LSM: Fix for security_inode_getsecurity and -EOPNOTSUPP (2885c1e3) · Commits · 戴 / test

Serge Hallyn pointed out that the current implementation of security_inode_getsecurity() works if there is only one hook provided for it, but will fail if there is more than one and the attribute requested isn't supplied by the first module. This isn't a problem today, since only SELinux and Smack provide this hook and there is (currently) no way to enable both of those modules at the same time. Serge, however, wants to introduce a capability attribute and an inode_getsecurity hook in the capability security module to handle it. This addresses that upcoming problem, will be required for "extreme stacking" and is just a better implementation. Signed-off-by:

Casey Schaufler <casey@schaufler-ca.com> Acked-by:

Serge Hallyn <serge@hallyn.com> Signed-off-by:

James Morris <james.l.morris@oracle.com>

security/security.c

+25 −4

Original line number	Diff line number	Diff line
		@@ -700,18 +700,39 @@ int security_inode_killpriv(struct dentry *dentry)

		int security_inode_getsecurity(struct inode inode, const char name, void **buffer, bool alloc)
		{
		struct security_hook_list *hp;
		int rc;

		if (unlikely(IS_PRIVATE(inode)))
		return -EOPNOTSUPP;
		return call_int_hook(inode_getsecurity, -EOPNOTSUPP, inode, name,
		buffer, alloc);
		/*
		* Only one module will provide an attribute with a given name.
		*/
		list_for_each_entry(hp, &security_hook_heads.inode_getsecurity, list) {
		rc = hp->hook.inode_getsecurity(inode, name, buffer, alloc);
		if (rc != -EOPNOTSUPP)
		return rc;
		}
		return -EOPNOTSUPP;
		}

		int security_inode_setsecurity(struct inode inode, const char name, const void *value, size_t size, int flags)
		{
		struct security_hook_list *hp;
		int rc;

		if (unlikely(IS_PRIVATE(inode)))
		return -EOPNOTSUPP;
		return call_int_hook(inode_setsecurity, -EOPNOTSUPP, inode, name,
		value, size, flags);
		/*
		* Only one module will provide an attribute with a given name.
		*/
		list_for_each_entry(hp, &security_hook_heads.inode_setsecurity, list) {
		rc = hp->hook.inode_setsecurity(inode, name, value, size,
		flags);
		if (rc != -EOPNOTSUPP)
		return rc;
		}
		return -EOPNOTSUPP;
		}

		int security_inode_listsecurity(struct inode inode, char buffer, size_t buffer_size)

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