On 12/16/19 5:36 PM, Casey Schaufler wrote:
Change the security_kernel_act_as interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its only caller, set_security_override,
to do the same. Change that one's only caller,
set_security_override_from_ctx, to call it with the new
parameter type.
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Same question re the WARN_ON, but otherwise:
Acked-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
---
include/linux/cred.h | 3 ++-
include/linux/security.h | 5 +++--
kernel/cred.c | 10 ++++++----
security/security.c | 14 ++++++++++++--
4 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 18639c069263..03ae0182cba6 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -18,6 +18,7 @@
struct cred;
struct inode;
+struct lsmblob;
/*
* COW Supplementary groups list
@@ -165,7 +166,7 @@ extern const struct cred *override_creds(const struct cred *);
extern void revert_creds(const struct cred *);
extern struct cred *prepare_kernel_cred(struct task_struct *);
extern int change_create_files_as(struct cred *, struct inode *);
-extern int set_security_override(struct cred *, u32);
+extern int set_security_override(struct cred *, struct lsmblob *);
extern int set_security_override_from_ctx(struct cred *, const char *);
extern int set_create_files_as(struct cred *, struct inode *);
extern int cred_fscmp(const struct cred *, const struct cred *);
diff --git a/include/linux/security.h b/include/linux/security.h
index 9c6dbe248eaf..322ed9622819 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -437,7 +437,7 @@ void security_cred_free(struct cred *cred);
int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
void security_transfer_creds(struct cred *new, const struct cred *old);
void security_cred_getsecid(const struct cred *c, u32 *secid);
-int security_kernel_act_as(struct cred *new, u32 secid);
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
int security_kernel_create_files_as(struct cred *new, struct inode *inode);
int security_kernel_module_request(char *kmod_name);
int security_kernel_load_data(enum kernel_load_data_id id);
@@ -1043,7 +1043,8 @@ static inline void security_transfer_creds(struct cred *new,
{
}
-static inline int security_kernel_act_as(struct cred *cred, u32 secid)
+static inline int security_kernel_act_as(struct cred *cred,
+ struct lsmblob *blob)
{
return 0;
}
diff --git a/kernel/cred.c b/kernel/cred.c
index c0a4c12d38b2..846ac4b23c16 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -732,14 +732,14 @@ EXPORT_SYMBOL(prepare_kernel_cred);
/**
* set_security_override - Set the security ID in a set of credentials
* @new: The credentials to alter
- * @secid: The LSM security ID to set
+ * @blob: The LSM security information to set
*
* Set the LSM security ID in a set of credentials so that the subjective
* security is overridden when an alternative set of credentials is used.
*/
-int set_security_override(struct cred *new, u32 secid)
+int set_security_override(struct cred *new, struct lsmblob *blob)
{
- return security_kernel_act_as(new, secid);
+ return security_kernel_act_as(new, blob);
}
EXPORT_SYMBOL(set_security_override);
@@ -755,6 +755,7 @@ EXPORT_SYMBOL(set_security_override);
*/
int set_security_override_from_ctx(struct cred *new, const char *secctx)
{
+ struct lsmblob blob;
u32 secid;
int ret;
@@ -762,7 +763,8 @@ int set_security_override_from_ctx(struct cred *new, const char *secctx)
if (ret < 0)
return ret;
- return set_security_override(new, secid);
+ lsmblob_init(&blob, secid);
+ return set_security_override(new, &blob);
}
EXPORT_SYMBOL(set_security_override_from_ctx);
diff --git a/security/security.c b/security/security.c
index bfea9739c084..cee032b5ce29 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1615,9 +1615,19 @@ void security_cred_getsecid(const struct cred *c, u32 *secid)
}
EXPORT_SYMBOL(security_cred_getsecid);
-int security_kernel_act_as(struct cred *new, u32 secid)
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob)
{
- return call_int_hook(kernel_act_as, 0, new, secid);
+ struct security_hook_list *hp;
+ int rc;
+
+ hlist_for_each_entry(hp, &security_hook_heads.kernel_act_as, list) {
+ if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+ continue;
+ rc = hp->hook.kernel_act_as(new, blob->secid[hp->lsmid->slot]);
+ if (rc != 0)
+ return rc;
+ }
+ return 0;
}
int security_kernel_create_files_as(struct cred *new, struct inode *inode)
