1 files changed, 180 insertions, 103 deletions

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index ed3d623724cd..bbb2f5ced988 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -10,10 +10,13 @@
  * Modified by Eric Biggers, 2019 for v2 policy support.
  */
 
+#include <linux/export.h>
+#include <linux/fs_context.h>
+#include <linux/mount.h>
 #include <linux/random.h>
 #include <linux/seq_file.h>
 #include <linux/string.h>
-#include <linux/mount.h>
+
 #include "fscrypt_private.h"
 
 /**
@@ -32,15 +35,41 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
 	return !memcmp(policy1, policy2, fscrypt_policy_size(policy1));
 }
 
-static const union fscrypt_policy *
-fscrypt_get_dummy_policy(struct super_block *sb)
+int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy,
+			       struct fscrypt_key_specifier *key_spec)
+{
+	switch (policy->version) {
+	case FSCRYPT_POLICY_V1:
+		key_spec->type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
+		memcpy(key_spec->u.descriptor, policy->v1.master_key_descriptor,
+		       FSCRYPT_KEY_DESCRIPTOR_SIZE);
+		return 0;
+	case FSCRYPT_POLICY_V2:
+		key_spec->type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
+		memcpy(key_spec->u.identifier, policy->v2.master_key_identifier,
+		       FSCRYPT_KEY_IDENTIFIER_SIZE);
+		return 0;
+	default:
+		WARN_ON_ONCE(1);
+		return -EINVAL;
+	}
+}
+
+const union fscrypt_policy *fscrypt_get_dummy_policy(struct super_block *sb)
 {
 	if (!sb->s_cop->get_dummy_policy)
 		return NULL;
 	return sb->s_cop->get_dummy_policy(sb);
 }
 
-static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode)
+/*
+ * Return %true if the given combination of encryption modes is supported for v1
+ * (and later) encryption policies.
+ *
+ * Do *not* add anything new here, since v1 encryption policies are deprecated.
+ * New combinations of modes should go in fscrypt_valid_enc_modes_v2() only.
+ */
+static bool fscrypt_valid_enc_modes_v1(u32 contents_mode, u32 filenames_mode)
 {
 	if (contents_mode == FSCRYPT_MODE_AES_256_XTS &&
 	    filenames_mode == FSCRYPT_MODE_AES_256_CTS)
@@ -57,6 +86,19 @@ static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode)
 	return false;
 }
 
+static bool fscrypt_valid_enc_modes_v2(u32 contents_mode, u32 filenames_mode)
+{
+	if (contents_mode == FSCRYPT_MODE_AES_256_XTS &&
+	    filenames_mode == FSCRYPT_MODE_AES_256_HCTR2)
+		return true;
+
+	if (contents_mode == FSCRYPT_MODE_SM4_XTS &&
+	    filenames_mode == FSCRYPT_MODE_SM4_CTS)
+		return true;
+
+	return fscrypt_valid_enc_modes_v1(contents_mode, filenames_mode);
+}
+
 static bool supported_direct_key_modes(const struct inode *inode,
 				       u32 contents_mode, u32 filenames_mode)
 {
@@ -78,12 +120,11 @@ static bool supported_direct_key_modes(const struct inode *inode,
 }
 
 static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
-					 const struct inode *inode,
-					 const char *type,
-					 int max_ino_bits, int max_lblk_bits)
+					 const struct inode *inode)
 {
+	const char *type = (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64)
+				? "IV_INO_LBLK_64" : "IV_INO_LBLK_32";
 	struct super_block *sb = inode->i_sb;
-	int ino_bits = 64, lblk_bits = 64;
 
 	/*
 	 * IV_INO_LBLK_* exist only because of hardware limitations, and
@@ -110,17 +151,29 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
 			     type, sb->s_id);
 		return false;
 	}
-	if (sb->s_cop->get_ino_and_lblk_bits)
-		sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
-	if (ino_bits > max_ino_bits) {
+
+	/*
+	 * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that inode numbers fit
+	 * in 32 bits.  In principle, IV_INO_LBLK_32 could support longer inode
+	 * numbers because it hashes the inode number; however, currently the
+	 * inode number is gotten from inode::i_ino which is 'unsigned long'.
+	 * So for now the implementation limit is 32 bits.
+	 */
+	if (!sb->s_cop->has_32bit_inodes) {
 		fscrypt_warn(inode,
 			     "Can't use %s policy on filesystem '%s' because its inode numbers are too long",
 			     type, sb->s_id);
 		return false;
 	}
-	if (lblk_bits > max_lblk_bits) {
+
+	/*
+	 * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that file data unit
+	 * indices fit in 32 bits.
+	 */
+	if (fscrypt_max_file_dun_bits(sb,
+			fscrypt_policy_v2_du_bits(policy, inode)) > 32) {
 		fscrypt_warn(inode,
-			     "Can't use %s policy on filesystem '%s' because its block numbers are too long",
+			     "Can't use %s policy on filesystem '%s' because its maximum file size is too large",
 			     type, sb->s_id);
 		return false;
 	}
@@ -130,7 +183,7 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
 static bool fscrypt_supported_v1_policy(const struct fscrypt_policy_v1 *policy,
 					const struct inode *inode)
 {
-	if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
+	if (!fscrypt_valid_enc_modes_v1(policy->contents_encryption_mode,
 				     policy->filenames_encryption_mode)) {
 		fscrypt_warn(inode,
 			     "Unsupported encryption modes (contents %d, filenames %d)",
@@ -166,7 +219,7 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
 {
 	int count = 0;
 
-	if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
+	if (!fscrypt_valid_enc_modes_v2(policy->contents_encryption_mode,
 				     policy->filenames_encryption_mode)) {
 		fscrypt_warn(inode,
 			     "Unsupported encryption modes (contents %d, filenames %d)",
@@ -193,25 +246,39 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
 		return false;
 	}
 
+	if (policy->log2_data_unit_size) {
+		if (!inode->i_sb->s_cop->supports_subblock_data_units) {
+			fscrypt_warn(inode,
+				     "Filesystem does not support configuring crypto data unit size");
+			return false;
+		}
+		if (policy->log2_data_unit_size > inode->i_blkbits ||
+		    policy->log2_data_unit_size < SECTOR_SHIFT /* 9 */) {
+			fscrypt_warn(inode,
+				     "Unsupported log2_data_unit_size in encryption policy: %d",
+				     policy->log2_data_unit_size);
+			return false;
+		}
+		if (policy->log2_data_unit_size != inode->i_blkbits &&
+		    (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
+			/*
+			 * Not safe to enable yet, as we need to ensure that DUN
+			 * wraparound can only occur on a FS block boundary.
+			 */
+			fscrypt_warn(inode,
+				     "Sub-block data units not yet supported with IV_INO_LBLK_32");
+			return false;
+		}
+	}
+
 	if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&
 	    !supported_direct_key_modes(inode, policy->contents_encryption_mode,
 					policy->filenames_encryption_mode))
 		return false;
 
-	if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
-	    !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64",
-					  32, 32))
-		return false;
-
-	/*
-	 * IV_INO_LBLK_32 hashes the inode number, so in principle it can
-	 * support any ino_bits.  However, currently the inode number is gotten
-	 * from inode::i_ino which is 'unsigned long'.  So for now the
-	 * implementation limit is 32 bits.
-	 */
-	if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) &&
-	    !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32",
-					  32, 32))
+	if ((policy->flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |
+			      FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) &&
+	    !supported_iv_ino_lblk_policy(policy, inode))
 		return false;
 
 	if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) {
@@ -290,6 +357,7 @@ static int fscrypt_new_context(union fscrypt_context *ctx_u,
 		ctx->filenames_encryption_mode =
 			policy->filenames_encryption_mode;
 		ctx->flags = policy->flags;
+		ctx->log2_data_unit_size = policy->log2_data_unit_size;
 		memcpy(ctx->master_key_identifier,
 		       policy->master_key_identifier,
 		       sizeof(ctx->master_key_identifier));
@@ -350,6 +418,7 @@ int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
 		policy->filenames_encryption_mode =
 			ctx->filenames_encryption_mode;
 		policy->flags = ctx->flags;
+		policy->log2_data_unit_size = ctx->log2_data_unit_size;
 		memcpy(policy->__reserved, ctx->__reserved,
 		       sizeof(policy->__reserved));
 		memcpy(policy->master_key_identifier,
@@ -365,11 +434,11 @@ int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
 /* Retrieve an inode's encryption policy */
 static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy)
 {
-	const struct fscrypt_info *ci;
+	const struct fscrypt_inode_info *ci;
 	union fscrypt_context ctx;
 	int ret;
 
-	ci = fscrypt_get_info(inode);
+	ci = fscrypt_get_inode_info(inode);
 	if (ci) {
 		/* key available, use the cached policy */
 		*policy = ci->ci_policy;
@@ -423,7 +492,7 @@ static int set_encryption_policy(struct inode *inode,
 				     current->comm, current->pid);
 		break;
 	default:
-		WARN_ON(1);
+		WARN_ON_ONCE(1);
 		return -EINVAL;
 	}
 
@@ -465,7 +534,7 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
 		return -EFAULT;
 	policy.version = version;
 
-	if (!inode_owner_or_capable(&init_user_ns, inode))
+	if (!inode_owner_or_capable(&nop_mnt_idmap, inode))
 		return -EACCES;
 
 	ret = mnt_want_write_file(filp);
@@ -607,7 +676,7 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
 
 	/*
 	 * Both parent and child are encrypted, so verify they use the same
-	 * encryption policy.  Compare the fscrypt_info structs if the keys are
+	 * encryption policy.  Compare the cached policies if the keys are
 	 * available, otherwise retrieve and compare the fscrypt_contexts.
 	 *
 	 * Note that the fscrypt_context retrieval will be required frequently
@@ -658,13 +727,39 @@ const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir)
 		err = fscrypt_require_key(dir);
 		if (err)
 			return ERR_PTR(err);
-		return &dir->i_crypt_info->ci_policy;
+		return &fscrypt_get_inode_info_raw(dir)->ci_policy;
 	}
 
 	return fscrypt_get_dummy_policy(dir->i_sb);
 }
 
 /**
+ * fscrypt_context_for_new_inode() - create an encryption context for a new inode
+ * @ctx: where context should be written
+ * @inode: inode from which to fetch policy and nonce
+ *
+ * Given an in-core "prepared" (via fscrypt_prepare_new_inode) inode,
+ * generate a new context and write it to ctx. ctx _must_ be at least
+ * FSCRYPT_SET_CONTEXT_MAX_SIZE bytes.
+ *
+ * Return: size of the resulting context or a negative error code.
+ */
+int fscrypt_context_for_new_inode(void *ctx, struct inode *inode)
+{
+	struct fscrypt_inode_info *ci = fscrypt_get_inode_info_raw(inode);
+
+	BUILD_BUG_ON(sizeof(union fscrypt_context) !=
+			FSCRYPT_SET_CONTEXT_MAX_SIZE);
+
+	/* fscrypt_prepare_new_inode() should have set up the key already. */
+	if (WARN_ON_ONCE(!ci))
+		return -ENOKEY;
+
+	return fscrypt_new_context(ctx, &ci->ci_policy, ci->ci_nonce);
+}
+EXPORT_SYMBOL_GPL(fscrypt_context_for_new_inode);
+
+/**
  * fscrypt_set_context() - Set the fscrypt context of a new inode
  * @inode: a new inode
  * @fs_data: private data given by FS and passed to ->set_context()
@@ -676,101 +771,65 @@ const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir)
  */
 int fscrypt_set_context(struct inode *inode, void *fs_data)
 {
-	struct fscrypt_info *ci = inode->i_crypt_info;
+	struct fscrypt_inode_info *ci;
 	union fscrypt_context ctx;
 	int ctxsize;
 
-	/* fscrypt_prepare_new_inode() should have set up the key already. */
-	if (WARN_ON_ONCE(!ci))
-		return -ENOKEY;
-
-	BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
-	ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, ci->ci_nonce);
+	ctxsize = fscrypt_context_for_new_inode(&ctx, inode);
+	if (ctxsize < 0)
+		return ctxsize;
 
 	/*
 	 * This may be the first time the inode number is available, so do any
 	 * delayed key setup that requires the inode number.
 	 */
+	ci = fscrypt_get_inode_info_raw(inode);
 	if (ci->ci_policy.version == FSCRYPT_POLICY_V2 &&
-	    (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
-		const struct fscrypt_master_key *mk =
-			ci->ci_master_key->payload.data[0];
-
-		fscrypt_hash_inode_number(ci, mk);
-	}
+	    (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32))
+		fscrypt_hash_inode_number(ci, ci->ci_master_key);
 
 	return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data);
 }
 EXPORT_SYMBOL_GPL(fscrypt_set_context);
 
 /**
- * fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption'
- * @sb: the filesystem on which test_dummy_encryption is being specified
- * @arg: the argument to the test_dummy_encryption option.  May be NULL.
- * @dummy_policy: the filesystem's current dummy policy (input/output, see
- *		  below)
- *
- * Handle the test_dummy_encryption mount option by creating a dummy encryption
- * policy, saving it in @dummy_policy, and adding the corresponding dummy
- * encryption key to the filesystem.  If the @dummy_policy is already set, then
- * instead validate that it matches @arg.  Don't support changing it via
- * remount, as that is difficult to do safely.
+ * fscrypt_parse_test_dummy_encryption() - parse the test_dummy_encryption mount option
+ * @param: the mount option
+ * @dummy_policy: (input/output) the place to write the dummy policy that will
+ *	result from parsing the option.  Zero-initialize this.  If a policy is
+ *	already set here (due to test_dummy_encryption being given multiple
+ *	times), then this function will verify that the policies are the same.
  *
- * Return: 0 on success (dummy policy set, or the same policy is already set);
- *         -EEXIST if a different dummy policy is already set;
- *         or another -errno value.
+ * Return: 0 on success; -EINVAL if the argument is invalid; -EEXIST if the
+ *	   argument conflicts with one already specified; or -ENOMEM.
  */
-int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
-				      struct fscrypt_dummy_policy *dummy_policy)
+int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
+				struct fscrypt_dummy_policy *dummy_policy)
 {
-	struct fscrypt_key_specifier key_spec = { 0 };
-	int version;
-	union fscrypt_policy *policy = NULL;
+	const char *arg = "v2";
+	union fscrypt_policy *policy;
 	int err;
 
-	if (!arg)
-		arg = "v2";
-
-	if (!strcmp(arg, "v1")) {
-		version = FSCRYPT_POLICY_V1;
-		key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
-		memset(key_spec.u.descriptor, 0x42,
-		       FSCRYPT_KEY_DESCRIPTOR_SIZE);
-	} else if (!strcmp(arg, "v2")) {
-		version = FSCRYPT_POLICY_V2;
-		key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
-		/* key_spec.u.identifier gets filled in when adding the key */
-	} else {
-		err = -EINVAL;
-		goto out;
-	}
+	if (param->type == fs_value_is_string && *param->string)
+		arg = param->string;
 
 	policy = kzalloc(sizeof(*policy), GFP_KERNEL);
-	if (!policy) {
-		err = -ENOMEM;
-		goto out;
-	}
-
-	err = fscrypt_add_test_dummy_key(sb, &key_spec);
-	if (err)
-		goto out;
+	if (!policy)
+		return -ENOMEM;
 
-	policy->version = version;
-	switch (policy->version) {
-	case FSCRYPT_POLICY_V1:
+	if (!strcmp(arg, "v1")) {
+		policy->version = FSCRYPT_POLICY_V1;
 		policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
 		policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
-		memcpy(policy->v1.master_key_descriptor, key_spec.u.descriptor,
+		memset(policy->v1.master_key_descriptor, 0x42,
 		       FSCRYPT_KEY_DESCRIPTOR_SIZE);
-		break;
-	case FSCRYPT_POLICY_V2:
+	} else if (!strcmp(arg, "v2")) {
+		policy->version = FSCRYPT_POLICY_V2;
 		policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
 		policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
-		memcpy(policy->v2.master_key_identifier, key_spec.u.identifier,
-		       FSCRYPT_KEY_IDENTIFIER_SIZE);
-		break;
-	default:
-		WARN_ON(1);
+		fscrypt_get_test_dummy_key_identifier(
+				policy->v2.master_key_identifier);
+	} else {
 		err = -EINVAL;
 		goto out;
 	}
@@ -789,7 +848,25 @@ out:
 	kfree(policy);
 	return err;
 }
-EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption);
+EXPORT_SYMBOL_GPL(fscrypt_parse_test_dummy_encryption);
+
+/**
+ * fscrypt_dummy_policies_equal() - check whether two dummy policies are equal
+ * @p1: the first test dummy policy (may be unset)
+ * @p2: the second test dummy policy (may be unset)
+ *
+ * Return: %true if the dummy policies are both set and equal, or both unset.
+ */
+bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
+				  const struct fscrypt_dummy_policy *p2)
+{
+	if (!p1->policy && !p2->policy)
+		return true;
+	if (!p1->policy || !p2->policy)
+		return false;
+	return fscrypt_policies_equal(p1->policy, p2->policy);
+}
+EXPORT_SYMBOL_GPL(fscrypt_dummy_policies_equal);
 
 /**
  * fscrypt_show_test_dummy_encryption() - show '-o test_dummy_encryption'