[PATCH v37 16/33] LSM: Use lsmcontext in security_secid_to_secctx

From: Casey Schaufler
Date: Mon Jun 27 2022 - 21:08:04 EST

Replace the (secctx,seclen) pointer pair with a single
lsmcontext 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.

security_secid_to_secctx() will now return the length value
if the passed lsmcontext pointer is NULL.

Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-audit@xxxxxxxxxx
Cc: netfilter-devel@xxxxxxxxxxxxxxx
---
drivers/android/binder.c | 26 ++++++---------
include/linux/security.h | 4 +--
include/net/scm.h | 9 ++----
kernel/audit.c | 42 +++++++++++--------------
kernel/auditsc.c | 31 +++++++-----------
net/ipv4/ip_sockglue.c | 8 ++---
net/netfilter/nf_conntrack_netlink.c | 18 ++++-------
net/netfilter/nf_conntrack_standalone.c | 7 ++---
net/netfilter/nfnetlink_queue.c | 5 ++-
net/netlabel/netlabel_unlabeled.c | 40 +++++++----------------
net/netlabel/netlabel_user.c | 7 ++---
security/security.c | 29 +++++++++++++++--
12 files changed, 99 insertions(+), 127 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 9c1ed7fbda87..8ae1a624cd37 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2781,9 +2781,7 @@ static void binder_transaction(struct binder_proc *proc,
binder_size_t last_fixup_min_off = 0;
struct binder_context *context = proc->context;
int t_debug_id = atomic_inc_return(&binder_last_id);
- char *secctx = NULL;
- u32 secctx_sz = 0;
- struct lsmcontext scaff; /* scaffolding */
+ struct lsmcontext lsmctx = { };
struct list_head sgc_head;
struct list_head pf_head;
const void __user *user_buffer = (const void __user *)
@@ -3059,7 +3057,7 @@ static void binder_transaction(struct binder_proc *proc,
size_t added_size;

security_cred_getsecid(proc->cred, &blob);
- ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
+ ret = security_secid_to_secctx(&blob, &lsmctx);
if (ret) {
binder_txn_error("%d:%d failed to get security context\n",
thread->pid, proc->pid);
@@ -3068,7 +3066,7 @@ static void binder_transaction(struct binder_proc *proc,
return_error_line = __LINE__;
goto err_get_secctx_failed;
}
- added_size = ALIGN(secctx_sz, sizeof(u64));
+ added_size = ALIGN(lsmctx.len, sizeof(u64));
extra_buffers_size += added_size;
if (extra_buffers_size < added_size) {
binder_txn_error("%d:%d integer overflow of extra_buffers_size\n",
@@ -3102,24 +3100,22 @@ static void binder_transaction(struct binder_proc *proc,
t->buffer = NULL;
goto err_binder_alloc_buf_failed;
}
- if (secctx) {
+ if (lsmctx.context) {
int err;
size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) +
ALIGN(tr->offsets_size, sizeof(void *)) +
ALIGN(extra_buffers_size, sizeof(void *)) -
- ALIGN(secctx_sz, sizeof(u64));
+ ALIGN(lsmctx.len, sizeof(u64));

t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
err = binder_alloc_copy_to_buffer(&target_proc->alloc,
t->buffer, buf_offset,
- secctx, secctx_sz);
+ lsmctx.context, lsmctx.len);
if (err) {
t->security_ctx = 0;
WARN_ON(1);
}
- lsmcontext_init(&scaff, secctx, secctx_sz, 0);
- security_release_secctx(&scaff);
- secctx = NULL;
+ security_release_secctx(&lsmctx);
}
t->buffer->debug_id = t->debug_id;
t->buffer->transaction = t;
@@ -3163,7 +3159,7 @@ static void binder_transaction(struct binder_proc *proc,
off_end_offset = off_start_offset + tr->offsets_size;
sg_buf_offset = ALIGN(off_end_offset, sizeof(void *));
sg_buf_end_offset = sg_buf_offset + extra_buffers_size -
- ALIGN(secctx_sz, sizeof(u64));
+ ALIGN(lsmctx.len, sizeof(u64));
off_min = 0;
for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
buffer_offset += sizeof(binder_size_t)) {
@@ -3534,10 +3530,8 @@ 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) {
- lsmcontext_init(&scaff, secctx, secctx_sz, 0);
- security_release_secctx(&scaff);
- }
+ if (lsmctx.context)
+ security_release_secctx(&lsmctx);
err_get_secctx_failed:
kfree(tcomplete);
binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
diff --git a/include/linux/security.h b/include/linux/security.h
index a20fc156c697..5afd0148a1a5 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -617,7 +617,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
size_t size);
int security_netlink_send(struct sock *sk, struct sk_buff *skb);
int security_ismaclabel(const char *name);
-int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
int security_secctx_to_secid(const char *secdata, u32 seclen,
struct lsmblob *blob);
void security_release_secctx(struct lsmcontext *cp);
@@ -1472,7 +1472,7 @@ static inline int security_ismaclabel(const char *name)
}

static inline int security_secid_to_secctx(struct lsmblob *blob,
- char **secdata, u32 *seclen)
+ struct lsmcontext *cp)
{
return -EOPNOTSUPP;
}
diff --git a/include/net/scm.h b/include/net/scm.h
index f273c4d777ec..b77a52f93389 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -94,8 +94,6 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
{
struct lsmcontext context;
struct lsmblob lb;
- char *secdata;
- u32 seclen;
int err;

if (test_bit(SOCK_PASSSEC, &sock->flags)) {
@@ -103,12 +101,11 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
* and the infrastructure will know which it is.
*/
lsmblob_init(&lb, scm->secid);
- err = security_secid_to_secctx(&lb, &secdata, &seclen);
+ err = security_secid_to_secctx(&lb, &context);

if (!err) {
- put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
- /*scaffolding*/
- lsmcontext_init(&context, secdata, seclen, 0);
+ put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len,
+ context.context);
security_release_secctx(&context);
}
}
diff --git a/kernel/audit.c b/kernel/audit.c
index 23c8f8cbe8a6..6500d97ce9ad 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1212,9 +1212,6 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
struct audit_buffer *ab;
u16 msg_type = nlh->nlmsg_type;
struct audit_sig_info *sig_data;
- char *ctx = NULL;
- u32 len;
- struct lsmcontext scaff; /* scaffolding */

err = audit_netlink_ok(skb, msg_type);
if (err)
@@ -1462,33 +1459,33 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
kfree(new);
break;
}
- case AUDIT_SIGNAL_INFO:
- len = 0;
+ case AUDIT_SIGNAL_INFO: {
+ struct lsmcontext context = { };
+
if (lsmblob_is_set(&audit_sig_lsm)) {
- err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
- &len);
+ err = security_secid_to_secctx(&audit_sig_lsm,
+ &context);
if (err)
return err;
}
- sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
+ sig_data = kmalloc(struct_size(sig_data, ctx, context.len),
+ GFP_KERNEL);
if (!sig_data) {
- if (lsmblob_is_set(&audit_sig_lsm)) {
- lsmcontext_init(&scaff, ctx, len, 0);
- security_release_secctx(&scaff);
- }
+ if (lsmblob_is_set(&audit_sig_lsm))
+ security_release_secctx(&context);
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);
- lsmcontext_init(&scaff, ctx, len, 0);
- security_release_secctx(&scaff);
+ memcpy(sig_data->ctx, context.context, context.len);
+ security_release_secctx(&context);
}
- audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
- sig_data, struct_size(sig_data, ctx, len));
+ audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, sig_data,
+ struct_size(sig_data, ctx, context.len));
kfree(sig_data);
break;
+ }
case AUDIT_TTY_GET: {
struct audit_tty_status s;
unsigned int t;
@@ -2171,17 +2168,15 @@ void audit_log_key(struct audit_buffer *ab, char *key)

int audit_log_task_context(struct audit_buffer *ab)
{
- char *ctx = NULL;
- unsigned len;
int error;
struct lsmblob blob;
- struct lsmcontext scaff; /* scaffolding */
+ struct lsmcontext context;

security_current_getsecid_subj(&blob);
if (!lsmblob_is_set(&blob))
return 0;

- error = security_secid_to_secctx(&blob, &ctx, &len);
+ error = security_secid_to_secctx(&blob, &context);

if (error) {
if (error != -EINVAL)
@@ -2189,9 +2184,8 @@ int audit_log_task_context(struct audit_buffer *ab)
return 0;
}

- audit_log_format(ab, " subj=%s", ctx);
- lsmcontext_init(&scaff, ctx, len, 0);
- security_release_secctx(&scaff);
+ audit_log_format(ab, " subj=%s", context.context);
+ security_release_secctx(&context);
return 0;

error_path:
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 9ed58db58965..25a6c2a5b4b3 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1121,9 +1121,7 @@ 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;
+ struct lsmcontext lsmctx;
int rc = 0;

ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1134,13 +1132,12 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
from_kuid(&init_user_ns, auid),
from_kuid(&init_user_ns, uid), sessionid);
if (lsmblob_is_set(blob)) {
- if (security_secid_to_secctx(blob, &ctx, &len)) {
+ if (security_secid_to_secctx(blob, &lsmctx)) {
audit_log_format(ab, " obj=(none)");
rc = 1;
} else {
- audit_log_format(ab, " obj=%s", ctx);
- lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
- security_release_secctx(&lsmcxt);
+ audit_log_format(ab, " obj=%s", lsmctx.context);
+ security_release_secctx(&lsmctx);
}
}
audit_log_format(ab, " ocomm=");
@@ -1400,7 +1397,6 @@ static void audit_log_time(struct audit_context *context, struct audit_buffer **

static void show_special(struct audit_context *context, int *call_panic)
{
- struct lsmcontext lsmcxt;
struct audit_buffer *ab;
int i;

@@ -1425,17 +1421,15 @@ static void show_special(struct audit_context *context, int *call_panic)
from_kgid(&init_user_ns, context->ipc.gid),
context->ipc.mode);
if (osid) {
- char *ctx = NULL;
- u32 len;
+ struct lsmcontext lsmcxt;
struct lsmblob blob;

lsmblob_init(&blob, osid);
- if (security_secid_to_secctx(&blob, &ctx, &len)) {
+ if (security_secid_to_secctx(&blob, &lsmcxt)) {
audit_log_format(ab, " osid=%u", osid);
*call_panic = 1;
} else {
- audit_log_format(ab, " obj=%s", ctx);
- lsmcontext_init(&lsmcxt, ctx, len, 0);
+ audit_log_format(ab, " obj=%s", lsmcxt.context);
security_release_secctx(&lsmcxt);
}
}
@@ -1595,20 +1589,17 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
MAJOR(n->rdev),
MINOR(n->rdev));
if (n->osid != 0) {
- char *ctx = NULL;
- u32 len;
struct lsmblob blob;
- struct lsmcontext lsmcxt;
+ struct lsmcontext lsmctx;

lsmblob_init(&blob, n->osid);
- if (security_secid_to_secctx(&blob, &ctx, &len)) {
+ if (security_secid_to_secctx(&blob, &lsmctx)) {
audit_log_format(ab, " osid=%u", n->osid);
if (call_panic)
*call_panic = 2;
} else {
- audit_log_format(ab, " obj=%s", ctx);
- lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
- security_release_secctx(&lsmcxt);
+ audit_log_format(ab, " obj=%s", lsmctx.context);
+ security_release_secctx(&lsmctx);
}
}

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 70ca4510ea35..ad5be7707bca 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -132,8 +132,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
{
struct lsmcontext context;
struct lsmblob lb;
- char *secdata;
- u32 seclen, secid;
+ u32 secid;
int err;

err = security_socket_getpeersec_dgram(NULL, skb, &secid);
@@ -141,12 +140,11 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
return;

lsmblob_init(&lb, secid);
- err = security_secid_to_secctx(&lb, &secdata, &seclen);
+ err = security_secid_to_secctx(&lb, &context);
if (err)
return;

- put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
- lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
+ put_cmsg(msg, SOL_IP, SCM_SECURITY, context.len, context.context);
security_release_secctx(&context);
}

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index da36301e2185..8bd6ce5f9e93 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -345,8 +345,7 @@ static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
{
struct nlattr *nest_secctx;
- int len, ret;
- char *secctx;
+ int ret;
struct lsmblob blob;
struct lsmcontext context;

@@ -354,7 +353,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
* security_secid_to_secctx() will know which security module
* to use to create the secctx. */
lsmblob_init(&blob, ct->secmark);
- ret = security_secid_to_secctx(&blob, &secctx, &len);
+ ret = security_secid_to_secctx(&blob, &context);
if (ret)
return 0;

@@ -363,13 +362,12 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
if (!nest_secctx)
goto nla_put_failure;

- if (nla_put_string(skb, CTA_SECCTX_NAME, secctx))
+ if (nla_put_string(skb, CTA_SECCTX_NAME, context.context))
goto nla_put_failure;
nla_nest_end(skb, nest_secctx);

ret = 0;
nla_put_failure:
- lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
security_release_secctx(&context);
return ret;
}
@@ -662,15 +660,11 @@ static inline size_t ctnetlink_acct_size(const struct nf_conn *ct)
static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
{
#ifdef CONFIG_NF_CONNTRACK_SECMARK
- int len, ret;
+ int len;
struct lsmblob blob;

- /* lsmblob_init() puts ct->secmark into all of the secids in blob.
- * security_secid_to_secctx() will know which security module
- * to use to create the secctx. */
- lsmblob_init(&blob, ct->secmark);
- ret = security_secid_to_secctx(&blob, NULL, &len);
- if (ret)
+ len = security_secid_to_secctx(&blob, NULL);
+ if (len <= 0)
return 0;

return nla_total_size(0) /* CTA_SECCTX */
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 644dec6a8ef5..5003acf79794 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -176,19 +176,16 @@ static void ct_seq_stop(struct seq_file *s, void *v)
static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
{
int ret;
- u32 len;
- char *secctx;
struct lsmblob blob;
struct lsmcontext context;

lsmblob_init(&blob, ct->secmark);
- ret = security_secid_to_secctx(&blob, &secctx, &len);
+ ret = security_secid_to_secctx(&blob, &context);
if (ret)
return;

- seq_printf(s, "secctx=%s ", secctx);
+ seq_printf(s, "secctx=%s ", context.context);

- lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
security_release_secctx(&context);
}
#else
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index f69d5e997da2..35c3cde6bacd 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -306,6 +306,7 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
u32 seclen = 0;
#if IS_ENABLED(CONFIG_NETWORK_SECMARK)
struct lsmblob blob;
+ struct lsmcontext context = { };

if (!skb || !sk_fullsock(skb->sk))
return 0;
@@ -317,10 +318,12 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
* blob. security_secid_to_secctx() will know which security
* module to use to create the secctx. */
lsmblob_init(&blob, skb->secmark);
- security_secid_to_secctx(&blob, secdata, &seclen);
+ security_secid_to_secctx(&blob, &context);
+ *secdata = context.context;
}

read_unlock_bh(&skb->sk->sk_callback_lock);
+ seclen = context.len;
#endif
return seclen;
}
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index b3e3d920034d..12e5d508bd08 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -375,8 +375,6 @@ int netlbl_unlhsh_add(struct net *net,
struct netlbl_unlhsh_iface *iface;
struct audit_buffer *audit_buf = NULL;
struct lsmcontext context;
- char *secctx = NULL;
- u32 secctx_len;
struct lsmblob blob;

if (addr_len != sizeof(struct in_addr) &&
@@ -444,12 +442,9 @@ int netlbl_unlhsh_add(struct net *net,
* security_secid_to_secctx() will know which security module
* to use to create the secctx. */
lsmblob_init(&blob, secid);
- if (security_secid_to_secctx(&blob,
- &secctx,
- &secctx_len) == 0) {
- audit_log_format(audit_buf, " sec_obj=%s", secctx);
- /* scaffolding */
- lsmcontext_init(&context, secctx, secctx_len, 0);
+ if (security_secid_to_secctx(&blob, &context) == 0) {
+ audit_log_format(audit_buf, " sec_obj=%s",
+ context.context);
security_release_secctx(&context);
}
audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
@@ -482,8 +477,6 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
struct audit_buffer *audit_buf;
struct net_device *dev;
struct lsmcontext context;
- char *secctx;
- u32 secctx_len;
struct lsmblob blob;

spin_lock(&netlbl_unlhsh_lock);
@@ -509,11 +502,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
if (entry != NULL)
lsmblob_init(&blob, entry->secid);
if (entry != NULL &&
- security_secid_to_secctx(&blob,
- &secctx, &secctx_len) == 0) {
- audit_log_format(audit_buf, " sec_obj=%s", secctx);
- /* scaffolding */
- lsmcontext_init(&context, secctx, secctx_len, 0);
+ security_secid_to_secctx(&blob, &context) == 0) {
+ audit_log_format(audit_buf, " sec_obj=%s",
+ context.context);
security_release_secctx(&context);
}
audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
@@ -552,8 +543,6 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
struct audit_buffer *audit_buf;
struct net_device *dev;
struct lsmcontext context;
- char *secctx;
- u32 secctx_len;
struct lsmblob blob;

spin_lock(&netlbl_unlhsh_lock);
@@ -578,10 +567,9 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
if (entry != NULL)
lsmblob_init(&blob, entry->secid);
if (entry != NULL &&
- security_secid_to_secctx(&blob,
- &secctx, &secctx_len) == 0) {
- audit_log_format(audit_buf, " sec_obj=%s", secctx);
- lsmcontext_init(&context, secctx, secctx_len, 0);
+ security_secid_to_secctx(&blob, &context) == 0) {
+ audit_log_format(audit_buf, " sec_obj=%s",
+ context.context);
security_release_secctx(&context);
}
audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
@@ -1104,8 +1092,6 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
struct lsmcontext context;
void *data;
u32 secid;
- char *secctx;
- u32 secctx_len;
struct lsmblob blob;

data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
@@ -1165,15 +1151,13 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
* security_secid_to_secctx() will know which security module
* to use to create the secctx. */
lsmblob_init(&blob, secid);
- ret_val = security_secid_to_secctx(&blob, &secctx, &secctx_len);
+ ret_val = security_secid_to_secctx(&blob, &context);
if (ret_val != 0)
goto list_cb_failure;
ret_val = nla_put(cb_arg->skb,
NLBL_UNLABEL_A_SECCTX,
- secctx_len,
- secctx);
- /* scaffolding */
- lsmcontext_init(&context, secctx, secctx_len, 0);
+ context.len,
+ context.context);
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 ef139d8ae7cd..951ba0639d20 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -85,8 +85,6 @@ struct audit_buffer *netlbl_audit_start_common(int type,
{
struct audit_buffer *audit_buf;
struct lsmcontext context;
- char *secctx;
- u32 secctx_len;
struct lsmblob blob;

if (audit_enabled == AUDIT_OFF)
@@ -102,9 +100,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,

lsmblob_init(&blob, audit_info->secid);
if (audit_info->secid != 0 &&
- security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
- audit_log_format(audit_buf, " subj=%s", secctx);
- lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
+ security_secid_to_secctx(&blob, &context) == 0) {
+ audit_log_format(audit_buf, " subj=%s", context.context);
security_release_secctx(&context);
}

diff --git a/security/security.c b/security/security.c
index e434f085afab..b52c7c55a092 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2337,18 +2337,41 @@ int security_ismaclabel(const char *name)
}
EXPORT_SYMBOL(security_ismaclabel);

-int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
+/**
+ * security_secid_to_secctx - convert secid to secctx
+ * @blob: set of secids
+ * @cp: lsm context into which result is put
+ *
+ * Translate secid information into a secctx string.
+ * Return a negative value on error.
+ * If cp is NULL return the length of the string.
+ * Otherwise, return 0.
+ */
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
{
struct security_hook_list *hp;
int ilsm = lsm_task_ilsm(current);

+ if (cp)
+ memset(cp, 0, sizeof(*cp));
+
hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
continue;
- if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+ if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot) {
+ if (!cp) {
+ int len;
+ int rc;
+ rc = hp->hook.secid_to_secctx(
+ blob->secid[hp->lsmid->slot],
+ NULL, &len);
+ return rc ? rc : len;
+ }
+ cp->slot = hp->lsmid->slot;
return hp->hook.secid_to_secctx(
blob->secid[hp->lsmid->slot],
- secdata, seclen);
+ &cp->context, &cp->len);
+ }
}

return LSM_RET_DEFAULT(secid_to_secctx);
--
2.36.1