On 5/14/2018 8:04 AM, Stephen Smalley wrote:
> On 05/10/2018 08:53 PM, Casey Schaufler wrote:
>> From: Casey Schaufler <ca...@schaufler-ca.com>
>> Date: Thu, 10 May 2018 14:23:27 -0700
>> Subject: [PATCH 10/23] LSM: Infrastructure management of the inode security
>> blob
>>
>> Move management of the inode->i_security blob out
>> of the individual security modules and into the security
>> infrastructure. Instead of allocating the blobs from within
>> the modules the modules tell the infrastructure how much
>> space is required, and the space is allocated there.
>>
>> Signed-off-by: Casey Schaufler <ca...@schaufler-ca.com>
>> ---
>> include/linux/lsm_hooks.h | 3 ++
>> security/security.c | 85
>> +++++++++++++++++++++++++++++++++++++--
>> security/selinux/hooks.c | 32 +--------------
>> security/selinux/include/objsec.h | 5 +--
>> security/smack/smack_lsm.c | 70 +++++---------------------------
>> 5 files changed, 99 insertions(+), 96 deletions(-)
>> <SNIP>
>> diff --git a/security/security.c b/security/security.c
>> index b414186ad45f..02df9b608b7e 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -41,6 +41,7 @@ struct security_hook_heads security_hook_heads
>> __lsm_ro_after_init;
>> static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
>>
>> static struct kmem_cache *lsm_file_cache;
>> +static struct kmem_cache *lsm_inode_cache;
>>
>> char *lsm_names;
>> static struct lsm_blob_sizes blob_sizes;
>> @@ -98,6 +99,10 @@ int __init security_init(void)
>> lsm_file_cache = kmem_cache_create("lsm_file_cache",
>> blob_sizes.lbs_file, 0,
>> SLAB_PANIC, NULL);
>> + if (blob_sizes.lbs_inode)
>> + lsm_inode_cache = kmem_cache_create("lsm_inode_cache",
>> + blob_sizes.lbs_inode, 0,
>> + SLAB_PANIC, NULL);
>> /*
>> * The second call to a module specific init function
>> * adds hooks to the hook lists and does any other early
>> @@ -108,8 +113,9 @@ int __init security_init(void)
>> #ifdef CONFIG_SECURITY_LSM_DEBUG
>> pr_info("LSM: cred blob size = %d\n", blob_sizes.lbs_cred);
>> pr_info("LSM: file blob size = %d\n", blob_sizes.lbs_file);
>> + pr_info("LSM: inode blob size = %d\n", blob_sizes.lbs_inode);
>> pr_info("LSM: task blob size = %d\n", blob_sizes.lbs_task);
>> -#endif
>> +#endif /* CONFIG_SECURITY_LSM_DEBUG */
>>
>> return 0;
>> }
>> @@ -285,6 +291,13 @@ void __init security_add_blobs(struct lsm_blob_sizes
>> *needed)
>> lsm_set_size(&needed->lbs_cred, &blob_sizes.lbs_cred);
>> lsm_set_size(&needed->lbs_file, &blob_sizes.lbs_file);
>> lsm_set_size(&needed->lbs_task, &blob_sizes.lbs_task);
>> + /*
>> + * The inode blob gets an rcu_head in addition to
>> + * what the modules might need.
>> + */
>> + if (needed->lbs_inode && blob_sizes.lbs_inode == 0)
>> + blob_sizes.lbs_inode = sizeof(struct rcu_head);
>> + lsm_set_size(&needed->lbs_inode, &blob_sizes.lbs_inode);
>> }
>>
>> /**
>> @@ -348,6 +361,46 @@ void lsm_early_task(struct task_struct *task)
>> panic("%s: Early task alloc failed.\n", __func__);
>> }
>>
>> +/**
>> + * lsm_inode_alloc - allocate a composite inode blob
>> + * @inode: the inode that needs a blob
>> + *
>> + * Allocate the inode blob for all the modules
>> + *
>> + * Returns 0, or -ENOMEM if memory can't be allocated.
>> + */
>> +int lsm_inode_alloc(struct inode *inode)
>> +{
>> + if (!lsm_inode_cache) {
>> + inode->i_security = NULL;
>> + return 0;
>> + }
>> +
>> + inode->i_security = kmem_cache_zalloc(lsm_inode_cache, GFP_KERNEL);
> Should be GFP_NOFS (and was that way in SELinux and Smack).
Yes, you're correct. I'll make the change.
