Commit e1ca7129 authored by Casey Schaufler's avatar Casey Schaufler Committed by Paul Moore
Browse files

LSM: Helpers for attribute names and filling lsm_ctx 



Add lsm_name_to_attr(), which translates a text string to a
LSM_ATTR value if one is available.

Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
the trailing attribute value.

Both are used in module specific components of LSM system calls.

Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
Reviewed-by: default avatarJohn Johansen <john.johansen@canonical.com>
Reviewed-by: default avatarSerge Hallyn <serge@hallyn.com>
Reviewed-by: default avatarMickaël Salaün <mic@digikod.net>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 5f423759

include/linux/security.h

+14 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#include <linux/string.h>

#include <linux/mm.h>

#include <linux/sockptr.h>

#include <uapi/linux/lsm.h>



struct linux_binprm;

struct cred;
@@ -264,6 +265,7 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb); 
/* prototypes */

extern int security_init(void);

extern int early_security_init(void);

extern u64 lsm_name_to_attr(const char *name);



/* Security operations */

int security_binder_set_context_mgr(const struct cred *mgr);
@@ -490,6 +492,8 @@ int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen); 
int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);

int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);

int security_locked_down(enum lockdown_reason what);

int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,

		      size_t context_size, u64 id, u64 flags);

#else /* CONFIG_SECURITY */



static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
@@ -507,6 +511,11 @@ static inline int unregister_blocking_lsm_notifier(struct notifier_block *nb) 
	return 0;

}



static inline u64 lsm_name_to_attr(const char *name)

{

	return LSM_ATTR_UNDEF;

}



static inline void security_free_mnt_opts(void **mnt_opts)

{

}
@@ -1415,6 +1424,11 @@ static inline int security_locked_down(enum lockdown_reason what) 
{

	return 0;

}

static inline int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,

				    size_t context_size, u64 id, u64 flags)

{

	return -EOPNOTSUPP;

}

#endif	/* CONFIG_SECURITY */



#if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)

security/lsm_syscalls.c

+24 −0
Original line number Diff line number Diff line
@@ -17,6 +17,30 @@ 
#include <linux/lsm_hooks.h>

#include <uapi/linux/lsm.h>



/**

 * lsm_name_to_attr - map an LSM attribute name to its ID

 * @name: name of the attribute

 *

 * Returns the LSM attribute value associated with @name, or 0 if

 * there is no mapping.

 */

u64 lsm_name_to_attr(const char *name)

{

	if (!strcmp(name, "current"))

		return LSM_ATTR_CURRENT;

	if (!strcmp(name, "exec"))

		return LSM_ATTR_EXEC;

	if (!strcmp(name, "fscreate"))

		return LSM_ATTR_FSCREATE;

	if (!strcmp(name, "keycreate"))

		return LSM_ATTR_KEYCREATE;

	if (!strcmp(name, "prev"))

		return LSM_ATTR_PREV;

	if (!strcmp(name, "sockcreate"))

		return LSM_ATTR_SOCKCREATE;

	return LSM_ATTR_UNDEF;

}



/**

 * sys_lsm_set_self_attr - Set current task's security module attribute

 * @attr: which attribute to set

security/security.c

+41 −0
Original line number Diff line number Diff line
@@ -771,6 +771,47 @@ static int lsm_superblock_alloc(struct super_block *sb) 
	return 0;

}



/**

 * lsm_fill_user_ctx - Fill a user space lsm_ctx structure

 * @ctx: an LSM context to be filled

 * @context: the new context value

 * @context_size: the size of the new context value

 * @id: LSM id

 * @flags: LSM defined flags

 *

 * Fill all of the fields in a user space lsm_ctx structure.

 * Caller is assumed to have verified that @ctx has enough space

 * for @context.

 *

 * Returns 0 on success, -EFAULT on a copyout error, -ENOMEM

 * if memory can't be allocated.

 */

int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,

		      size_t context_size, u64 id, u64 flags)

{

	struct lsm_ctx *lctx;

	size_t locallen = struct_size(lctx, ctx, context_size);

	int rc = 0;



	lctx = kzalloc(locallen, GFP_KERNEL);

	if (lctx == NULL)

		return -ENOMEM;



	lctx->id = id;

	lctx->flags = flags;

	lctx->ctx_len = context_size;

	lctx->len = locallen;



	memcpy(lctx->ctx, context, context_size);



	if (copy_to_user(ctx, lctx, locallen))

		rc = -EFAULT;



	kfree(lctx);



	return rc;

}



/*

 * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and

 * can be accessed with: