3.16.7-ckt2 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Dmitry Kasatkin <d.kasatkin@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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 9f5f923f7bfd..970772c731ff 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -284,6 +284,13 @@ 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,
--
2.1.0
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