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Infrastructure management of the cred security blob

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Move management of the cred security blob out of the
security modules and into the security infrastructre.
Instead of allocating and freeing space the security
modules tell the infrastructure how much space they
require.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[kees: adjusted for ordered init series]
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Casey Schaufler
2018-11-12 09:30:56 -08:00
committed by Kees Cook
parent 43fc460907
commit bbd3662a83
11 changed files with 162 additions and 102 deletions
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4
security/apparmor/include/cred.h
View File

@@ -25,7 +25,7 @@
static inline struct aa_label *cred_label(const struct cred *cred)
{
struct aa_label **blob = cred->security;
struct aa_label **blob = cred->security + apparmor_blob_sizes.lbs_cred;
AA_BUG(!blob);
return *blob;
@@ -34,7 +34,7 @@ static inline struct aa_label *cred_label(const struct cred *cred)
static inline void set_cred_label(const struct cred *cred,
struct aa_label *label)
{
struct aa_label **blob = cred->security;
struct aa_label **blob = cred->security + apparmor_blob_sizes.lbs_cred;
AA_BUG(!blob);
*blob = label;

4
security/apparmor/include/lib.h
View File

@@ -16,6 +16,7 @@
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/lsm_hooks.h>
#include "match.h"
@@ -55,6 +56,9 @@ const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
size_t *ns_len);
void aa_info_message(const char *str);
/* Security blob offsets */
extern struct lsm_blob_sizes apparmor_blob_sizes;
/**
* aa_strneq - compare null terminated @str to a non null terminated substring
* @str: a null terminated string

9
security/apparmor/lsm.c
View File

@@ -1151,6 +1151,13 @@ static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb,
}
#endif
/*
* The cred blob is a pointer to, not an instance of, an aa_task_ctx.
*/
struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
.lbs_cred = sizeof(struct aa_task_ctx *),
};
static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
@@ -1485,6 +1492,7 @@ static int __init set_init_ctx(void)
if (!ctx)
return -ENOMEM;
lsm_early_cred(cred);
set_cred_label(cred, aa_get_label(ns_unconfined(root_ns)));
task_ctx(current) = ctx;
@@ -1725,5 +1733,6 @@ DEFINE_LSM(apparmor) = {
.name = "apparmor",
.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
.enabled = &apparmor_enabled,
.blobs = &apparmor_blob_sizes,
.init = apparmor_init,
};