integrity-v6.18

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Merge tag 'integrity-v6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:
 "Just a couple of changes: crypto code cleanup and a IMA xattr bug fix"

* tag 'integrity-v6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: don't clear IMA_DIGSIG flag when setting or removing non-IMA xattr
  lib/digsig: Use SHA-1 library instead of crypto_shash
  integrity: Select CRYPTO from INTEGRITY_ASYMMETRIC_KEYS

lib/Kconfig

@@ -477,8 +477,7 @@ config MPILIB
 config SIGNATURE
 	tristate
 	depends on KEYS
-	select CRYPTO
+	select CRYPTO_LIB_SHA1
-	select CRYPTO_SHA1
 	select MPILIB
 	help
 	  Digital signature verification. Currently only RSA is supported.

lib/digsig.c

@@ -18,15 +18,11 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/key.h>
-#include <linux/crypto.h>
-#include <crypto/hash.h>
 #include <crypto/sha1.h>
 #include <keys/user-type.h>
 #include <linux/mpi.h>
 #include <linux/digsig.h>
 
-static struct crypto_shash *shash;
-
 static const char *pkcs_1_v1_5_decode_emsa(const unsigned char *msg,
 						unsigned long  msglen,
 						unsigned long  modulus_bitlen,
@@ -198,12 +194,12 @@ err1:
 int digsig_verify(struct key *keyring, const char *sig, int siglen,
 						const char *data, int datalen)
 {
-	int err = -ENOMEM;
 	struct signature_hdr *sh = (struct signature_hdr *)sig;
-	struct shash_desc *desc = NULL;
+	struct sha1_ctx ctx;
 	unsigned char hash[SHA1_DIGEST_SIZE];
 	struct key *key;
 	char name[20];
+	int err;
 
 	if (siglen < sizeof(*sh) + 2)
 		return -EINVAL;
@@ -230,49 +226,19 @@ int digsig_verify(struct key *keyring, const char *sig, int siglen,
 		return PTR_ERR(key);
 	}
 
-	desc = kzalloc(sizeof(*desc) + crypto_shash_descsize(shash),
+	sha1_init(&ctx);
-		       GFP_KERNEL);
+	sha1_update(&ctx, data, datalen);
-	if (!desc)
+	sha1_update(&ctx, sig, sizeof(*sh));
-		goto err;
+	sha1_final(&ctx, hash);
-
-	desc->tfm = shash;
-
-	crypto_shash_init(desc);
-	crypto_shash_update(desc, data, datalen);
-	crypto_shash_update(desc, sig, sizeof(*sh));
-	crypto_shash_final(desc, hash);
-
-	kfree(desc);
 
 	/* pass signature mpis address */
 	err = digsig_verify_rsa(key, sig + sizeof(*sh), siglen - sizeof(*sh),
 			     hash, sizeof(hash));
 
-err:
 	key_put(key);
 
 	return err ? -EINVAL : 0;
 }
 EXPORT_SYMBOL_GPL(digsig_verify);
 
-static int __init digsig_init(void)
-{
-	shash = crypto_alloc_shash("sha1", 0, 0);
-	if (IS_ERR(shash)) {
-		pr_err("shash allocation failed\n");
-		return  PTR_ERR(shash);
-	}
-
-	return 0;
-
-}
-
-static void __exit digsig_cleanup(void)
-{
-	crypto_free_shash(shash);
-}
-
-module_init(digsig_init);
-module_exit(digsig_cleanup);
-
 MODULE_LICENSE("GPL");

security/integrity/Kconfig

@@ -36,6 +36,7 @@ config INTEGRITY_ASYMMETRIC_KEYS
 	default n
 	select ASYMMETRIC_KEY_TYPE
 	select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+	select CRYPTO
 	select CRYPTO_RSA
 	select X509_CERTIFICATE_PARSER
 	help

security/integrity/ima/ima_appraise.c

@@ -694,6 +694,15 @@ static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name,
 	return 0;
 }
 
+/*
+ * ima_reset_appraise_flags - reset ima_iint_cache flags
+ *
+ * @digsig: whether to clear/set IMA_DIGSIG flag, tristate values
+ *          0: clear IMA_DIGSIG
+ *          1: set IMA_DIGSIG
+ *         -1: don't change IMA_DIGSIG
+ *
+ */
 static void ima_reset_appraise_flags(struct inode *inode, int digsig)
 {
 	struct ima_iint_cache *iint;
@@ -706,9 +715,9 @@ static void ima_reset_appraise_flags(struct inode *inode, int digsig)
 		return;
 	iint->measured_pcrs = 0;
 	set_bit(IMA_CHANGE_XATTR, &iint->atomic_flags);
-	if (digsig)
+	if (digsig == 1)
 		set_bit(IMA_DIGSIG, &iint->atomic_flags);
-	else
+	else if (digsig == 0)
 		clear_bit(IMA_DIGSIG, &iint->atomic_flags);
 }
 
@@ -794,6 +803,8 @@ static int ima_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG);
 	} else if (!strcmp(xattr_name, XATTR_NAME_EVM) && xattr_value_len > 0) {
 		digsig = (xvalue->type == EVM_XATTR_PORTABLE_DIGSIG);
+	} else {
+		digsig = -1;
 	}
 	if (result == 1 || evm_revalidate_status(xattr_name)) {
 		ima_reset_appraise_flags(d_backing_inode(dentry), digsig);
@@ -807,7 +818,7 @@ static int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 			     const char *acl_name, struct posix_acl *kacl)
 {
 	if (evm_revalidate_status(acl_name))
-		ima_reset_appraise_flags(d_backing_inode(dentry), 0);
+		ima_reset_appraise_flags(d_backing_inode(dentry), -1);
 
 	return 0;
 }
@@ -815,11 +826,13 @@ static int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 static int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
 				 const char *xattr_name)
 {
-	int result;
+	int result, digsig = -1;
 
 	result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
 	if (result == 1 || evm_revalidate_status(xattr_name)) {
-		ima_reset_appraise_flags(d_backing_inode(dentry), 0);
+		if (!strcmp(xattr_name, XATTR_NAME_IMA))
+			digsig = 0;
+		ima_reset_appraise_flags(d_backing_inode(dentry), digsig);
 		if (result == 1)
 			result = 0;
 	}