[PATCH v13 19/25] NET: Store LSM netlabel data in a lsmblob
Stephen Smalley
sds at tycho.nsa.gov
Tue Jan 7 19:25:56 UTC 2020
On 12/24/19 6:59 PM, Casey Schaufler wrote:
> Netlabel uses LSM interfaces requiring an lsmblob and
> the internal storage is used to pass information between
> these interfaces, so change the internal data from a secid
> to a lsmblob. Update the netlabel interfaces and their
> callers to accommodate the change. This requires that the
> modules using netlabel use the lsm_id.slot to access the
> correct secid when using netlabel.
>
> Reviewed-by: Kees Cook <keescook at chromium.org>
> Reviewed-by: John Johansen <john.johansen at canonical.com>
> Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
Why is this needed for stacking AppArmor? AA doesn't use NetLabel, at
least not upstream AFAICS.
> ---
> include/net/netlabel.h | 8 ++--
> net/ipv4/cipso_ipv4.c | 23 +++++++-----
> net/netlabel/netlabel_kapi.c | 6 +--
> net/netlabel/netlabel_unlabeled.c | 57 +++++++++++------------------
> net/netlabel/netlabel_unlabeled.h | 2 +-
> security/selinux/hooks.c | 2 +-
> security/selinux/include/security.h | 1 +
> security/selinux/netlabel.c | 2 +-
> security/selinux/ss/services.c | 4 +-
> security/smack/smack.h | 1 +
> security/smack/smack_lsm.c | 5 ++-
> security/smack/smackfs.c | 10 +++--
> 12 files changed, 59 insertions(+), 62 deletions(-)
>
> diff --git a/include/net/netlabel.h b/include/net/netlabel.h
> index 43ae50337685..73fc25b4042b 100644
> --- a/include/net/netlabel.h
> +++ b/include/net/netlabel.h
> @@ -166,7 +166,7 @@ struct netlbl_lsm_catmap {
> * @attr.mls: MLS sensitivity label
> * @attr.mls.cat: MLS category bitmap
> * @attr.mls.lvl: MLS sensitivity level
> - * @attr.secid: LSM specific secid token
> + * @attr.lsmblob: LSM specific data
> *
> * Description:
> * This structure is used to pass security attributes between NetLabel and the
> @@ -201,7 +201,7 @@ struct netlbl_lsm_secattr {
> struct netlbl_lsm_catmap *cat;
> u32 lvl;
> } mls;
> - u32 secid;
> + struct lsmblob lsmblob;
> } attr;
> };
>
> @@ -415,7 +415,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
> const void *addr,
> const void *mask,
> u16 family,
> - u32 secid,
> + struct lsmblob *lsmblob,
> struct netlbl_audit *audit_info);
> int netlbl_cfg_unlbl_static_del(struct net *net,
> const char *dev_name,
> @@ -523,7 +523,7 @@ static inline int netlbl_cfg_unlbl_static_add(struct net *net,
> const void *addr,
> const void *mask,
> u16 family,
> - u32 secid,
> + struct lsmblob *lsmblob,
> struct netlbl_audit *audit_info)
> {
> return -ENOSYS;
> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 376882215919..adb9dffc3952 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -106,15 +106,17 @@ int cipso_v4_rbm_strictvalid = 1;
> /* Base length of the local tag (non-standard tag).
> * Tag definition (may change between kernel versions)
> *
> - * 0 8 16 24 32
> - * +----------+----------+----------+----------+
> - * | 10000000 | 00000110 | 32-bit secid value |
> - * +----------+----------+----------+----------+
> - * | in (host byte order)|
> - * +----------+----------+
> - *
> + * 0 8 16 16 + sizeof(struct lsmblob)
> + * +----------+----------+---------------------+
> + * | 10000000 | 00000110 | LSM blob data |
> + * +----------+----------+---------------------+
> + *
> + * All secid and flag fields are in host byte order.
> + * The lsmblob structure size varies depending on which
> + * Linux security modules are built in the kernel.
> + * The data is opaque.
> */
> -#define CIPSO_V4_TAG_LOC_BLEN 6
> +#define CIPSO_V4_TAG_LOC_BLEN (2 + sizeof(struct lsmblob))
>
> /*
> * Helper Functions
> @@ -1467,7 +1469,8 @@ static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
>
> buffer[0] = CIPSO_V4_TAG_LOCAL;
> buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
> - *(u32 *)&buffer[2] = secattr->attr.secid;
> + memcpy(&buffer[2], &secattr->attr.lsmblob,
> + sizeof(secattr->attr.lsmblob));
>
> return CIPSO_V4_TAG_LOC_BLEN;
> }
> @@ -1487,7 +1490,7 @@ static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
> const unsigned char *tag,
> struct netlbl_lsm_secattr *secattr)
> {
> - secattr->attr.secid = *(u32 *)&tag[2];
> + memcpy(&secattr->attr.lsmblob, &tag[2], sizeof(secattr->attr.lsmblob));
> secattr->flags |= NETLBL_SECATTR_SECID;
>
> return 0;
> diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
> index 409a3ae47ce2..f2ebd43a7992 100644
> --- a/net/netlabel/netlabel_kapi.c
> +++ b/net/netlabel/netlabel_kapi.c
> @@ -196,7 +196,7 @@ int netlbl_cfg_unlbl_map_add(const char *domain,
> * @addr: IP address in network byte order (struct in[6]_addr)
> * @mask: address mask in network byte order (struct in[6]_addr)
> * @family: address family
> - * @secid: LSM secid value for the entry
> + * @lsmblob: LSM data value for the entry
> * @audit_info: NetLabel audit information
> *
> * Description:
> @@ -210,7 +210,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
> const void *addr,
> const void *mask,
> u16 family,
> - u32 secid,
> + struct lsmblob *lsmblob,
> struct netlbl_audit *audit_info)
> {
> u32 addr_len;
> @@ -230,7 +230,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
>
> return netlbl_unlhsh_add(net,
> dev_name, addr, mask, addr_len,
> - secid, audit_info);
> + lsmblob, audit_info);
> }
>
> /**
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index c03fe9a4f7b9..3b0f07b59436 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -66,7 +66,7 @@ struct netlbl_unlhsh_tbl {
> #define netlbl_unlhsh_addr4_entry(iter) \
> container_of(iter, struct netlbl_unlhsh_addr4, list)
> struct netlbl_unlhsh_addr4 {
> - u32 secid;
> + struct lsmblob lsmblob;
>
> struct netlbl_af4list list;
> struct rcu_head rcu;
> @@ -74,7 +74,7 @@ struct netlbl_unlhsh_addr4 {
> #define netlbl_unlhsh_addr6_entry(iter) \
> container_of(iter, struct netlbl_unlhsh_addr6, list)
> struct netlbl_unlhsh_addr6 {
> - u32 secid;
> + struct lsmblob lsmblob;
>
> struct netlbl_af6list list;
> struct rcu_head rcu;
> @@ -219,7 +219,7 @@ static struct netlbl_unlhsh_iface *netlbl_unlhsh_search_iface(int ifindex)
> * @iface: the associated interface entry
> * @addr: IPv4 address in network byte order
> * @mask: IPv4 address mask in network byte order
> - * @secid: LSM secid value for entry
> + * @lsmblob: LSM data value for entry
> *
> * Description:
> * Add a new address entry into the unlabeled connection hash table using the
> @@ -230,7 +230,7 @@ static struct netlbl_unlhsh_iface *netlbl_unlhsh_search_iface(int ifindex)
> static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
> const struct in_addr *addr,
> const struct in_addr *mask,
> - u32 secid)
> + struct lsmblob *lsmblob)
> {
> int ret_val;
> struct netlbl_unlhsh_addr4 *entry;
> @@ -242,7 +242,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
> entry->list.addr = addr->s_addr & mask->s_addr;
> entry->list.mask = mask->s_addr;
> entry->list.valid = 1;
> - entry->secid = secid;
> + entry->lsmblob = *lsmblob;
>
> spin_lock(&netlbl_unlhsh_lock);
> ret_val = netlbl_af4list_add(&entry->list, &iface->addr4_list);
> @@ -259,7 +259,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
> * @iface: the associated interface entry
> * @addr: IPv6 address in network byte order
> * @mask: IPv6 address mask in network byte order
> - * @secid: LSM secid value for entry
> + * @lsmblob: LSM data value for entry
> *
> * Description:
> * Add a new address entry into the unlabeled connection hash table using the
> @@ -270,7 +270,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
> static int netlbl_unlhsh_add_addr6(struct netlbl_unlhsh_iface *iface,
> const struct in6_addr *addr,
> const struct in6_addr *mask,
> - u32 secid)
> + struct lsmblob *lsmblob)
> {
> int ret_val;
> struct netlbl_unlhsh_addr6 *entry;
> @@ -286,7 +286,7 @@ static int netlbl_unlhsh_add_addr6(struct netlbl_unlhsh_iface *iface,
> entry->list.addr.s6_addr32[3] &= mask->s6_addr32[3];
> entry->list.mask = *mask;
> entry->list.valid = 1;
> - entry->secid = secid;
> + entry->lsmblob = *lsmblob;
>
> spin_lock(&netlbl_unlhsh_lock);
> ret_val = netlbl_af6list_add(&entry->list, &iface->addr6_list);
> @@ -365,7 +365,7 @@ int netlbl_unlhsh_add(struct net *net,
> const void *addr,
> const void *mask,
> u32 addr_len,
> - u32 secid,
> + struct lsmblob *lsmblob,
> struct netlbl_audit *audit_info)
> {
> int ret_val;
> @@ -374,7 +374,6 @@ int netlbl_unlhsh_add(struct net *net,
> struct netlbl_unlhsh_iface *iface;
> struct audit_buffer *audit_buf = NULL;
> struct lsmcontext context;
> - struct lsmblob blob;
>
> if (addr_len != sizeof(struct in_addr) &&
> addr_len != sizeof(struct in6_addr))
> @@ -407,7 +406,7 @@ int netlbl_unlhsh_add(struct net *net,
> const struct in_addr *addr4 = addr;
> const struct in_addr *mask4 = mask;
>
> - ret_val = netlbl_unlhsh_add_addr4(iface, addr4, mask4, secid);
> + ret_val = netlbl_unlhsh_add_addr4(iface, addr4, mask4, lsmblob);
> if (audit_buf != NULL)
> netlbl_af4list_audit_addr(audit_buf, 1,
> dev_name,
> @@ -420,7 +419,7 @@ int netlbl_unlhsh_add(struct net *net,
> const struct in6_addr *addr6 = addr;
> const struct in6_addr *mask6 = mask;
>
> - ret_val = netlbl_unlhsh_add_addr6(iface, addr6, mask6, secid);
> + ret_val = netlbl_unlhsh_add_addr6(iface, addr6, mask6, lsmblob);
> if (audit_buf != NULL)
> netlbl_af6list_audit_addr(audit_buf, 1,
> dev_name,
> @@ -437,8 +436,7 @@ int netlbl_unlhsh_add(struct net *net,
> unlhsh_add_return:
> rcu_read_unlock();
> if (audit_buf != NULL) {
> - lsmblob_init(&blob, secid);
> - if (security_secid_to_secctx(&blob, &context) == 0) {
> + if (security_secid_to_secctx(lsmblob, &context) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s",
> context.context);
> security_release_secctx(&context);
> @@ -473,7 +471,6 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> struct lsmcontext context;
> - struct lsmblob blob;
>
> spin_lock(&netlbl_unlhsh_lock);
> list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
> @@ -493,10 +490,8 @@ 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(&blob, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(&blob, &context) == 0) {
> + security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s",
> context.context);
> security_release_secctx(&context);
> @@ -537,7 +532,6 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> struct lsmcontext context;
> - struct lsmblob blob;
>
> spin_lock(&netlbl_unlhsh_lock);
> list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
> @@ -556,10 +550,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> addr, mask);
> if (dev != NULL)
> dev_put(dev);
> - if (entry != NULL)
> - lsmblob_init(&blob, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(&blob, &context) == 0) {
> + security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s",
> context.context);
> security_release_secctx(&context);
> @@ -913,9 +905,8 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
> if (ret_val != 0)
> return ret_val;
>
> - /* scaffolding with the [0] */
> return netlbl_unlhsh_add(&init_net,
> - dev_name, addr, mask, addr_len, blob.secid[0],
> + dev_name, addr, mask, addr_len, &blob,
> &audit_info);
> }
>
> @@ -963,10 +954,8 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
> if (ret_val != 0)
> return ret_val;
>
> - /* scaffolding with the [0] */
> return netlbl_unlhsh_add(&init_net,
> - NULL, addr, mask, addr_len, blob.secid[0],
> - &audit_info);
> + NULL, addr, mask, addr_len, &blob, &audit_info);
> }
>
> /**
> @@ -1078,8 +1067,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> struct net_device *dev;
> struct lsmcontext context;
> void *data;
> - u32 secid;
> - struct lsmblob blob;
> + struct lsmblob *lsmb;
>
> data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
> cb_arg->seq, &netlbl_unlabel_gnl_family,
> @@ -1117,7 +1105,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> if (ret_val != 0)
> goto list_cb_failure;
>
> - secid = addr4->secid;
> + lsmb = (struct lsmblob *)&addr4->lsmblob;
> } else {
> ret_val = nla_put_in6_addr(cb_arg->skb,
> NLBL_UNLABEL_A_IPV6ADDR,
> @@ -1131,11 +1119,10 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> if (ret_val != 0)
> goto list_cb_failure;
>
> - secid = addr6->secid;
> + lsmb = (struct lsmblob *)&addr6->lsmblob;
> }
>
> - lsmblob_init(&blob, secid);
> - ret_val = security_secid_to_secctx(&blob, &context);
> + ret_val = security_secid_to_secctx(lsmb, &context);
> if (ret_val != 0)
> goto list_cb_failure;
> ret_val = nla_put(cb_arg->skb,
> @@ -1487,7 +1474,7 @@ int netlbl_unlabel_getattr(const struct sk_buff *skb,
> &iface->addr4_list);
> if (addr4 == NULL)
> goto unlabel_getattr_nolabel;
> - secattr->attr.secid = netlbl_unlhsh_addr4_entry(addr4)->secid;
> + secattr->attr.lsmblob = netlbl_unlhsh_addr4_entry(addr4)->lsmblob;
> break;
> }
> #if IS_ENABLED(CONFIG_IPV6)
> @@ -1500,7 +1487,7 @@ int netlbl_unlabel_getattr(const struct sk_buff *skb,
> &iface->addr6_list);
> if (addr6 == NULL)
> goto unlabel_getattr_nolabel;
> - secattr->attr.secid = netlbl_unlhsh_addr6_entry(addr6)->secid;
> + secattr->attr.lsmblob = netlbl_unlhsh_addr6_entry(addr6)->lsmblob;
> break;
> }
> #endif /* IPv6 */
> diff --git a/net/netlabel/netlabel_unlabeled.h b/net/netlabel/netlabel_unlabeled.h
> index 058e3a285d56..168920780994 100644
> --- a/net/netlabel/netlabel_unlabeled.h
> +++ b/net/netlabel/netlabel_unlabeled.h
> @@ -211,7 +211,7 @@ int netlbl_unlhsh_add(struct net *net,
> const void *addr,
> const void *mask,
> u32 addr_len,
> - u32 secid,
> + struct lsmblob *lsmblob,
> struct netlbl_audit *audit_info);
> int netlbl_unlhsh_remove(struct net *net,
> const char *dev_name,
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index b8501ca3c8f3..cd4743331800 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -6871,7 +6871,7 @@ static int selinux_perf_event_write(struct perf_event *event)
> }
> #endif
>
> -static struct lsm_id selinux_lsmid __lsm_ro_after_init = {
> +struct lsm_id selinux_lsmid __lsm_ro_after_init = {
> .lsm = "selinux",
> .slot = LSMBLOB_NEEDED
> };
> diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
> index ae840634e3c7..741ba0e6dd83 100644
> --- a/security/selinux/include/security.h
> +++ b/security/selinux/include/security.h
> @@ -70,6 +70,7 @@
> struct netlbl_lsm_secattr;
>
> extern int selinux_enabled;
> +extern struct lsm_id selinux_lsmid;
>
> /* Policy capabilities */
> enum {
> diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
> index 6a94b31b5472..d8d7603ab14e 100644
> --- a/security/selinux/netlabel.c
> +++ b/security/selinux/netlabel.c
> @@ -108,7 +108,7 @@ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr(
> return NULL;
>
> if ((secattr->flags & NETLBL_SECATTR_SECID) &&
> - (secattr->attr.secid == sid))
> + (secattr->attr.lsmblob.secid[selinux_lsmid.slot] == sid))
> return secattr;
>
> return NULL;
> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> index a5813c7629c1..2b7680903b6b 100644
> --- a/security/selinux/ss/services.c
> +++ b/security/selinux/ss/services.c
> @@ -3599,7 +3599,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
> if (secattr->flags & NETLBL_SECATTR_CACHE)
> *sid = *(u32 *)secattr->cache->data;
> else if (secattr->flags & NETLBL_SECATTR_SECID)
> - *sid = secattr->attr.secid;
> + *sid = secattr->attr.lsmblob.secid[selinux_lsmid.slot];
> else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
> rc = -EIDRM;
> ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
> @@ -3672,7 +3672,7 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state,
> if (secattr->domain == NULL)
> goto out;
>
> - secattr->attr.secid = sid;
> + secattr->attr.lsmblob.secid[selinux_lsmid.slot] = sid;
> secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
> mls_export_netlbl_lvl(policydb, ctx, secattr);
> rc = mls_export_netlbl_cat(policydb, ctx, secattr);
> diff --git a/security/smack/smack.h b/security/smack/smack.h
> index 2836540f9577..6e76b6b33063 100644
> --- a/security/smack/smack.h
> +++ b/security/smack/smack.h
> @@ -316,6 +316,7 @@ void smk_destroy_label_list(struct list_head *list);
> * Shared data.
> */
> extern int smack_enabled;
> +extern struct lsm_id smack_lsmid;
> extern int smack_cipso_direct;
> extern int smack_cipso_mapped;
> extern struct smack_known *smack_net_ambient;
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 9737ead06b39..9ce67e03ac49 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -3775,7 +3775,8 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
> /*
> * Looks like a fallback, which gives us a secid.
> */
> - return smack_from_secid(sap->attr.secid);
> + return smack_from_secid(
> + sap->attr.lsmblob.secid[smack_lsmid.slot]);
> /*
> * Without guidance regarding the smack value
> * for the packet fall back on the network
> @@ -4592,7 +4593,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
> .lbs_sock = sizeof(struct socket_smack),
> };
>
> -static struct lsm_id smack_lsmid __lsm_ro_after_init = {
> +struct lsm_id smack_lsmid __lsm_ro_after_init = {
> .lsm = "smack",
> .slot = LSMBLOB_NEEDED
> };
> diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
> index e3e05c04dbd1..d10e9c96717e 100644
> --- a/security/smack/smackfs.c
> +++ b/security/smack/smackfs.c
> @@ -1122,6 +1122,7 @@ static void smk_net4addr_insert(struct smk_net4addr *new)
> static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
> size_t count, loff_t *ppos)
> {
> + struct lsmblob lsmblob;
> struct smk_net4addr *snp;
> struct sockaddr_in newname;
> char *smack;
> @@ -1253,10 +1254,13 @@ static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
> * this host so that incoming packets get labeled.
> * but only if we didn't get the special CIPSO option
> */
> - if (rc == 0 && skp != NULL)
> + if (rc == 0 && skp != NULL) {
> + lsmblob_init(&lsmblob, 0);
> + lsmblob.secid[smack_lsmid.slot] = snp->smk_label->smk_secid;
> rc = netlbl_cfg_unlbl_static_add(&init_net, NULL,
> - &snp->smk_host, &snp->smk_mask, PF_INET,
> - snp->smk_label->smk_secid, &audit_info);
> + &snp->smk_host, &snp->smk_mask, PF_INET, &lsmblob,
> + &audit_info);
> + }
>
> if (rc == 0)
> rc = count;
>
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