[PATCH v2 09/25] LSM: Use lsmblob in security_secid_to_secctx
Kees Cook
keescook at chromium.org
Wed Jun 19 05:03:06 UTC 2019
On Tue, Jun 18, 2019 at 04:05:35PM -0700, Casey Schaufler wrote:
> Change security_secid_to_secctx() to take a lsmblob as input
> instead of a u32 secid. It will then call the LSM hooks
> using the lsmblob element allocated for that module. The
> callers have been updated as well. This allows for the
> possibility that more than one module may called upon
> to translate a secid to a string, as can occur in the
> audit code.
Cool. The progression of scaffolding here is pretty clear to me.
-Kees
>
> Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
> ---
> drivers/android/binder.c | 4 +++-
> include/linux/security.h | 5 +++--
> include/net/scm.h | 4 +---
> kernel/audit.c | 9 +++++++--
> kernel/auditsc.c | 13 +++++++++----
> net/ipv4/ip_sockglue.c | 3 +--
> net/netfilter/nf_conntrack_netlink.c | 8 ++++++--
> net/netfilter/nf_conntrack_standalone.c | 4 +++-
> net/netfilter/nfnetlink_queue.c | 8 ++++++--
> net/netlabel/netlabel_unlabeled.c | 18 ++++++++++++++----
> net/netlabel/netlabel_user.c | 6 +++---
> security/security.c | 14 +++++++++++---
> 12 files changed, 67 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 8685882da64c..a3204fbc1f28 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -3120,9 +3120,11 @@ static void binder_transaction(struct binder_proc *proc,
>
> if (target_node && target_node->txn_security_ctx) {
> u32 secid;
> + struct lsmblob le;
>
> security_task_getsecid(proc->tsk, &secid);
> - ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
> + lsmblob_init(&le, secid);
> + ret = security_secid_to_secctx(&le, &secctx, &secctx_sz);
> if (ret) {
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> diff --git a/include/linux/security.h b/include/linux/security.h
> index dcaaa63b79b3..c9ed83e57a97 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -442,7 +442,7 @@ 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(u32 secid, char **secdata, u32 *seclen);
> +int security_secid_to_secctx(struct lsmblob *l, char **secdata, u32 *seclen);
> int security_secctx_to_secid(const char *secdata, u32 seclen,
> struct lsmblob *l);
> void security_release_secctx(char *secdata, u32 seclen);
> @@ -1220,7 +1220,8 @@ static inline int security_ismaclabel(const char *name)
> return 0;
> }
>
> -static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
> +static inline int security_secid_to_secctx(struct lsmblob *l,
> + char **secdata, u32 *seclen)
> {
> return -EOPNOTSUPP;
> }
> diff --git a/include/net/scm.h b/include/net/scm.h
> index c87a17101c86..bcb0f8560cdf 100644
> --- a/include/net/scm.h
> +++ b/include/net/scm.h
> @@ -97,9 +97,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
> int err;
>
> if (test_bit(SOCK_PASSSEC, &sock->flags)) {
> - /* Scaffolding - it has to be element 1 for now */
> - err = security_secid_to_secctx(scm->lsmblob.secid[1],
> - &secdata, &seclen);
> + err = security_secid_to_secctx(&scm->lsmblob, &secdata, &seclen);
>
> if (!err) {
> put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
> diff --git a/kernel/audit.c b/kernel/audit.c
> index c89ea48c70a6..5efd78ced915 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -1430,7 +1430,10 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> case AUDIT_SIGNAL_INFO:
> len = 0;
> if (audit_sig_sid) {
> - err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
> + struct lsmblob le;
> +
> + lsmblob_init(&le, audit_sig_sid);
> + err = security_secid_to_secctx(&le, &ctx, &len);
> if (err)
> return err;
> }
> @@ -2073,12 +2076,14 @@ int audit_log_task_context(struct audit_buffer *ab)
> unsigned len;
> int error;
> u32 sid;
> + struct lsmblob le;
>
> security_task_getsecid(current, &sid);
> if (!sid)
> return 0;
>
> - error = security_secid_to_secctx(sid, &ctx, &len);
> + lsmblob_init(&le, sid);
> + error = security_secid_to_secctx(&le, &ctx, &len);
> if (error) {
> if (error != -EINVAL)
> goto error_path;
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 93c74205ef40..67d3f71a095a 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -946,6 +946,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> char *ctx = NULL;
> u32 len;
> int rc = 0;
> + struct lsmblob le;
>
> ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
> if (!ab)
> @@ -955,7 +956,8 @@ 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 (sid) {
> - if (security_secid_to_secctx(sid, &ctx, &len)) {
> + lsmblob_init(&le, sid);
> + if (security_secid_to_secctx(&le, &ctx, &len)) {
> audit_log_format(ab, " obj=(none)");
> rc = 1;
> } else {
> @@ -1197,7 +1199,9 @@ static void show_special(struct audit_context *context, int *call_panic)
> if (osid) {
> char *ctx = NULL;
> u32 len;
> - if (security_secid_to_secctx(osid, &ctx, &len)) {
> + struct lsmblob le;
> + lsmblob_init(&le, osid);
> + if (security_secid_to_secctx(&le, &ctx, &len)) {
> audit_log_format(ab, " osid=%u", osid);
> *call_panic = 1;
> } else {
> @@ -1348,9 +1352,10 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
> if (n->osid != 0) {
> char *ctx = NULL;
> u32 len;
> + struct lsmblob le;
>
> - if (security_secid_to_secctx(
> - n->osid, &ctx, &len)) {
> + lsmblob_init(&le, n->osid);
> + if (security_secid_to_secctx(&le, &ctx, &len)) {
> audit_log_format(ab, " osid=%u", n->osid);
> if (call_panic)
> *call_panic = 2;
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index fbe2147ee595..e05f4ef68bd8 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -139,8 +139,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> if (err)
> return;
>
> - /* Scaffolding - it has to be element 1 */
> - err = security_secid_to_secctx(lb.secid[1], &secdata, &seclen);
> + err = security_secid_to_secctx(&lb, &secdata, &seclen);
> if (err)
> return;
>
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index 66c596d287a5..6098b586da07 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -330,8 +330,10 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
> struct nlattr *nest_secctx;
> int len, ret;
> char *secctx;
> + struct lsmblob le;
>
> - ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
> + lsmblob_init(&le, ct->secmark);
> + ret = security_secid_to_secctx(&le, &secctx, &len);
> if (ret)
> return 0;
>
> @@ -615,8 +617,10 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
> {
> #ifdef CONFIG_NF_CONNTRACK_SECMARK
> int len, ret;
> + struct lsmblob le;
>
> - ret = security_secid_to_secctx(ct->secmark, NULL, &len);
> + lsmblob_init(&le, ct->secmark);
> + ret = security_secid_to_secctx(&le, NULL, &len);
> if (ret)
> return 0;
>
> diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
> index c2ae14c720b4..6e6fb1f9f6ba 100644
> --- a/net/netfilter/nf_conntrack_standalone.c
> +++ b/net/netfilter/nf_conntrack_standalone.c
> @@ -175,8 +175,10 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
> int ret;
> u32 len;
> char *secctx;
> + struct lsmblob le;
>
> - ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
> + lsmblob_init(&le, ct->secmark);
> + ret = security_secid_to_secctx(&le, &secctx, &len);
> if (ret)
> return;
>
> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
> index 0dcc3592d053..105018d19318 100644
> --- a/net/netfilter/nfnetlink_queue.c
> +++ b/net/netfilter/nfnetlink_queue.c
> @@ -309,13 +309,17 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
> {
> u32 seclen = 0;
> #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
> + struct lsmblob le;
> +
> if (!skb || !sk_fullsock(skb->sk))
> return 0;
>
> read_lock_bh(&skb->sk->sk_callback_lock);
>
> - if (skb->secmark)
> - security_secid_to_secctx(skb->secmark, secdata, &seclen);
> + if (skb->secmark) {
> + lsmblob_init(&le, skb->secmark);
> + security_secid_to_secctx(&le, secdata, &seclen);
> + }
>
> read_unlock_bh(&skb->sk->sk_callback_lock);
> #endif
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index 30873e671d05..46ac9721e261 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -389,6 +389,7 @@ int netlbl_unlhsh_add(struct net *net,
> struct audit_buffer *audit_buf = NULL;
> char *secctx = NULL;
> u32 secctx_len;
> + struct lsmblob le;
>
> if (addr_len != sizeof(struct in_addr) &&
> addr_len != sizeof(struct in6_addr))
> @@ -451,7 +452,8 @@ int netlbl_unlhsh_add(struct net *net,
> unlhsh_add_return:
> rcu_read_unlock();
> if (audit_buf != NULL) {
> - if (security_secid_to_secctx(secid,
> + lsmblob_init(&le, secid);
> + if (security_secid_to_secctx(&le,
> &secctx,
> &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> @@ -488,6 +490,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> struct net_device *dev;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob le;
>
> spin_lock(&netlbl_unlhsh_lock);
> list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
> @@ -507,8 +510,10 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> addr->s_addr, mask->s_addr);
> if (dev != NULL)
> dev_put(dev);
> + if (entry != NULL)
> + lsmblob_init(&le, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(entry->secid,
> + security_secid_to_secctx(&le,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> security_release_secctx(secctx, secctx_len);
> @@ -550,6 +555,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> struct net_device *dev;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob le;
>
> spin_lock(&netlbl_unlhsh_lock);
> list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
> @@ -568,8 +574,10 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> addr, mask);
> if (dev != NULL)
> dev_put(dev);
> + if (entry != NULL)
> + lsmblob_init(&le, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(entry->secid,
> + security_secid_to_secctx(&le,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> security_release_secctx(secctx, secctx_len);
> @@ -1090,6 +1098,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> u32 secid;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob le;
>
> data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
> cb_arg->seq, &netlbl_unlabel_gnl_family,
> @@ -1144,7 +1153,8 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> secid = addr6->secid;
> }
>
> - ret_val = security_secid_to_secctx(secid, &secctx, &secctx_len);
> + lsmblob_init(&le, secid);
> + ret_val = security_secid_to_secctx(&le, &secctx, &secctx_len);
> if (ret_val != 0)
> goto list_cb_failure;
> ret_val = nla_put(cb_arg->skb,
> diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
> index 4676f5bb16ae..4145adf55a22 100644
> --- a/net/netlabel/netlabel_user.c
> +++ b/net/netlabel/netlabel_user.c
> @@ -100,6 +100,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> struct audit_buffer *audit_buf;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob le;
>
> if (audit_enabled == AUDIT_OFF)
> return NULL;
> @@ -112,10 +113,9 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> from_kuid(&init_user_ns, audit_info->loginuid),
> audit_info->sessionid);
>
> + lsmblob_init(&le, audit_info->secid);
> if (audit_info->secid != 0 &&
> - security_secid_to_secctx(audit_info->secid,
> - &secctx,
> - &secctx_len) == 0) {
> + security_secid_to_secctx(&le, &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " subj=%s", secctx);
> security_release_secctx(secctx, secctx_len);
> }
> diff --git a/security/security.c b/security/security.c
> index 44927bf13d32..561a41eccbd9 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1987,10 +1987,18 @@ int security_ismaclabel(const char *name)
> }
> EXPORT_SYMBOL(security_ismaclabel);
>
> -int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
> +int security_secid_to_secctx(struct lsmblob *l, char **secdata, u32 *seclen)
> {
> - return call_int_hook(secid_to_secctx, -EOPNOTSUPP, secid, secdata,
> - seclen);
> + struct security_hook_list *hp;
> + int rc;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
> + rc = hp->hook.secid_to_secctx(l->secid[hp->slot],
> + secdata, seclen);
> + if (rc != 0)
> + return rc;
> + }
> + return 0;
> }
> EXPORT_SYMBOL(security_secid_to_secctx);
>
> --
> 2.20.1
>
--
Kees Cook
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