Re: [PATCH v4 5/20] lsm: Refactor return value of LSM hook inode_copy_up_xattr
From: Paul Moore <paul@paul-moore.com>
Date: 2024-07-19 02:08:05
Also in:
bpf, linux-integrity, linux-kselftest, linux-security-module, selinux
On Jul 11, 2024 Xu Kuohai [off-list ref] wrote:
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(-)
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quoted hunk ↗ jump to hunk
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. */
Updating the comment here is good, but considering that we also discuss the return value in the function header comment, I think it might be better to just remove this comment entirely and leave the function header comment as the single source. Duplicated comments/docs tend to fall out of sync and create confusion.
rc = call_int_hook(inode_copy_up_xattr, src, name); if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr))
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