From 40ca4ee3136d2d09977d1cab8c0c0e1582c3359d Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Tue, 12 Dec 2023 06:12:43 -0500 Subject: evm: don't copy up 'security.evm' xattr The security.evm HMAC and the original file signatures contain filesystem specific data. As a result, the HMAC and signature are not the same on the stacked and backing filesystems. Don't copy up 'security.evm'. Reviewed-by: Amir Goldstein Reviewed-by: Christian Brauner Signed-off-by: Mimi Zohar --- security/integrity/evm/evm_main.c | 7 +++++++ security/security.c | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-) (limited to 'security') diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 894570fe39bc5..02adba635b02c 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -863,6 +863,13 @@ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) evm_update_evmxattr(dentry, NULL, NULL, 0); } +int evm_inode_copy_up_xattr(const char *name) +{ + if (strcmp(name, XATTR_NAME_EVM) == 0) + return 1; /* Discard */ + return -EOPNOTSUPP; +} + /* * evm_inode_init_security - initializes security.evm HMAC value */ diff --git a/security/security.c b/security/security.c index dcb3e7014f9bd..f00ec4d988b89 100644 --- a/security/security.c +++ b/security/security.c @@ -2539,7 +2539,7 @@ int security_inode_copy_up_xattr(const char *name) return rc; } - return LSM_RET_DEFAULT(inode_copy_up_xattr); + return evm_inode_copy_up_xattr(name); } EXPORT_SYMBOL(security_inode_copy_up_xattr); -- cgit 1.2.3-korg