On 11/13/19 10:19 AM, Casey Schaufler wrote:
> Add a new lsmcontext data structure to hold all the information
> about a "security context", including the string, its size and
> which LSM allocated the string. The allocation information is
> necessary because LSMs have different policies regarding the
> lifecycle of these strings. SELinux allocates and destroys
> them on each use, whereas Smack provides a pointer to an entry
> in a list that never goes away.
>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Reviewed-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> cc: linux-integrity@xxxxxxxxxxxxxxx
> cc: netdev@xxxxxxxxxxxxxxx
Acked-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
> ---
> drivers/android/binder.c | 10 +++++--
> fs/ceph/xattr.c | 6 +++-
> fs/nfs/nfs4proc.c | 8 +++--
> fs/nfsd/nfs4xdr.c | 7 +++--
> include/linux/security.h | 39 +++++++++++++++++++++++--
> include/net/scm.h | 5 +++-
> kernel/audit.c | 14 ++++++---
> kernel/auditsc.c | 12 ++++++--
> net/ipv4/ip_sockglue.c | 4 ++-
> net/netfilter/nf_conntrack_netlink.c | 4 ++-
> net/netfilter/nf_conntrack_standalone.c | 4 ++-
> net/netfilter/nfnetlink_queue.c | 13 ++++++---
> net/netlabel/netlabel_unlabeled.c | 19 +++++++++---
> net/netlabel/netlabel_user.c | 4 ++-
> security/security.c | 18 ++++++++----
> security/smack/smack_lsm.c | 14 ++++++---
> 16 files changed, 141 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 3a7fcdc8dbe2..49b84b6fafd9 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -2865,6 +2865,7 @@ static void binder_transaction(struct binder_proc *proc,
> int t_debug_id = atomic_inc_return(&binder_last_id);
> char *secctx = NULL;
> u32 secctx_sz = 0;
> + struct lsmcontext scaff; /* scaffolding */
>
> e = binder_transaction_log_add(&binder_transaction_log);
> e->debug_id = t_debug_id;
> @@ -3161,7 +3162,8 @@ static void binder_transaction(struct binder_proc *proc,
> t->security_ctx = 0;
> WARN_ON(1);
> }
> - security_release_secctx(secctx, secctx_sz);
> + lsmcontext_init(&scaff, secctx, secctx_sz, 0);
> + security_release_secctx(&scaff);
> secctx = NULL;
> }
> t->buffer->debug_id = t->debug_id;
> @@ -3494,8 +3496,10 @@ static void binder_transaction(struct binder_proc *proc,
> binder_alloc_free_buf(&target_proc->alloc, t->buffer);
> err_binder_alloc_buf_failed:
> err_bad_extra_size:
> - if (secctx)
> - security_release_secctx(secctx, secctx_sz);
> + if (secctx) {
> + lsmcontext_init(&scaff, secctx, secctx_sz, 0);
> + security_release_secctx(&scaff);
> + }
> err_get_secctx_failed:
> kfree(tcomplete);
> binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
> diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
> index cb18ee637cb7..ad501b5cad2c 100644
> --- a/fs/ceph/xattr.c
> +++ b/fs/ceph/xattr.c
> @@ -1271,12 +1271,16 @@ 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 lsmcontext 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
> - security_release_secctx(as_ctx->sec_ctx, as_ctx->sec_ctxlen);
> + lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0);
> + security_release_secctx(&scaff);
> #endif
> if (as_ctx->pagelist)
> ceph_pagelist_release(as_ctx->pagelist);
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index caacf5e7f5e1..74e9f4b7cc07 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -131,8 +131,12 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
> static inline void
> nfs4_label_release_security(struct nfs4_label *label)
> {
> - if (label)
> - security_release_secctx(label->label, label->len);
> + struct lsmcontext scaff; /* scaffolding */
> +
> + if (label) {
> + lsmcontext_init(&scaff, label->label, label->len, 0);
> + security_release_secctx(&scaff);
> + }
> }
> static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
> {
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 533d0fc3c96b..b17aad082bde 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -2421,6 +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;
> #endif
> @@ -2923,8 +2924,10 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
>
> out:
> #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
> - if (context)
> - security_release_secctx(context, contextlen);
> + if (context) {
> + lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
> + security_release_secctx(&scaff);
> + }
> #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
> kfree(acl);
> if (tempfh) {
> diff --git a/include/linux/security.h b/include/linux/security.h
> index f7bc7aef95cb..9bb11d9f1348 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -126,6 +126,41 @@ enum lockdown_reason {
> LOCKDOWN_CONFIDENTIALITY_MAX,
> };
>
> +/*
> + * A "security context" is the text representation of
> + * the information used by LSMs.
> + * This structure contains the string, its length, and which LSM
> + * it is useful for.
> + */
> +struct lsmcontext {
> + char *context; /* Provided by the module */
> + u32 len;
> + int slot; /* 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
> + * @slot: Which LSM provided the context
> + *
> + * Fill in the lsmcontext from the provided information.
> + * This is a scaffolding function that will be removed when
> + * lsmcontext integration is complete.
> + */
> +static inline void lsmcontext_init(struct lsmcontext *cp, char *context,
> + u32 size, int slot)
> +{
> + cp->slot = slot;
> + cp->context = context;
> +
> + if (context == NULL || size == 0)
> + cp->len = 0;
> + else
> + cp->len = strlen(context);
> +}
> +
> /*
> * Data exported by the security modules
> *
> @@ -496,7 +531,7 @@ int security_ismaclabel(const char *name);
> int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
> int security_secctx_to_secid(const char *secdata, u32 seclen,
> struct lsmblob *blob);
> -void security_release_secctx(char *secdata, u32 seclen);
> +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);
> @@ -1310,7 +1345,7 @@ static inline int security_secctx_to_secid(const char *secdata,
> return -EOPNOTSUPP;
> }
>
> -static inline void security_release_secctx(char *secdata, u32 seclen)
> +static inline void security_release_secctx(struct lsmcontext *cp)
> {
> }
>
> diff --git a/include/net/scm.h b/include/net/scm.h
> index 31ae605fcc0a..30ba801c91bd 100644
> --- a/include/net/scm.h
> +++ b/include/net/scm.h
> @@ -92,6 +92,7 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
> #ifdef CONFIG_SECURITY_NETWORK
> static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
> {
> + struct lsmcontext context;
> char *secdata;
> u32 seclen;
> int err;
> @@ -102,7 +103,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
>
> if (!err) {
> put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
> - security_release_secctx(secdata, seclen);
> + /*scaffolding*/
> + lsmcontext_init(&context, secdata, seclen, 0);
> + security_release_secctx(&context);
> }
> }
> }
> diff --git a/kernel/audit.c b/kernel/audit.c
> index ba9f78e36d1e..35970e7191b6 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -1180,6 +1180,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> struct audit_sig_info *sig_data;
> char *ctx = NULL;
> u32 len;
> + struct lsmcontext scaff; /* scaffolding */
>
> err = audit_netlink_ok(skb, msg_type);
> if (err)
> @@ -1424,15 +1425,18 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> }
> sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
> if (!sig_data) {
> - if (lsmblob_is_set(&audit_sig_lsm))
> - security_release_secctx(ctx, len);
> + if (lsmblob_is_set(&audit_sig_lsm)) {
> + lsmcontext_init(&scaff, ctx, len, 0);
> + security_release_secctx(&scaff);
> + }
> return -ENOMEM;
> }
> sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
> sig_data->pid = audit_sig_pid;
> if (lsmblob_is_set(&audit_sig_lsm)) {
> memcpy(sig_data->ctx, ctx, len);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&scaff, ctx, len, 0);
> + security_release_secctx(&scaff);
> }
> audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
> sig_data, sizeof(*sig_data) + len);
> @@ -2061,6 +2065,7 @@ int audit_log_task_context(struct audit_buffer *ab)
> unsigned len;
> int error;
> struct lsmblob blob;
> + struct lsmcontext scaff; /* scaffolding */
>
> security_task_getsecid(current, &blob);
> if (!lsmblob_is_set(&blob))
> @@ -2074,7 +2079,8 @@ int audit_log_task_context(struct audit_buffer *ab)
> }
>
> audit_log_format(ab, " subj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&scaff, ctx, len, 0);
> + security_release_secctx(&scaff);
> return 0;
>
> error_path:
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index c1e3ac8eb1ad..8790e7aafa7d 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -962,6 +962,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> struct lsmblob *blob, char *comm)
> {
> struct audit_buffer *ab;
> + struct lsmcontext lsmcxt;
> char *ctx = NULL;
> u32 len;
> int rc = 0;
> @@ -979,7 +980,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> rc = 1;
> } else {
> audit_log_format(ab, " obj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
> + security_release_secctx(&lsmcxt);
> }
> }
> audit_log_format(ab, " ocomm=");
> @@ -1192,6 +1194,7 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
>
> static void show_special(struct audit_context *context, int *call_panic)
> {
> + struct lsmcontext lsmcxt;
> struct audit_buffer *ab;
> int i;
>
> @@ -1225,7 +1228,8 @@ static void show_special(struct audit_context *context, int *call_panic)
> *call_panic = 1;
> } else {
> audit_log_format(ab, " obj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&lsmcxt, ctx, len, 0);
> + security_release_secctx(&lsmcxt);
> }
> }
> if (context->ipc.has_perm) {
> @@ -1371,6 +1375,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
> char *ctx = NULL;
> u32 len;
> struct lsmblob blob;
> + struct lsmcontext lsmcxt;
>
> lsmblob_init(&blob, n->osid);
> if (security_secid_to_secctx(&blob, &ctx, &len)) {
> @@ -1379,7 +1384,8 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
> *call_panic = 2;
> } else {
> audit_log_format(ab, " obj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
> + security_release_secctx(&lsmcxt);
> }
> }
>
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index 1ca97d0cb4a9..96d56a30ecca 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -130,6 +130,7 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
>
> static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> {
> + struct lsmcontext context;
> struct lsmblob lb;
> char *secdata;
> u32 seclen;
> @@ -144,7 +145,8 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> return;
>
> put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
> - security_release_secctx(secdata, seclen);
> + lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
> + security_release_secctx(&context);
> }
>
> static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index 0412f6744185..78791e015d8b 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -332,6 +332,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
> int len, ret;
> char *secctx;
> struct lsmblob blob;
> + struct lsmcontext context;
>
> lsmblob_init(&blob, ct->secmark);
> ret = security_secid_to_secctx(&blob, &secctx, &len);
> @@ -349,7 +350,8 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
>
> ret = 0;
> nla_put_failure:
> - security_release_secctx(secctx, len);
> + lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
> + security_release_secctx(&context);
> return ret;
> }
> #else
> diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
> index 183a85412155..8601fcb99f7a 100644
> --- a/net/netfilter/nf_conntrack_standalone.c
> +++ b/net/netfilter/nf_conntrack_standalone.c
> @@ -176,6 +176,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
> u32 len;
> char *secctx;
> struct lsmblob blob;
> + struct lsmcontext context;
>
> lsmblob_init(&blob, ct->secmark);
> ret = security_secid_to_secctx(&blob, &secctx, &len);
> @@ -184,7 +185,8 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
>
> seq_printf(s, "secctx=%s ", secctx);
>
> - security_release_secctx(secctx, len);
> + lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
> + security_release_secctx(&context);
> }
> #else
> static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
> index bfa7f12fde99..cc3ef03ee198 100644
> --- a/net/netfilter/nfnetlink_queue.c
> +++ b/net/netfilter/nfnetlink_queue.c
> @@ -395,6 +395,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
> enum ip_conntrack_info uninitialized_var(ctinfo);
> struct nfnl_ct_hook *nfnl_ct;
> bool csum_verify;
> + struct lsmcontext scaff; /* scaffolding */
> char *secdata = NULL;
> u32 seclen = 0;
>
> @@ -625,8 +626,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
> }
>
> nlh->nlmsg_len = skb->len;
> - if (seclen)
> - security_release_secctx(secdata, seclen);
> + if (seclen) {
> + lsmcontext_init(&scaff, secdata, seclen, 0);
> + security_release_secctx(&scaff);
> + }
> return skb;
>
> nla_put_failure:
> @@ -634,8 +637,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
> kfree_skb(skb);
> net_err_ratelimited("nf_queue: error creating packet message\n");
> nlmsg_failure:
> - if (seclen)
> - security_release_secctx(secdata, seclen);
> + if (seclen) {
> + lsmcontext_init(&scaff, secdata, seclen, 0);
> + security_release_secctx(&scaff);
> + }
> return NULL;
> }
>
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index e279b81d9545..288c005b44c7 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -373,6 +373,7 @@ int netlbl_unlhsh_add(struct net *net,
> struct net_device *dev;
> struct netlbl_unlhsh_iface *iface;
> struct audit_buffer *audit_buf = NULL;
> + struct lsmcontext context;
> char *secctx = NULL;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -443,7 +444,9 @@ int netlbl_unlhsh_add(struct net *net,
> &secctx,
> &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + /* scaffolding */
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
> audit_log_end(audit_buf);
> @@ -474,6 +477,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> struct netlbl_unlhsh_addr4 *entry;
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> + struct lsmcontext context;
> char *secctx;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -502,7 +506,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> security_secid_to_secctx(&blob,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + /* scaffolding */
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
> audit_log_end(audit_buf);
> @@ -539,6 +545,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> struct netlbl_unlhsh_addr6 *entry;
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> + struct lsmcontext context;
> char *secctx;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -566,7 +573,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> security_secid_to_secctx(&blob,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
> audit_log_end(audit_buf);
> @@ -1080,6 +1088,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> int ret_val = -ENOMEM;
> struct netlbl_unlhsh_walk_arg *cb_arg = arg;
> struct net_device *dev;
> + struct lsmcontext context;
> void *data;
> u32 secid;
> char *secctx;
> @@ -1147,7 +1156,9 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> NLBL_UNLABEL_A_SECCTX,
> secctx_len,
> secctx);
> - security_release_secctx(secctx, secctx_len);
> + /* scaffolding */
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> if (ret_val != 0)
> goto list_cb_failure;
>
> diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
> index 893301ae0131..ef139d8ae7cd 100644
> --- a/net/netlabel/netlabel_user.c
> +++ b/net/netlabel/netlabel_user.c
> @@ -84,6 +84,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> struct netlbl_audit *audit_info)
> {
> struct audit_buffer *audit_buf;
> + struct lsmcontext context;
> char *secctx;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -103,7 +104,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> if (audit_info->secid != 0 &&
> security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " subj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
> + security_release_secctx(&context);
> }
>
> return audit_buf;
> diff --git a/security/security.c b/security/security.c
> index c2874f6587d2..c05ef9d0c8ed 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2144,17 +2144,23 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
> }
> EXPORT_SYMBOL(security_secctx_to_secid);
>
> -void security_release_secctx(char *secdata, u32 seclen)
> +void security_release_secctx(struct lsmcontext *cp)
> {
> struct security_hook_list *hp;
> - int *display = current->security;
> + bool found = false;
>
> hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
> - if (display == NULL || *display == LSMBLOB_INVALID ||
> - *display == hp->lsmid->slot) {
> - hp->hook.release_secctx(secdata, seclen);
> - return;
> + if (cp->slot == hp->lsmid->slot) {
> + hp->hook.release_secctx(cp->context, cp->len);
> + found = true;
> + break;
> }
> +
> + memset(cp, 0, sizeof(*cp));
> +
> + if (!found)
> + pr_warn("%s context \"%s\" from slot %d not released\n",
> + __func__, cp->context, cp->slot);
> }
> EXPORT_SYMBOL(security_release_secctx);
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index aac8cb0de733..4e464e5e942e 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -4483,11 +4483,16 @@ static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
> return 0;
> }
>
> -/*
> - * There used to be a smack_release_secctx hook
> - * that did nothing back when hooks were in a vector.
> - * Now that there's a list such a hook adds cost.
> +/**
> + * smack_release_secctx - do everything necessary to free a context
> + * @secdata: Unused
> + * @seclen: Unused
> + *
> + * Do nothing but hold a slot in the hooks list.
> */
> +static void smack_release_secctx(char *secdata, u32 seclen)
> +{
> +}
>
> static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
> {
> @@ -4730,6 +4735,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
> LSM_HOOK_INIT(ismaclabel, smack_ismaclabel),
> LSM_HOOK_INIT(secid_to_secctx, smack_secid_to_secctx),
> LSM_HOOK_INIT(secctx_to_secid, smack_secctx_to_secid),
> + LSM_HOOK_INIT(release_secctx, smack_release_secctx),
> LSM_HOOK_INIT(inode_notifysecctx, smack_inode_notifysecctx),
> LSM_HOOK_INIT(inode_setsecctx, smack_inode_setsecctx),
> LSM_HOOK_INIT(inode_getsecctx, smack_inode_getsecctx),
>
