[PATCH bpf-next v4 05/20] lsm: Refactor return value of LSM hook inode_copy_up_xattr
From: Xu Kuohai <xukuohai@huaweicloud.com>
Date: 2024-07-11 11:14:00
Also in:
bpf, linux-integrity, linux-kselftest, linux-security-module, selinux
Subsystem:
extended verification module (evm), filesystems (vfs and infrastructure), integrity measurement architecture (ima), overlay filesystem, security subsystem, selinux security module, smack security module, the rest · Maintainers:
Mimi Zohar, Roberto Sassu, Alexander Viro, Christian Brauner, Dmitry Kasatkin, Miklos Szeredi, Amir Goldstein, Paul Moore, James Morris, "Serge E. Hallyn", Stephen Smalley, Casey Schaufler, Linus Torvalds
From: Xu Kuohai <redacted> To be consistent with most LSM hooks, convert the return value of hook inode_copy_up_xattr to 0 or a negative error code. Before: - Hook inode_copy_up_xattr returns 0 when accepting xattr, 1 when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. After: - Hook inode_copy_up_xattr returns 0 when accepting xattr, *-ECANCELED* when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. Signed-off-by: Xu Kuohai <redacted> --- fs/overlayfs/copy_up.c | 6 +++--- security/integrity/evm/evm_main.c | 2 +- security/security.c | 12 ++++++------ security/selinux/hooks.c | 4 ++-- security/smack/smack_lsm.c | 6 +++--- 5 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index a5ef2005a2cc..337a5be99ac9 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c@@ -115,12 +115,12 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct de continue; error = security_inode_copy_up_xattr(old, name); - if (error < 0 && error != -EOPNOTSUPP) - break; - if (error == 1) { + if (error == -ECANCELED) { error = 0; continue; /* Discard */ } + if (error < 0 && error != -EOPNOTSUPP) + break; if (is_posix_acl_xattr(name)) { error = ovl_copy_acl(OVL_FS(sb), oldpath, new, name);
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 62fe66dd53ce..6924ed508ebd 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c@@ -1000,7 +1000,7 @@ static int evm_inode_copy_up_xattr(struct dentry *src, const char *name) case EVM_XATTR_HMAC: case EVM_IMA_XATTR_DIGSIG: default: - rc = 1; /* discard */ + rc = -ECANCELED; /* discard */ } kfree(xattr_data);
diff --git a/security/security.c b/security/security.c
index 26eea8f4cd74..12215ca286af 100644
--- a/security/security.c
+++ b/security/security.c@@ -2675,18 +2675,18 @@ EXPORT_SYMBOL(security_inode_copy_up); * lower layer to the union/overlay layer. The caller is responsible for * reading and writing the xattrs, this hook is merely a filter. * - * Return: Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP - * if the security module does not know about attribute, or a negative - * error code to abort the copy up. + * Return: Returns 0 to accept the xattr, -ECANCELED to discard the xattr, + * -EOPNOTSUPP 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(struct dentry *src, const char *name) { int rc; /* - * The implementation can return 0 (accept the xattr), 1 (discard the - * xattr), -EOPNOTSUPP if it does not know anything about the xattr or - * any other error code in case of an error. + * The implementation can return 0 (accept the xattr), -ECANCELED + * (discard the 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, src, name); if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr))
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 5dedd3917d57..f9a6637dfd78 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c@@ -3528,8 +3528,8 @@ static int selinux_inode_copy_up_xattr(struct dentry *dentry, const char *name) * xattrs up. Instead, filter out SELinux-related xattrs following * policy load. */ - if (selinux_initialized() && strcmp(name, XATTR_NAME_SELINUX) == 0) - return 1; /* Discard */ + if (selinux_initialized() && !strcmp(name, XATTR_NAME_SELINUX)) + return -ECANCELED; /* Discard */ /* * Any other attribute apart from SELINUX is not claimed, supported * by selinux.
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6f73906bf7ea..ae8f1c2d0ca6 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c@@ -4893,10 +4893,10 @@ static int smack_inode_copy_up(struct dentry *dentry, struct cred **new) static int smack_inode_copy_up_xattr(struct dentry *src, const char *name) { /* - * Return 1 if this is the smack access Smack attribute. + * Return -ECANCELED if this is the smack access Smack attribute. */ - if (strcmp(name, XATTR_NAME_SMACK) == 0) - return 1; + if (!strcmp(name, XATTR_NAME_SMACK)) + return -ECANCELED; return -EOPNOTSUPP; }
--
2.30.2