Commit 38b323e5 authored by Casey Schaufler's avatar Casey Schaufler Committed by Paul Moore
Browse files

Smack: implement setselfattr and getselfattr hooks 



Implement Smack support for security_[gs]etselfattr.
Refactor the setprocattr hook to avoid code duplication.

Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
Reviewed-by: default avatarJohn Johansen <john.johansen@canonical.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent e1ca7129

security/smack/smack_lsm.c

+90 −5
Original line number Diff line number Diff line
@@ -3626,6 +3626,46 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) 
	return;

}



/**

 * smack_getselfattr - Smack current process attribute

 * @attr: which attribute to fetch

 * @ctx: buffer to receive the result

 * @size: available size in, actual size out

 * @flags: unused

 *

 * Fill the passed user space @ctx with the details of the requested

 * attribute.

 *

 * Returns the number of attributes on success, an error code otherwise.

 * There will only ever be one attribute.

 */

static int smack_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,

			     size_t *size, u32 flags)

{

	struct smack_known *skp = smk_of_current();

	int total;

	int slen;

	int rc;



	if (attr != LSM_ATTR_CURRENT)

		return -EOPNOTSUPP;



	slen = strlen(skp->smk_known) + 1;

	total = ALIGN(slen + sizeof(*ctx), 8);

	if (total > *size)

		rc = -E2BIG;

	else if (ctx)

		rc = lsm_fill_user_ctx(ctx, skp->smk_known, slen, LSM_ID_SMACK,

				       0);

	else

		rc = 1;



	*size = total;

	if (rc >= 0)

		return 1;

	return rc;

}



/**

 * smack_getprocattr - Smack process attribute access

 * @p: the object task
@@ -3655,8 +3695,8 @@ static int smack_getprocattr(struct task_struct *p, const char *name, char **val 
}



/**

 * smack_setprocattr - Smack process attribute setting

 * @name: the name of the attribute in /proc/.../attr

 * do_setattr - Smack process attribute setting

 * @attr: the ID of the attribute

 * @value: the value to set

 * @size: the size of the value

 *
@@ -3665,7 +3705,7 @@ static int smack_getprocattr(struct task_struct *p, const char *name, char **val 
 *

 * Returns the length of the smack label or an error code

 */

static int smack_setprocattr(const char *name, void *value, size_t size)

static int do_setattr(u64 attr, void *value, size_t size)

{

	struct task_smack *tsp = smack_cred(current_cred());

	struct cred *new;
@@ -3679,8 +3719,8 @@ static int smack_setprocattr(const char *name, void *value, size_t size) 
	if (value == NULL || size == 0 || size >= SMK_LONGLABEL)

		return -EINVAL;



	if (strcmp(name, "current") != 0)

		return -EINVAL;

	if (attr != LSM_ATTR_CURRENT)

		return -EOPNOTSUPP;



	skp = smk_import_entry(value, size);

	if (IS_ERR(skp))
@@ -3719,6 +3759,49 @@ static int smack_setprocattr(const char *name, void *value, size_t size) 
	return size;

}



/**

 * smack_setselfattr - Set a Smack process attribute

 * @attr: which attribute to set

 * @ctx: buffer containing the data

 * @size: size of @ctx

 * @flags: unused

 *

 * Fill the passed user space @ctx with the details of the requested

 * attribute.

 *

 * Returns 0 on success, an error code otherwise.

 */

static int smack_setselfattr(unsigned int attr, struct lsm_ctx *ctx,

			     size_t size, u32 flags)

{

	int rc;



	rc = do_setattr(attr, ctx->ctx, ctx->ctx_len);

	if (rc > 0)

		return 0;

	return rc;

}



/**

 * smack_setprocattr - Smack process attribute setting

 * @name: the name of the attribute in /proc/.../attr

 * @value: the value to set

 * @size: the size of the value

 *

 * Sets the Smack value of the task. Only setting self

 * is permitted and only with privilege

 *

 * Returns the length of the smack label or an error code

 */

static int smack_setprocattr(const char *name, void *value, size_t size)

{

	int attr = lsm_name_to_attr(name);



	if (attr != LSM_ATTR_UNDEF)

		return do_setattr(attr, value, size);

	return -EINVAL;

}



/**

 * smack_unix_stream_connect - Smack access on UDS

 * @sock: one sock
@@ -5033,6 +5116,8 @@ static struct security_hook_list smack_hooks[] __ro_after_init = { 


	LSM_HOOK_INIT(d_instantiate, smack_d_instantiate),



	LSM_HOOK_INIT(getselfattr, smack_getselfattr),

	LSM_HOOK_INIT(setselfattr, smack_setselfattr),

	LSM_HOOK_INIT(getprocattr, smack_getprocattr),

	LSM_HOOK_INIT(setprocattr, smack_setprocattr),