From 3dcbad52cf18c3c379e96b992d22815439ebbe53 Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Tue, 2 Sep 2014 16:31:43 +0300 Subject: [PATCH] evm: properly handle INTEGRITY_NOXATTRS EVM status Unless an LSM labels a file during d_instantiate(), newly created files are not labeled with an initial security.evm xattr, until the file closes. EVM, before allowing a protected, security xattr to be written, verifies the existing 'security.evm' value is good. For newly created files without a security.evm label, this verification prevents writing any protected, security xattrs, until the file closes. Following is the example when this happens: fd = open("foo", O_CREAT | O_WRONLY, 0644); setxattr("foo", "security.SMACK64", value, sizeof(value), 0); close(fd); While INTEGRITY_NOXATTRS status is handled in other places, such as evm_inode_setattr(), it does not handle it in all cases in evm_protect_xattr(). By limiting the use of INTEGRITY_NOXATTRS to newly created files, we can now allow setting "protected" xattrs. Changelog: - limit the use of INTEGRITY_NOXATTRS to IMA identified new files Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar Cc: 3.14+ --- security/integrity/evm/evm_main.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 40220124364c..9685af330de5 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -285,6 +285,13 @@ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, goto out; } evm_status = evm_verify_current_integrity(dentry); + if (evm_status == INTEGRITY_NOXATTRS) { + struct integrity_iint_cache *iint; + + iint = integrity_iint_find(dentry->d_inode); + if (iint && (iint->flags & IMA_NEW_FILE)) + return 0; + } out: if (evm_status != INTEGRITY_PASS) integrity_audit_msg(AUDIT_INTEGRITY_METADATA, dentry->d_inode, -- GitLab