Re: [PATCH v22 05/23] LSM: Use lsmblob in security_secctx_to_secid
On Wed, 4 Nov 2020, Casey Schaufler wrote: > Change the security_secctx_to_secid interface to use a lsmblob > structure in place of the single u32 secid in support of > module stacking. Change its callers to do the same. > > The security module hook is unchanged, still passing back a secid. > The infrastructure passes the correct entry from the lsmblob. > > Signed-off-by: Casey Schaufler > Cc: net...@vger.kernel.org You probably need to include Netfilter maintainers specifically for this (added them + the Netfilter list). This also needs signoffs from LSM owners. -- James Morris
[PATCH v22 05/23] LSM: Use lsmblob in security_secctx_to_secid
Change the security_secctx_to_secid interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its callers to do the same.
The security module hook is unchanged, still passing back a secid.
The infrastructure passes the correct entry from the lsmblob.
Signed-off-by: Casey Schaufler
Cc: net...@vger.kernel.org
---
include/linux/security.h | 26 ++--
kernel/cred.c | 4 +---
net/netfilter/nft_meta.c | 10
net/netfilter/xt_SECMARK.c| 7 +-
net/netlabel/netlabel_unlabeled.c | 23 +++---
security/security.c | 40 ++-
6 files changed, 85 insertions(+), 25 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index 948d12a5eb25..0766725a6b21 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -191,6 +191,27 @@ static inline bool lsmblob_equal(struct lsmblob *bloba,
struct lsmblob *blobb)
return !memcmp(bloba, blobb, sizeof(*bloba));
}
+/**
+ * lsmblob_value - find the first non-zero value in an lsmblob structure.
+ * @blob: Pointer to the data
+ *
+ * This needs to be used with extreme caution, as the cases where
+ * it is appropriate are rare.
+ *
+ * Return the first secid value set in the lsmblob.
+ * There should only be one.
+ */
+static inline u32 lsmblob_value(const struct lsmblob *blob)
+{
+ int i;
+
+ for (i = 0; i < LSMBLOB_ENTRIES; i++)
+ if (blob->secid[i])
+ return blob->secid[i];
+
+ return 0;
+}
+
/* These functions are in security/commoncap.c */
extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
int cap, unsigned int opts);
@@ -508,7 +529,8 @@ 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);
int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
@@ -1335,7 +1357,7 @@ 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 22e0e7cbefde..848306c7d823 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -757,14 +757,12 @@ 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 b37bd02448d8..f1b9b0021414 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -811,21 +811,21 @@ 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)
+ if (!lsmblob_is_set(&blob))
return -ENOENT;
- err = security_secmark_relabel_packet(tmp_secid);
+ err = security_secmark_relabel_packet(lsmblob_value(&blob));
if (err)
return err;
- priv->secid = tmp_secid;
+ priv->secid = lsmblob_value(&blob);
return 0;
}
diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
index 75625d13e976..9845d98e6b77 100644
--- a/net/netfilter/xt_SECMARK.c
+++ b/net/netfilter/xt_SECMARK.c
@@ -43,13 +43,14 @@ 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, s
[PATCH v22 05/23] LSM: Use lsmblob in security_secctx_to_secid
Change the security_secctx_to_secid interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its callers to do the same.
The security module hook is unchanged, still passing back a secid.
The infrastructure passes the correct entry from the lsmblob.
Signed-off-by: Casey Schaufler
Cc: net...@vger.kernel.org
---
include/linux/security.h | 26 ++--
kernel/cred.c | 4 +---
net/netfilter/nft_meta.c | 10
net/netfilter/xt_SECMARK.c| 7 +-
net/netlabel/netlabel_unlabeled.c | 23 +++---
security/security.c | 40 ++-
6 files changed, 85 insertions(+), 25 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index 948d12a5eb25..0766725a6b21 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -191,6 +191,27 @@ static inline bool lsmblob_equal(struct lsmblob *bloba,
struct lsmblob *blobb)
return !memcmp(bloba, blobb, sizeof(*bloba));
}
+/**
+ * lsmblob_value - find the first non-zero value in an lsmblob structure.
+ * @blob: Pointer to the data
+ *
+ * This needs to be used with extreme caution, as the cases where
+ * it is appropriate are rare.
+ *
+ * Return the first secid value set in the lsmblob.
+ * There should only be one.
+ */
+static inline u32 lsmblob_value(const struct lsmblob *blob)
+{
+ int i;
+
+ for (i = 0; i < LSMBLOB_ENTRIES; i++)
+ if (blob->secid[i])
+ return blob->secid[i];
+
+ return 0;
+}
+
/* These functions are in security/commoncap.c */
extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
int cap, unsigned int opts);
@@ -508,7 +529,8 @@ 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);
int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
@@ -1335,7 +1357,7 @@ 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 22e0e7cbefde..848306c7d823 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -757,14 +757,12 @@ 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 b37bd02448d8..f1b9b0021414 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -811,21 +811,21 @@ 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)
+ if (!lsmblob_is_set(&blob))
return -ENOENT;
- err = security_secmark_relabel_packet(tmp_secid);
+ err = security_secmark_relabel_packet(lsmblob_value(&blob));
if (err)
return err;
- priv->secid = tmp_secid;
+ priv->secid = lsmblob_value(&blob);
return 0;
}
diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
index 75625d13e976..9845d98e6b77 100644
--- a/net/netfilter/xt_SECMARK.c
+++ b/net/netfilter/xt_SECMARK.c
@@ -43,13 +43,14 @@ 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, s
