From: Roberto Sassu <[email protected]>
Commit 8e5d9f916a96 ("smack: deduplicate xattr setting in
smack_inode_init_security()") introduced xattr_dupval() to simplify setting
the xattrs to be provided by the SMACK LSM on inode creation, in the
smack_inode_init_security().
Unfortunately, moving lsm_get_xattr_slot() caused the SMACK64TRANSMUTE
xattr be added in the array of new xattrs before SMACK64. This causes the
HMAC of xattrs calculated by evm_init_hmac() for new files to diverge from
the one calculated by both evm_calc_hmac_or_hash() and evmctl.
evm_init_hmac() calculates the HMAC of the xattrs of new files based on the
order LSMs provide them, while evm_calc_hmac_or_hash() and evmctl calculate
the HMAC based on an ordered xattrs list.
Fix the issue by making evm_init_hmac() calculate the HMAC of new files
based on the ordered xattrs list too.
Fixes: 8e5d9f916a96 ("smack: deduplicate xattr setting in
smack_inode_init_security()")
Signed-off-by: Roberto Sassu <[email protected]>
---
security/integrity/evm/evm_crypto.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/security/integrity/evm/evm_crypto.c
b/security/integrity/evm/evm_crypto.c
index a5e730ffda57..5a8cef45bacf 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -401,6 +401,7 @@ int evm_init_hmac(struct inode *inode, const struct xattr
*xattrs,
{
struct shash_desc *desc;
const struct xattr *xattr;
+ struct xattr_list *xattr_entry;
desc = init_desc(EVM_XATTR_HMAC, HASH_ALGO_SHA1);
if (IS_ERR(desc)) {
@@ -408,11 +409,16 @@ int evm_init_hmac(struct inode *inode, const struct xattr
*xattrs,
return PTR_ERR(desc);
}
- for (xattr = xattrs; xattr->name; xattr++) {
- if (!evm_protected_xattr(xattr->name))
- continue;
+ list_for_each_entry_lockless(xattr_entry, &evm_config_xattrnames,
+ list) {
+ for (xattr = xattrs; xattr->name; xattr++) {
+ if (strcmp(xattr_entry->name +
+ XATTR_SECURITY_PREFIX_LEN, xattr->name) != 0)
+ continue;
- crypto_shash_update(desc, xattr->value, xattr->value_len);
+ crypto_shash_update(desc, xattr->value,
+ xattr->value_len);
+ }
}
hmac_add_misc(desc, inode, EVM_XATTR_HMAC, hmac_val);
--
2.43.0
