Commit 32538047 authored by Stefan Berger's avatar Stefan Berger Committed by Mimi Zohar
Browse files

security: allow finer granularity in permitting copy-up of security xattrs 



Copying up xattrs is solely based on the security xattr name. For finer
granularity add a dentry parameter to the security_inode_copy_up_xattr
hook definition, allowing decisions to be based on the xattr content as
well.

Co-developed-by: default avatarMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: default avatarStefan Berger <stefanb@linux.ibm.com>
Acked-by: default avatarAmir Goldstein <amir73il@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com> (LSM,SELinux)
Signed-off-by: default avatarMimi Zohar <zohar@linux.ibm.com>
parent c21632b6

fs/overlayfs/copy_up.c

+1 −1
Original line number Diff line number Diff line
@@ -114,7 +114,7 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct de 
		if (ovl_is_private_xattr(sb, name))

			continue;



		error = security_inode_copy_up_xattr(name);

		error = security_inode_copy_up_xattr(old, name);

		if (error < 0 && error != -EOPNOTSUPP)

			break;

		if (error == 1) {

include/linux/lsm_hook_defs.h

+2 −1
Original line number Diff line number Diff line
@@ -176,7 +176,8 @@ LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char *buffer, 
	 size_t buffer_size)

LSM_HOOK(void, LSM_RET_VOID, inode_getsecid, struct inode *inode, u32 *secid)

LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new)

LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, const char *name)

LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, struct dentry *src,

	 const char *name)

LSM_HOOK(int, 0, kernfs_init_security, struct kernfs_node *kn_dir,

	 struct kernfs_node *kn)

LSM_HOOK(int, 0, file_permission, struct file *file, int mask)

include/linux/security.h

+2 −2
Original line number Diff line number Diff line
@@ -398,7 +398,7 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void 
int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);

void security_inode_getsecid(struct inode *inode, u32 *secid);

int security_inode_copy_up(struct dentry *src, struct cred **new);

int security_inode_copy_up_xattr(const char *name);

int security_inode_copy_up_xattr(struct dentry *src, const char *name);

int security_kernfs_init_security(struct kernfs_node *kn_dir,

				  struct kernfs_node *kn);

int security_file_permission(struct file *file, int mask);
@@ -1016,7 +1016,7 @@ static inline int security_kernfs_init_security(struct kernfs_node *kn_dir, 
	return 0;

}



static inline int security_inode_copy_up_xattr(const char *name)

static inline int security_inode_copy_up_xattr(struct dentry *src, const char *name)

{

	return -EOPNOTSUPP;

}

security/integrity/evm/evm_main.c

+1 −1
Original line number Diff line number Diff line
@@ -946,7 +946,7 @@ static void evm_inode_post_setattr(struct mnt_idmap *idmap, 
		evm_update_evmxattr(dentry, NULL, NULL, 0);

}



static int evm_inode_copy_up_xattr(const char *name)

static int evm_inode_copy_up_xattr(struct dentry *src, const char *name)

{

	if (strcmp(name, XATTR_NAME_EVM) == 0)

		return 1; /* Discard */

security/security.c

+3 −2
Original line number Diff line number Diff line
@@ -2628,6 +2628,7 @@ EXPORT_SYMBOL(security_inode_copy_up); 


/**

 * security_inode_copy_up_xattr() - Filter xattrs in an overlayfs copy-up op

 * @src: union dentry of copy-up file

 * @name: xattr name

 *

 * Filter the xattrs being copied up when a unioned file is copied up from a
@@ -2638,7 +2639,7 @@ EXPORT_SYMBOL(security_inode_copy_up); 
 *         if the security module does not know about attribute, or a negative

 *         error code to abort the copy up.

 */

int security_inode_copy_up_xattr(const char *name)

int security_inode_copy_up_xattr(struct dentry *src, const char *name)

{

	int rc;
@@ -2647,7 +2648,7 @@ int security_inode_copy_up_xattr(const char *name) 
	 * xattr), -EOPNOTSUPP if it does not know anything about the xattr or

	 * any other error code in case of an error.

	 */

	rc = call_int_hook(inode_copy_up_xattr, name);

	rc = call_int_hook(inode_copy_up_xattr, src, name);

	if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr))

		return rc;