Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull integrity updates from James Morris:
 "This adds support for EVM signatures based on larger digests, contains
  a new audit record AUDIT_INTEGRITY_POLICY_RULE to differentiate the
  IMA policy rules from the IMA-audit messages, addresses two deadlocks
  due to either loading or searching for crypto algorithms, and cleans
  up the audit messages"

* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  EVM: fix return value check in evm_write_xattrs()
  integrity: prevent deadlock during digsig verification.
  evm: Allow non-SHA1 digital signatures
  evm: Don't deadlock if a crypto algorithm is unavailable
  integrity: silence warning when CONFIG_SECURITYFS is not enabled
  ima: Differentiate auditing policy rules from "audit" actions
  ima: Do not audit if CONFIG_INTEGRITY_AUDIT is not set
  ima: Use audit_log_format() rather than audit_log_string()
  ima: Call audit_log_string() rather than logging it untrusted

12 files changed, 108 insertions, 46 deletions

diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
index ab6a029062a1..6dc075144508 100644
--- a/security/integrity/digsig_asymmetric.c
+++ b/security/integrity/digsig_asymmetric.c
@@ -115,3 +115,26 @@ int asymmetric_verify(struct key *keyring, const char *sig,
         pr_debug("%s() = %d\n", __func__, ret);
         return ret;
 }
+
+/**
+ * integrity_kernel_module_request - prevent crypto-pkcs1pad(rsa,*) requests
+ * @kmod_name: kernel module name
+ *
+ * We have situation, when public_key_verify_signature() in case of RSA
+ * algorithm use alg_name to store internal information in order to
+ * construct an algorithm on the fly, but crypto_larval_lookup() will try
+ * to use alg_name in order to load kernel module with same name.
+ * Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules,
+ * we are safe to fail such module request from crypto_larval_lookup().
+ *
+ * In this way we prevent modprobe execution during digsig verification
+ * and avoid possible deadlock if modprobe and/or it's dependencies
+ * also signed with digsig.
+ */
+int integrity_kernel_module_request(char *kmod_name)
+{
+        if (strncmp(kmod_name, "crypto-pkcs1pad(rsa,", 20) == 0)
+                return -EINVAL;
+
+        return 0;
+}
diff --git a/security/integrity/evm/Kconfig b/security/integrity/evm/Kconfig
index d593346d0bba..60221852b26a 100644
--- a/security/integrity/evm/Kconfig
+++ b/security/integrity/evm/Kconfig
@@ -4,6 +4,7 @@ config EVM
         select ENCRYPTED_KEYS
         select CRYPTO_HMAC
         select CRYPTO_SHA1
+        select CRYPTO_HASH_INFO
         default n
         help
           EVM protects a file's security extended attributes against
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h
index 1257c3c24723..c3f437f5db10 100644
--- a/security/integrity/evm/evm.h
+++ b/security/integrity/evm/evm.h
@@ -47,6 +47,11 @@ extern struct crypto_shash *hash_tfm;
 /* List of EVM protected security xattrs */
 extern struct list_head evm_config_xattrnames;
 
+struct evm_digest {
+        struct ima_digest_data hdr;
+        char digest[IMA_MAX_DIGEST_SIZE];
+} __packed;
+
 int evm_init_key(void);
 int evm_update_evmxattr(struct dentry *dentry,
                         const char *req_xattr_name,
@@ -54,10 +59,11 @@ int evm_update_evmxattr(struct dentry *dentry,
                         size_t req_xattr_value_len);
 int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
                   const char *req_xattr_value,
-                  size_t req_xattr_value_len, char *digest);
+                  size_t req_xattr_value_len, struct evm_digest *data);
 int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name,
                   const char *req_xattr_value,
-                  size_t req_xattr_value_len, char type, char *digest);
+                  size_t req_xattr_value_len, char type,
+                  struct evm_digest *data);
 int evm_init_hmac(struct inode *inode, const struct xattr *xattr,
                   char *hmac_val);
 int evm_init_secfs(void);
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index b60524310855..8a3905bb02c7 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -21,6 +21,7 @@
 #include <linux/evm.h>
 #include <keys/encrypted-type.h>
 #include <crypto/hash.h>
+#include <crypto/hash_info.h>
 #include "evm.h"
 
 #define EVMKEY "evm-key"
@@ -29,7 +30,7 @@ static unsigned char evmkey[MAX_KEY_SIZE];
 static int evmkey_len = MAX_KEY_SIZE;
 
 struct crypto_shash *hmac_tfm;
-struct crypto_shash *hash_tfm;
+static struct crypto_shash *evm_tfm[HASH_ALGO__LAST];
 
 static DEFINE_MUTEX(mutex);
 
@@ -38,7 +39,6 @@ static DEFINE_MUTEX(mutex);
 static unsigned long evm_set_key_flags;
 
 static char * const evm_hmac = "hmac(sha1)";
-static char * const evm_hash = "sha1";
 
 /**
  * evm_set_key() - set EVM HMAC key from the kernel
@@ -74,10 +74,10 @@ busy:
 }
 EXPORT_SYMBOL_GPL(evm_set_key);
 
-static struct shash_desc *init_desc(char type)
+static struct shash_desc *init_desc(char type, uint8_t hash_algo)
 {
         long rc;
-        char *algo;
+        const char *algo;
         struct crypto_shash **tfm;
         struct shash_desc *desc;
 
@@ -89,15 +89,16 @@ static struct shash_desc *init_desc(char type)
                 tfm = &hmac_tfm;
                 algo = evm_hmac;
         } else {
-                tfm = &hash_tfm;
-                algo = evm_hash;
+                tfm = &evm_tfm[hash_algo];
+                algo = hash_algo_name[hash_algo];
         }
 
         if (*tfm == NULL) {
                 mutex_lock(&mutex);
                 if (*tfm)
                         goto out;
-                *tfm = crypto_alloc_shash(algo, 0, CRYPTO_ALG_ASYNC);
+                *tfm = crypto_alloc_shash(algo, 0,
+                                          CRYPTO_ALG_ASYNC | CRYPTO_NOLOAD);
                 if (IS_ERR(*tfm)) {
                         rc = PTR_ERR(*tfm);
                         pr_err("Can not allocate %s (reason: %ld)\n", algo, rc);
@@ -186,10 +187,10 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
  * each xattr, but attempt to re-use the previously allocated memory.
  */
 static int evm_calc_hmac_or_hash(struct dentry *dentry,
-                                const char *req_xattr_name,
-                                const char *req_xattr_value,
-                                size_t req_xattr_value_len,
-                                char type, char *digest)
+                                 const char *req_xattr_name,
+                                 const char *req_xattr_value,
+                                 size_t req_xattr_value_len,
+                                 uint8_t type, struct evm_digest *data)
 {
         struct inode *inode = d_backing_inode(dentry);
         struct xattr_list *xattr;
@@ -204,10 +205,12 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
             inode->i_sb->s_user_ns != &init_user_ns)
                 return -EOPNOTSUPP;
 
-        desc = init_desc(type);
+        desc = init_desc(type, data->hdr.algo);
         if (IS_ERR(desc))
                 return PTR_ERR(desc);
 
+        data->hdr.length = crypto_shash_digestsize(desc->tfm);
+
         error = -ENODATA;
         list_for_each_entry_rcu(xattr, &evm_config_xattrnames, list) {
                 bool is_ima = false;
@@ -239,7 +242,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
                 if (is_ima)
                         ima_present = true;
         }
-        hmac_add_misc(desc, inode, type, digest);
+        hmac_add_misc(desc, inode, type, data->digest);
 
         /* Portable EVM signatures must include an IMA hash */
         if (type == EVM_XATTR_PORTABLE_DIGSIG && !ima_present)
@@ -252,18 +255,18 @@ out:
 
 int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
                   const char *req_xattr_value, size_t req_xattr_value_len,
-                  char *digest)
+                  struct evm_digest *data)
 {
         return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
-                               req_xattr_value_len, EVM_XATTR_HMAC, digest);
+                                    req_xattr_value_len, EVM_XATTR_HMAC, data);
 }
 
 int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name,
                   const char *req_xattr_value, size_t req_xattr_value_len,
-                  char type, char *digest)
+                  char type, struct evm_digest *data)
 {
         return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
-                                     req_xattr_value_len, type, digest);
+                                     req_xattr_value_len, type, data);
 }
 
 static int evm_is_immutable(struct dentry *dentry, struct inode *inode)
@@ -303,7 +306,7 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name,
                         const char *xattr_value, size_t xattr_value_len)
 {
         struct inode *inode = d_backing_inode(dentry);
-        struct evm_ima_xattr_data xattr_data;
+        struct evm_digest data;
         int rc = 0;
 
         /*
@@ -316,13 +319,14 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name,
         if (rc)
                 return -EPERM;
 
+        data.hdr.algo = HASH_ALGO_SHA1;
         rc = evm_calc_hmac(dentry, xattr_name, xattr_value,
-                           xattr_value_len, xattr_data.digest);
+                           xattr_value_len, &data);
         if (rc == 0) {
-                xattr_data.type = EVM_XATTR_HMAC;
+                data.hdr.xattr.sha1.type = EVM_XATTR_HMAC;
                 rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_EVM,
-                                           &xattr_data,
-                                           sizeof(xattr_data), 0);
+                                           &data.hdr.xattr.data[1],
+                                           SHA1_DIGEST_SIZE + 1, 0);
         } else if (rc == -ENODATA && (inode->i_opflags & IOP_XATTR)) {
                 rc = __vfs_removexattr(dentry, XATTR_NAME_EVM);
         }
@@ -334,7 +338,7 @@ int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr,
 {
         struct shash_desc *desc;
 
-        desc = init_desc(EVM_XATTR_HMAC);
+        desc = init_desc(EVM_XATTR_HMAC, HASH_ALGO_SHA1);
         if (IS_ERR(desc)) {
                 pr_info("init_desc failed\n");
                 return PTR_ERR(desc);
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index f9eff5041e4c..7f3f54d89a6e 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -25,6 +25,7 @@
 #include <linux/magic.h>
 
 #include <crypto/hash.h>
+#include <crypto/hash_info.h>
 #include <crypto/algapi.h>
 #include "evm.h"
 
@@ -134,8 +135,9 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
                                              struct integrity_iint_cache *iint)
 {
         struct evm_ima_xattr_data *xattr_data = NULL;
-        struct evm_ima_xattr_data calc;
+        struct signature_v2_hdr *hdr;
         enum integrity_status evm_status = INTEGRITY_PASS;
+        struct evm_digest digest;
         struct inode *inode;
         int rc, xattr_len;
 
@@ -171,25 +173,28 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
                         evm_status = INTEGRITY_FAIL;
                         goto out;
                 }
+
+                digest.hdr.algo = HASH_ALGO_SHA1;
                 rc = evm_calc_hmac(dentry, xattr_name, xattr_value,
-                                   xattr_value_len, calc.digest);
+                                   xattr_value_len, &digest);
                 if (rc)
                         break;
-                rc = crypto_memneq(xattr_data->digest, calc.digest,
-                            sizeof(calc.digest));
+                rc = crypto_memneq(xattr_data->digest, digest.digest,
+                                   SHA1_DIGEST_SIZE);
                 if (rc)
                         rc = -EINVAL;
                 break;
         case EVM_IMA_XATTR_DIGSIG:
         case EVM_XATTR_PORTABLE_DIGSIG:
+                hdr = (struct signature_v2_hdr *)xattr_data;
+                digest.hdr.algo = hdr->hash_algo;
                 rc = evm_calc_hash(dentry, xattr_name, xattr_value,
-                                   xattr_value_len, xattr_data->type,
-                                   calc.digest);
+                                   xattr_value_len, xattr_data->type, &digest);
                 if (rc)
                         break;
                 rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM,
                                         (const char *)xattr_data, xattr_len,
-                                        calc.digest, sizeof(calc.digest));
+                                        digest.digest, digest.hdr.length);
                 if (!rc) {
                         inode = d_backing_inode(dentry);
 
diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index 637eb999e340..77de71b7794c 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -193,8 +193,8 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf,
                 return -E2BIG;
 
         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_EVM_XATTR);
-        if (IS_ERR(ab))
-                return PTR_ERR(ab);
+        if (!ab)
+                return -ENOMEM;
 
         xattr = kmalloc(sizeof(struct xattr_list), GFP_KERNEL);
         if (!xattr) {
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index 149faa81f6f0..5a6810041e5c 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -219,10 +219,13 @@ static int __init integrity_fs_init(void)
 {
         integrity_dir = securityfs_create_dir("integrity", NULL);
         if (IS_ERR(integrity_dir)) {
-                pr_err("Unable to create integrity sysfs dir: %ld\n",
-                       PTR_ERR(integrity_dir));
+                int ret = PTR_ERR(integrity_dir);
+
+                if (ret != -ENODEV)
+                        pr_err("Unable to create integrity sysfs dir: %d\n",
+                               ret);
                 integrity_dir = NULL;
-                return PTR_ERR(integrity_dir);
+                return ret;
         }
 
         return 0;
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 004919d9bf09..13b446328dda 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -12,6 +12,7 @@ config IMA
         select TCG_TIS if TCG_TPM && X86
         select TCG_CRB if TCG_TPM && ACPI
         select TCG_IBMVTPM if TCG_TPM && PPC_PSERIES
+        select INTEGRITY_AUDIT if AUDIT
         help
           The Trusted Computing Group(TCG) runtime Integrity
           Measurement Architecture(IMA) maintains a list of hash
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 1659abb344f9..8c9499867c91 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -657,14 +657,16 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
                               bool (*rule_operator)(kuid_t, kuid_t))
 {
+        if (!ab)
+                return;
+
         if (rule_operator == &uid_gt)
                 audit_log_format(ab, "%s>", key);
         else if (rule_operator == &uid_lt)
                 audit_log_format(ab, "%s<", key);
         else
                 audit_log_format(ab, "%s=", key);
-        audit_log_untrustedstring(ab, value);
-        audit_log_format(ab, " ");
+        audit_log_format(ab, "%s ", value);
 }
 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 {
@@ -679,7 +681,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
         bool uid_token;
         int result = 0;
 
-        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
+        ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
+                                       AUDIT_INTEGRITY_POLICY_RULE);
 
         entry->uid = INVALID_UID;
         entry->fowner = INVALID_UID;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 0bb372eed62a..e60473b13a8d 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -15,6 +15,7 @@
 #include <linux/integrity.h>
 #include <crypto/sha.h>
 #include <linux/key.h>
+#include <linux/audit.h>
 
 /* iint action cache flags */
 #define IMA_MEASURE             0x00000001
@@ -199,6 +200,13 @@ static inline void evm_load_x509(void)
 void integrity_audit_msg(int audit_msgno, struct inode *inode,
                          const unsigned char *fname, const char *op,
                          const char *cause, int result, int info);
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+        return audit_log_start(ctx, gfp_mask, type);
+}
+
 #else
 static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
                                        const unsigned char *fname,
@@ -206,4 +214,11 @@ static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
                                        int result, int info)
 {
 }
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+        return NULL;
+}
+
 #endif
diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index ab10a25310a1..82c98f7d217e 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -45,11 +45,7 @@ void integrity_audit_msg(int audit_msgno, struct inode *inode,
                          from_kuid(&init_user_ns, audit_get_loginuid(current)),
                          audit_get_sessionid(current));
         audit_log_task_context(ab);
-        audit_log_format(ab, " op=");
-        audit_log_string(ab, op);
-        audit_log_format(ab, " cause=");
-        audit_log_string(ab, cause);
-        audit_log_format(ab, " comm=");
+        audit_log_format(ab, " op=%s cause=%s comm=", op, cause);
         audit_log_untrustedstring(ab, get_task_comm(name, current));
         if (fname) {
                 audit_log_format(ab, " name=");
diff --git a/security/security.c b/security/security.c
index ab4f96347ebb..47cfff01d7ec 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1032,7 +1032,12 @@ int security_kernel_create_files_as(struct cred *new, struct inode *inode)
 
 int security_kernel_module_request(char *kmod_name)
 {
-        return call_int_hook(kernel_module_request, 0, kmod_name);
+        int ret;
+
+        ret = call_int_hook(kernel_module_request, 0, kmod_name);
+        if (ret)
+                return ret;
+        return integrity_kernel_module_request(kmod_name);
 }
 
 int security_kernel_read_file(struct file *file, enum kernel_read_file_id id)