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authorDmitry Kasatkin <d.kasatkin@samsung.com>2014-09-02 16:31:43 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-14 08:59:48 -0800
commitc318c31cd1448461dfd2c82d87865f61ddde2d4c (patch)
tree179f358259dc93747b82ed90f31d51027058d786 /security
parent7f4ec7741d144d51063dcf4ca68978729ab2d63f (diff)
downloadlwn-c318c31cd1448461dfd2c82d87865f61ddde2d4c.tar.gz
lwn-c318c31cd1448461dfd2c82d87865f61ddde2d4c.zip
evm: properly handle INTEGRITY_NOXATTRS EVM status
commit 3dcbad52cf18c3c379e96b992d22815439ebbe53 upstream. 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 <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/evm/evm_main.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 3c5cbb977254..5e9f1d2f0901 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -269,6 +269,13 @@ 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,