[PATCH v10 06/25] LSM: Use lsmblob in security_secctx_to_secid
Casey Schaufler
casey at schaufler-ca.com
Thu Oct 24 20:52:09 UTC 2019
Change security_secctx_to_secid() to fill in a lsmblob instead
of a u32 secid. Multiple LSMs may be able to interpret the
string, and this allows for setting whichever secid is
appropriate. In some cases there is scaffolding where other
interfaces have yet to be converted.
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>
---
include/linux/security.h | 5 +++--
kernel/cred.c | 4 +---
net/netfilter/nft_meta.c | 13 ++++++-------
net/netfilter/xt_SECMARK.c | 5 ++++-
net/netlabel/netlabel_unlabeled.c | 14 ++++++++------
security/security.c | 18 +++++++++++++++---
6 files changed, 37 insertions(+), 22 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index 02ff6250bf2b..2cc0588311b9 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -439,7 +439,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
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_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+ struct lsmblob *blob);
void security_release_secctx(char *secdata, u32 seclen);
void security_inode_invalidate_secctx(struct inode *inode);
@@ -1222,7 +1223,7 @@ static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *secle
static inline int security_secctx_to_secid(const char *secdata,
u32 seclen,
- u32 *secid)
+ struct lsmblob *blob)
{
return -EOPNOTSUPP;
}
diff --git a/kernel/cred.c b/kernel/cred.c
index 71c14dda107e..d70a2c02ced4 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -725,14 +725,12 @@ EXPORT_SYMBOL(set_security_override);
int set_security_override_from_ctx(struct cred *new, const char *secctx)
{
struct lsmblob blob;
- u32 secid;
int ret;
- ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
+ ret = security_secctx_to_secid(secctx, strlen(secctx), &blob);
if (ret < 0)
return ret;
- lsmblob_init(&blob, secid);
return set_security_override(new, &blob);
}
EXPORT_SYMBOL(set_security_override_from_ctx);
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 987d2d6ce624..054fb4b48d51 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -576,21 +576,20 @@ static const struct nla_policy nft_secmark_policy[NFTA_SECMARK_MAX + 1] = {
static int nft_secmark_compute_secid(struct nft_secmark *priv)
{
- u32 tmp_secid = 0;
+ struct lsmblob blob;
int err;
- err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &tmp_secid);
+ err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &blob);
if (err)
return err;
- if (!tmp_secid)
- return -ENOENT;
-
- err = security_secmark_relabel_packet(tmp_secid);
+ /* Using le[0] is scaffolding */
+ err = security_secmark_relabel_packet(blob.secid[0]);
if (err)
return err;
- priv->secid = tmp_secid;
+ /* Using le[0] is scaffolding */
+ priv->secid = blob.secid[0];
return 0;
}
diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
index f16202d26c20..8081fadc30e9 100644
--- a/net/netfilter/xt_SECMARK.c
+++ b/net/netfilter/xt_SECMARK.c
@@ -49,13 +49,14 @@ secmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
static int checkentry_lsm(struct xt_secmark_target_info *info)
{
+ struct lsmblob blob;
int err;
info->secctx[SECMARK_SECCTX_MAX - 1] = '\0';
info->secid = 0;
err = security_secctx_to_secid(info->secctx, strlen(info->secctx),
- &info->secid);
+ &blob);
if (err) {
if (err == -EINVAL)
pr_info_ratelimited("invalid security context \'%s\'\n",
@@ -63,6 +64,8 @@ static int checkentry_lsm(struct xt_secmark_target_info *info)
return err;
}
+ /* scaffolding during the transition */
+ info->secid = blob.secid[0];
if (!info->secid) {
pr_info_ratelimited("unable to map security context \'%s\'\n",
info->secctx);
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index c92894c3e40a..2976370e41aa 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -895,7 +895,7 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
void *addr;
void *mask;
u32 addr_len;
- u32 secid;
+ struct lsmblob blob;
struct netlbl_audit audit_info;
/* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -919,12 +919,13 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
ret_val = security_secctx_to_secid(
nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
- &secid);
+ &blob);
if (ret_val != 0)
return ret_val;
+ /* scaffolding with the [0] */
return netlbl_unlhsh_add(&init_net,
- dev_name, addr, mask, addr_len, secid,
+ dev_name, addr, mask, addr_len, blob.secid[0],
&audit_info);
}
@@ -946,7 +947,7 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
void *addr;
void *mask;
u32 addr_len;
- u32 secid;
+ struct lsmblob blob;
struct netlbl_audit audit_info;
/* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -968,12 +969,13 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
ret_val = security_secctx_to_secid(
nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
- &secid);
+ &blob);
if (ret_val != 0)
return ret_val;
+ /* scaffolding with the [0] */
return netlbl_unlhsh_add(&init_net,
- NULL, addr, mask, addr_len, secid,
+ NULL, addr, mask, addr_len, blob.secid[0],
&audit_info);
}
diff --git a/security/security.c b/security/security.c
index bd685be33b56..8e4f41d9af0f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1921,10 +1921,22 @@ int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
}
EXPORT_SYMBOL(security_secid_to_secctx);
-int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+ struct lsmblob *blob)
{
- *secid = 0;
- return call_int_hook(secctx_to_secid, 0, secdata, seclen, secid);
+ struct security_hook_list *hp;
+ int rc;
+
+ lsmblob_init(blob, 0);
+ hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
+ if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+ continue;
+ rc = hp->hook.secctx_to_secid(secdata, seclen,
+ &blob->secid[hp->lsmid->slot]);
+ if (rc != 0)
+ return rc;
+ }
+ return 0;
}
EXPORT_SYMBOL(security_secctx_to_secid);
--
2.20.1
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