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Subject[PATCH 3.2 017/104] SELinux: security_load_policy: Silence frame-larger-than warning
3.2.101-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Tim Gardner <tim.gardner@canonical.com>

commit b5495b4217d3fa64deac479db83dbede149af7d8 upstream.

Dynamically allocate a couple of the larger stack variables in order to
reduce the stack footprint below 1024. gcc-4.8

security/selinux/ss/services.c: In function 'security_load_policy':
security/selinux/ss/services.c:1964:1: warning: the frame size of 1104 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}

Also silence a couple of checkpatch warnings at the same time.

WARNING: sizeof policydb should be sizeof(policydb)
+ memcpy(oldpolicydb, &policydb, sizeof policydb);

WARNING: sizeof policydb should be sizeof(policydb)
+ memcpy(&policydb, newpolicydb, sizeof policydb);

Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
security/selinux/ss/services.c | 54 +++++++++++++++++++++++++-----------------
1 file changed, 32 insertions(+), 22 deletions(-)

--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1806,7 +1806,7 @@ static int security_preserve_bools(struc
*/
int security_load_policy(void *data, size_t len)
{
- struct policydb oldpolicydb, newpolicydb;
+ struct policydb *oldpolicydb, *newpolicydb;
struct sidtab oldsidtab, newsidtab;
struct selinux_mapping *oldmap, *map = NULL;
struct convert_context_args args;
@@ -1815,12 +1815,19 @@ int security_load_policy(void *data, siz
int rc = 0;
struct policy_file file = { data, len }, *fp = &file;

+ oldpolicydb = kzalloc(2 * sizeof(*oldpolicydb), GFP_KERNEL);
+ if (!oldpolicydb) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ newpolicydb = oldpolicydb + 1;
+
if (!ss_initialized) {
avtab_cache_init();
rc = policydb_read(&policydb, fp);
if (rc) {
avtab_cache_destroy();
- return rc;
+ goto out;
}

policydb.len = len;
@@ -1830,14 +1837,14 @@ int security_load_policy(void *data, siz
if (rc) {
policydb_destroy(&policydb);
avtab_cache_destroy();
- return rc;
+ goto out;
}

rc = policydb_load_isids(&policydb, &sidtab);
if (rc) {
policydb_destroy(&policydb);
avtab_cache_destroy();
- return rc;
+ goto out;
}

security_load_policycaps();
@@ -1849,36 +1856,36 @@ int security_load_policy(void *data, siz
selinux_status_update_policyload(seqno);
selinux_netlbl_cache_invalidate();
selinux_xfrm_notify_policyload();
- return 0;
+ goto out;
}

#if 0
sidtab_hash_eval(&sidtab, "sids");
#endif

- rc = policydb_read(&newpolicydb, fp);
+ rc = policydb_read(newpolicydb, fp);
if (rc)
- return rc;
+ goto out;

- newpolicydb.len = len;
+ newpolicydb->len = len;
/* If switching between different policy types, log MLS status */
- if (policydb.mls_enabled && !newpolicydb.mls_enabled)
+ if (policydb.mls_enabled && !newpolicydb->mls_enabled)
printk(KERN_INFO "SELinux: Disabling MLS support...\n");
- else if (!policydb.mls_enabled && newpolicydb.mls_enabled)
+ else if (!policydb.mls_enabled && newpolicydb->mls_enabled)
printk(KERN_INFO "SELinux: Enabling MLS support...\n");

- rc = policydb_load_isids(&newpolicydb, &newsidtab);
+ rc = policydb_load_isids(newpolicydb, &newsidtab);
if (rc) {
printk(KERN_ERR "SELinux: unable to load the initial SIDs\n");
- policydb_destroy(&newpolicydb);
- return rc;
+ policydb_destroy(newpolicydb);
+ goto out;
}

- rc = selinux_set_mapping(&newpolicydb, secclass_map, &map, &map_size);
+ rc = selinux_set_mapping(newpolicydb, secclass_map, &map, &map_size);
if (rc)
goto err;

- rc = security_preserve_bools(&newpolicydb);
+ rc = security_preserve_bools(newpolicydb);
if (rc) {
printk(KERN_ERR "SELinux: unable to preserve booleans\n");
goto err;
@@ -1896,7 +1903,7 @@ int security_load_policy(void *data, siz
* in the new SID table.
*/
args.oldp = &policydb;
- args.newp = &newpolicydb;
+ args.newp = newpolicydb;
rc = sidtab_map(&newsidtab, convert_context, &args);
if (rc) {
printk(KERN_ERR "SELinux: unable to convert the internal"
@@ -1906,12 +1913,12 @@ int security_load_policy(void *data, siz
}

/* Save the old policydb and SID table to free later. */
- memcpy(&oldpolicydb, &policydb, sizeof policydb);
+ memcpy(oldpolicydb, &policydb, sizeof(policydb));
sidtab_set(&oldsidtab, &sidtab);

/* Install the new policydb and SID table. */
write_lock_irq(&policy_rwlock);
- memcpy(&policydb, &newpolicydb, sizeof policydb);
+ memcpy(&policydb, newpolicydb, sizeof(policydb));
sidtab_set(&sidtab, &newsidtab);
security_load_policycaps();
oldmap = current_mapping;
@@ -1921,7 +1928,7 @@ int security_load_policy(void *data, siz
write_unlock_irq(&policy_rwlock);

/* Free the old policydb and SID table. */
- policydb_destroy(&oldpolicydb);
+ policydb_destroy(oldpolicydb);
sidtab_destroy(&oldsidtab);
kfree(oldmap);

@@ -1931,14 +1938,17 @@ int security_load_policy(void *data, siz
selinux_netlbl_cache_invalidate();
selinux_xfrm_notify_policyload();

- return 0;
+ rc = 0;
+ goto out;

err:
kfree(map);
sidtab_destroy(&newsidtab);
- policydb_destroy(&newpolicydb);
- return rc;
+ policydb_destroy(newpolicydb);

+out:
+ kfree(oldpolicydb);
+ return rc;
}

size_t security_policydb_len(void)
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