	struct iattr		ia_iattr;
> -	void			*ia_secdata;
> -	u32			ia_secdata_len;
> +	struct lsmcontext	ia_context;
>  
>  	struct simple_xattrs	xattrs;
>  };
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index bb3db033e144..1209083565dd 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
>  
> @@ -2420,9 +2420,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
>  	__be32 status;
>  	int err;
>  	struct nfs4_acl *acl = NULL;
> -	struct lsmcontext scaff; /* scaffolding */
> -	void *context = NULL;
> -	int contextlen;
> +	struct lsmcontext context;
>  	bool contextsupport = false;
>  	struct nfsd4_compoundres *resp = rqstp->rq_resp;
>  	u32 minorversion = resp->cstate.minorversion;
> @@ -2479,7 +2477,7 @@ 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);
> @@ -2908,8 +2906,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
>  	}
>  
>  	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;
>  	}
> @@ -2920,10 +2917,8 @@ 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 2674eb70c2d7..c16aea55be97 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -489,7 +489,7 @@ 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);
>  #else /* CONFIG_SECURITY */
>  
>  static inline int call_lsm_notifier(enum lsm_event event, void *data)
> @@ -1290,7 +1290,8 @@ 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 61cdc6bcd32e..45b9f905f5c0 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2164,9 +2164,19 @@ 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);
> +	int *display = current->security;
> +	struct security_hook_list *hp;
> +
> +	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list)
> +		if (*display == LSMBLOB_INVALID ||
> +		    *display == hp->lsmid->slot) {
> +			cp->slot = hp->lsmid->slot;
> +			return hp->hook.inode_getsecctx(inode,
> +					(void **)&cp->context, &cp->len);
> +		}
> +	return -EOPNOTSUPP;
>  }
>  EXPORT_SYMBOL(security_inode_getsecctx);
>  
> 


  parent reply	other threads:[~2019-06-27 21:37 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-26 19:22 [PATCH v4 00/23] LSM: Module stacking for AppArmor Casey Schaufler
2019-06-26 19:22 ` [PATCH v4 01/23] LSM: Infrastructure management of the superblock Casey Schaufler
2019-06-26 19:22 ` [PATCH v4 02/23] LSM: Infrastructure management of the sock security Casey Schaufler
2019-06-26 19:22 ` [PATCH v4 03/23] LSM: Infrastructure management of the key blob Casey Schaufler
2019-06-26 19:22 ` [PATCH v4 04/23] LSM: Create and manage the lsmblob data structure Casey Schaufler
2019-06-26 23:39   ` John Johansen
2019-06-27 17:43     ` Casey Schaufler
2019-06-26 19:22 ` [PATCH v4 05/23] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2019-06-26 23:07   ` Kees Cook
2019-06-26 23:45   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 06/23] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2019-06-26 23:07   ` Kees Cook
2019-06-26 23:47   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 07/23] net: Prepare UDS for secuirty module stacking Casey Schaufler
2019-06-26 23:07   ` Kees Cook
2019-06-26 23:48   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 08/23] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2019-06-26 23:07   ` Kees Cook
2019-06-26 23:50   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 09/23] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2019-06-26 23:07   ` Kees Cook
2019-06-26 23:51   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 10/23] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2019-06-26 23:08   ` Kees Cook
2019-06-26 23:53   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 11/23] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2019-06-26 23:08   ` Kees Cook
2019-06-26 23:55   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 12/23] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2019-06-26 23:08   ` Kees Cook
2019-06-26 23:56   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 13/23] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2019-06-26 23:09   ` Kees Cook
2019-06-26 23:57   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 14/23] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2019-06-26 23:09   ` Kees Cook
2019-06-26 23:58   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 15/23] LSM: Specify which LSM to display Casey Schaufler
2019-06-26 23:12   ` Kees Cook
2019-06-27 21:33   ` John Johansen
2019-06-28 14:45   ` Stephen Smalley
2019-06-28 16:15     ` Casey Schaufler
2019-06-28 18:08       ` John Johansen
     [not found]       ` <CAB9W1A1nwE7WBZqTe-GV8xNb83_B2ybV7cco++nfMjtDz9NJrg@mail.gmail.com>
2019-06-29  1:01         ` Fwd: " Stephen Smalley
2019-06-29 19:45           ` Casey Schaufler
2019-07-02  0:49           ` James Morris
2019-07-02  1:20             ` Casey Schaufler
2019-06-26 19:22 ` [PATCH v4 16/23] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2019-06-26 23:14   ` Kees Cook
2019-06-27 21:34   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 17/23] " Casey Schaufler
2019-06-26 23:15   ` Kees Cook
2019-06-27  3:53   ` Kees Cook
2019-06-27 16:29     ` Casey Schaufler
2019-06-27 17:17       ` Kees Cook
2019-06-27 17:36         ` Casey Schaufler
2019-06-27 21:34   ` John Johansen
2019-06-27 21:36     ` John Johansen
2019-06-26 19:22 ` [PATCH v4 18/23] LSM: Use lsmcontext in security_dentry_init_security Casey Schaufler
2019-06-26 23:15   ` Kees Cook
2019-06-27 21:34   ` John Johansen
2019-06-28 10:07   ` Ondrej Mosnacek
2019-06-26 19:22 ` [PATCH v4 19/23] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2019-06-26 23:16   ` Kees Cook
2019-06-27 21:36   ` John Johansen [this message]
2019-06-26 19:22 ` [PATCH v4 20/23] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2019-06-26 23:16   ` Kees Cook
2019-06-27 21:37   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 21/23] Audit: Store LSM audit information in an lsmblob Casey Schaufler
2019-06-26 23:16   ` Kees Cook
2019-06-27 21:37   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 22/23] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2019-06-26 23:18   ` Kees Cook
2019-06-27 21:38   ` John Johansen
2019-06-26 19:22 ` [PATCH v4 23/23] AppArmor: Remove the exclusive flag Casey Schaufler
2019-06-26 23:18   ` Kees Cook
2019-06-27  2:22   ` James Morris
2019-06-27  3:28     ` Kees Cook
2019-06-27  3:44     ` John Johansen
2019-06-27  3:49       ` James Morris
2019-06-27 21:38   ` John Johansen
2019-06-26 21:04 ` [PATCH v4 00/23] LSM: Module stacking for AppArmor Kees Cook
2019-06-26 21:11   ` John Johansen
2019-06-26 23:04     ` Kees Cook
2019-06-26 21:25   ` Casey Schaufler
2019-06-27  2:41 ` James Morris
2019-06-27  2:46   ` James Morris
2019-06-27  3:45     ` James Morris
2019-06-27  4:10       ` James Morris
2019-06-27 17:07         ` Kees Cook
2019-06-27 18:10           ` James Morris
2019-06-27  3:51     ` Kees Cook
2019-06-27 21:52 ` John Johansen
2019-06-27 22:33   ` Casey Schaufler
2019-06-27 23:16   ` James Morris
2019-06-27 23:44     ` John Johansen

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