diff --git a/include/linux/asn1_encoder.h b/include/linux/asn1_encoder.h
new file mode 100644
index 000000000000..08cd0c2ad34f
--- /dev/null
+++ b/include/linux/asn1_encoder.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _LINUX_ASN1_ENCODER_H
+#define _LINUX_ASN1_ENCODER_H
+
+#include <linux/types.h>
+#include <linux/asn1.h>
+#include <linux/asn1_ber_bytecode.h>
+#include <linux/bug.h>
+
+#define asn1_oid_len(oid) (sizeof(oid)/sizeof(u32))
+unsigned char *
+asn1_encode_integer(unsigned char *data, const unsigned char *end_data,
+		    s64 integer);
+unsigned char *
+asn1_encode_oid(unsigned char *data, const unsigned char *end_data,
+		u32 oid[], int oid_len);
+unsigned char *
+asn1_encode_tag(unsigned char *data, const unsigned char *end_data,
+		u32 tag, const unsigned char *string, int len);
+unsigned char *
+asn1_encode_octet_string(unsigned char *data,
+			 const unsigned char *end_data,
+			 const unsigned char *string, u32 len);
+unsigned char *
+asn1_encode_sequence(unsigned char *data, const unsigned char *end_data,
+		     const unsigned char *seq, int len);
+unsigned char *
+asn1_encode_boolean(unsigned char *data, const unsigned char *end_data,
+		    bool val);
+
+#endif
diff --git a/lib/Makefile b/lib/Makefile
index c2f0e2a4e4e8..515b35f92c3c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -233,7 +233,7 @@ obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o
 
 obj-$(CONFIG_PERCPU_TEST) += percpu_test.o
 
-obj-$(CONFIG_ASN1) += asn1_decoder.o
+obj-$(CONFIG_ASN1) += asn1_decoder.o asn1_encoder.o
 
 obj-$(CONFIG_FONT_SUPPORT) += fonts/
 
diff --git a/lib/asn1_encoder.c b/lib/asn1_encoder.c
new file mode 100644
index 000000000000..e3d9631a50fd
--- /dev/null
+++ b/lib/asn1_encoder.c
@@ -0,0 +1,391 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple encoder primitives for ASN.1 BER/DER/CER
+ *
+ * Copyright (C) 2019 James.Bottomley@HansenPartnership.com
+ */
+
+#include <linux/asn1_encoder.h>
+#include <linux/bug.h>
+#include <linux/string.h>
+#include <linux/module.h>
+
+/**
+ * asn1_encode_integer - encode positive integer to ASN.1
+ * @data: pointer to the pointer to the data
+ * @end_data: end of data pointer, points one beyond last usable byte in @data
+ * @integer: integer to be encoded
+ *
+ * This is a simplified encoder: it only currently does
+ * positive integers, but it should be simple enough to add the
+ * negative case if a use comes along.
+ */
+unsigned char *
+asn1_encode_integer(unsigned char *data, const unsigned char *end_data,
+		    s64 integer)
+{
+	unsigned char *d = &data[2];
+	int i;
+	bool found = false;
+	int data_len = end_data - data;
+
+	if (WARN(integer < 0,
+		 "BUG: integer encode only supports positive integers"))
+		return ERR_PTR(-EINVAL);
+
+	if (IS_ERR(data))
+		return data;
+
+	if (data_len < 3)
+		return ERR_PTR(-EINVAL);
+
+	data_len -= 2;
+
+	data[0] = _tag(UNIV, PRIM, INT);
+	if (integer == 0) {
+		*d++ = 0;
+		goto out;
+	}
+	for (i = sizeof(integer); i > 0 ; i--) {
+		int byte = integer >> (8*(i-1));
+
+		if (!found && byte == 0)
+			continue;
+		/*
+		 * for a positive number the first byte must have bit
+		 * 7 clear in two's complement (otherwise it's a
+		 * negative number) so prepend a leading zero if
+		 * that's not the case
+		 */
+		if (!found && (byte & 0x80)) {
+			/*
+			 * no check needed here, we already know we
+			 * have len >= 1
+			 */
+			*d++ = 0;
+			data_len--;
+		}
+		found = true;
+		if (data_len == 0)
+			return ERR_PTR(-EINVAL);
+		*d++ = byte;
+		data_len--;
+	}
+ out:
+	data[1] = d - data - 2;
+
+	return d;
+}
+EXPORT_SYMBOL_GPL(asn1_encode_integer);
+
+/* calculate the base 128 digit values setting the top bit of the first octet */
+static int asn1_encode_oid_digit(unsigned char **_data, int *data_len, u32 oid)
+{
+	int start = 7 + 7 + 7 + 7;
+	unsigned char *data = *_data;
+	int ret = 0;
+
+	if (*data_len < 1)
+		return -EINVAL;
+
+	/* quick case */
+	if (oid == 0) {
+		*data++ = 0x80;
+		(*data_len)--;
+		goto out;
+	}
+
+	while (oid >> start == 0)
+		start -= 7;
+
+	while (start > 0 && *data_len > 0) {
+		u8 byte;
+
+		byte = oid >> start;
+		oid = oid - (byte << start);
+		start -= 7;
+		byte |= 0x80;
+		*data++ = byte;
+		(*data_len)--;
+	}
+	if (*data_len > 0) {
+		*data++ = oid;
+		(*data_len)--;
+	} else {
+		ret = -EINVAL;
+	}
+
+ out:
+	*_data = data;
+	return ret;
+}
+
+/**
+ * asn1_encode_oid - encode an oid to ASN.1
+ * @data: position to begin encoding at
+ * @end_data: end of data pointer, points one beyond last usable byte in @data
+ * @oid: array of oids
+ * @oid_len: length of oid array
+ *
+ * this encodes an OID up to ASN.1 when presented as an array of OID values
+ */
+unsigned char *
+asn1_encode_oid(unsigned char *data, const unsigned char *end_data,
+		u32 oid[], int oid_len)
+{
+	unsigned char *d = data + 2;
+	int i, ret;
+	int data_len = end_data - data;
+
+	if (WARN(oid_len < 2, "OID must have at least two elements"))
+		return ERR_PTR(-EINVAL);
+	if (WARN(oid_len > 32, "OID is too large"))
+		return ERR_PTR(-EINVAL);
+	if (IS_ERR(data))
+		return data;
+	if (data_len < 2)
+		return ERR_PTR(-EINVAL);
+
+	data[0] = _tag(UNIV, PRIM, OID);
+	*d++ = oid[0] * 40 + oid[1];
+	data_len -= 2;
+	ret = 0;
+	for (i = 2; i < oid_len; i++) {
+		ret = asn1_encode_oid_digit(&d, &data_len, oid[i]);
+		if (ret < 0)
+			return ERR_PTR(ret);
+	}
+	data[1] = d - data - 2;
+	return d;
+}
+EXPORT_SYMBOL_GPL(asn1_encode_oid);
+
+static int asn1_encode_length(unsigned char **data, int *data_len, int len)
+{
+	if (*data_len < 1)
+		return -EINVAL;
+	if (len < 0) {
+		*((*data)++) = ASN1_INDEFINITE_LENGTH;
+		(*data_len)--;
+		return 0;
+	}
+	if (len <= 0x7f) {
+		*((*data)++) = len;
+		(*data_len)--;
+		return 0;
+	}
+
+	if (*data_len < 2)
+		return -EINVAL;
+	if (len <= 0xff) {
+		*((*data)++) = 0x81;
+		*((*data)++) = len & 0xff;
+		*data_len -= 2;
+		return 0;
+	}
+
+	if (*data_len < 3)
+		return -EINVAL;
+	if (len <= 0xffff) {
+		*((*data)++) = 0x82;
+		*((*data)++) = (len >> 8) & 0xff;
+		*((*data)++) = len & 0xff;
+		*data_len -= 3;
+		return 0;
+	}
+
+	if (WARN(len > 0xffffff, "ASN.1 length can't be > 0xffffff"))
+		return -EINVAL;
+
+	if (*data_len < 4)
+		return -EINVAL;
+	*((*data)++) = 0x83;
+	*((*data)++) = (len >> 16) & 0xff;
+	*((*data)++) = (len >> 8) & 0xff;
+	*((*data)++) = len & 0xff;
+	*data_len -= 4;
+
+	return 0;
+}
+
+/**
+ * asn1_encode_tag - add a tag for optional or explicit value
+ * @data: pointer to place tag at
+ * @end_data: end of data pointer, points one beyond last usable byte in @data
+ * @tag: tag to be placed
+ * @string: the data to be tagged
+ * @len: the length of the data to be tagged
+ *
+ * Note this currently only handles short form tags < 31.  To encode
+ * in place pass a NULL @string and -1 for @len; all this will do is
+ * add an indefinite length tag and update the data pointer to the
+ * place where the tag contents should be placed.  After the data is
+ * placed, repeat the prior statement but now with the known length.
+ * In order to avoid having to keep both before and after pointers,
+ * the repeat expects to be called with @data pointing to where the
+ * first encode placed it.
+ */
+unsigned char *
+asn1_encode_tag(unsigned char *data, const unsigned char *end_data,
+		u32 tag, const unsigned char *string, int len)
+{
+	int ret;
+	int data_len = end_data - data;
+
+	if (WARN(tag > 30, "ASN.1 tag can't be > 30"))
+		return ERR_PTR(-EINVAL);
+
+	if (!string && WARN(len > 127,
+			    "BUG: recode tag is too big (>127)"))
+		return ERR_PTR(-EINVAL);
+	if (IS_ERR(data))
+		return data;
+
+	if (!string && len > 0) {
+		/*
+		 * we're recoding, so move back to the start of the
+		 * tag and install a dummy length because the real
+		 * data_len should be NULL
+		 */
+		data -= 2;
+		data_len = 2;
+	}
+
+	if (data_len < 2)
+		return ERR_PTR(-EINVAL);
+
+	*(data++) = _tagn(CONT, CONS, tag);
+	data_len--;
+	ret = asn1_encode_length(&data, &data_len, len);
+	if (ret < 0)
+		return ERR_PTR(ret);
+	if (!string)
+		return data;
+	if (data_len < len)
+		return ERR_PTR(-EINVAL);
+	memcpy(data, string, len);
+	data += len;
+
+	return data;
+}
+EXPORT_SYMBOL_GPL(asn1_encode_tag);
+
+/**
+ * asn1_encode_octet_string - encode an ASN.1 OCTET STRING
+ * @data: pointer to encode at
+ * @end_data: end of data pointer, points one beyond last usable byte in @data
+ * @string: string to be encoded
+ * @len: length of string
+ *
+ * Note ASN.1 octet strings may contain zeros, so the length is obligatory.
+ */
+unsigned char *
+asn1_encode_octet_string(unsigned char *data,
+			 const unsigned char *end_data,
+			 const unsigned char *string, u32 len)
+{
+	int ret;
+	int data_len = end_data - data;
+
+	if (IS_ERR(data))
+		return data;
+
+	if (data_len < 2)
+		return ERR_PTR(-EINVAL);
+
+	*(data++) = _tag(UNIV, PRIM, OTS);
+	data_len--;
+	ret = asn1_encode_length(&data, &data_len, len);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (data_len < len)
+		return ERR_PTR(-EINVAL);
+
+	memcpy(data, string, len);
+	data += len;
+
+	return data;
+}
+EXPORT_SYMBOL_GPL(asn1_encode_octet_string);
+
+/**
+ * asn1_encode_sequence - wrap a byte stream in an ASN.1 SEQUENCE
+ * @data: pointer to encode at
+ * @end_data: end of data pointer, points one beyond last usable byte in @data
+ * @seq: data to be encoded as a sequence
+ * @len: length of the data to be encoded as a sequence
+ *
+ * Fill in a sequence.  To encode in place, pass NULL for @seq and -1
+ * for @len; then call again once the length is known (still with NULL
+ * for @seq). In order to avoid having to keep both before and after
+ * pointers, the repeat expects to be called with @data pointing to
+ * where the first encode placed it.
+ */
+unsigned char *
+asn1_encode_sequence(unsigned char *data, const unsigned char *end_data,
+		     const unsigned char *seq, int len)
+{
+	int ret;
+	int data_len = end_data - data;
+
+	if (!seq && WARN(len > 127,
+			 "BUG: recode sequence is too big (>127)"))
+		return ERR_PTR(-EINVAL);
+	if (IS_ERR(data))
+		return data;
+	if (!seq && len >= 0) {
+		/*
+		 * we're recoding, so move back to the start of the
+		 * sequence and install a dummy length because the
+		 * real length should be NULL
+		 */
+		data -= 2;
+		data_len = 2;
+	}
+
+	if (data_len < 2)
+		return ERR_PTR(-EINVAL);
+
+	*(data++) = _tag(UNIV, CONS, SEQ);
+	data_len--;
+	ret = asn1_encode_length(&data, &data_len, len);
+	if (ret)
+		return ERR_PTR(ret);
+	if (!seq)
+		return data;
+
+	if (data_len < len)
+		return ERR_PTR(-EINVAL);
+
+	memcpy(data, seq, len);
+	data += len;
+
+	return data;
+}
+EXPORT_SYMBOL_GPL(asn1_encode_sequence);
+
+/**
+ * asn1_encode_boolean - encode a boolean value to ASN.1
+ * @data: pointer to encode at
+ * @end_data: end of data pointer, points one beyond last usable byte in @data
+ * @val: the boolean true/false value
+ */
+unsigned char *
+asn1_encode_boolean(unsigned char *data, const unsigned char *end_data,
+		    bool val)
+{
+	int data_len = end_data - data;
+
+	if (IS_ERR(data))
+		return data;
+	if (data_len < 3)
+		return ERR_PTR(-EINVAL);
+	*(data++) = _tag(UNIV, PRIM, BOOL);
+	data_len--;
+	asn1_encode_length(&data, &data_len, 1);
+	*(data++) = val ? 1 : 0;
+
+	return data;
+}
+EXPORT_SYMBOL_GPL(asn1_encode_boolean);
