Both the EVM HMAC and signature xattr formats are file system
specific and can not be copied from one filesystem to another.
EVM differentiates files without any xattrs (INTEGRITY_UNKNOWN)
from those having protected xattrs (INTEGRITY_NOLABEL). This
patch treats the rootfs filesystem as a special case, returning
INTEGRITY_UNKNOWN.
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
---
security/integrity/evm/evm_main.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index f589c9a0..9140016 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -19,6 +19,7 @@
#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/audit.h>
+#include <linux/magic.h>
#include <linux/xattr.h>
#include <linux/integrity.h>
#include <linux/evm.h>
@@ -128,11 +129,16 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
if (rc <= 0) {
evm_status = INTEGRITY_FAIL;
if (rc == -ENODATA) {
+ struct super_block *sb = dentry->d_inode->i_sb;
+
rc = evm_find_protected_xattrs(dentry);
- if (rc > 0)
- evm_status = INTEGRITY_NOLABEL;
- else if (rc == 0)
+ if (rc == 0)
evm_status = INTEGRITY_NOXATTRS; /* new file */
+ else if (rc > 0 && sb->s_magic == TMPFS_MAGIC
+ && strcmp(sb->s_id, "rootfs") == 0)
+ evm_status = INTEGRITY_UNKNOWN;
+ else if (rc > 0)
+ evm_status = INTEGRITY_NOLABEL;
} else if (rc == -EOPNOTSUPP) {
evm_status = INTEGRITY_UNKNOWN;
}
--
1.8.1.4
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