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@@ -11,10 +11,10 @@
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#define pr_fmt(fmt) "RSA: "fmt
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#include <linux/module.h>
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-#include <linux/kernel.h>
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#include <linux/slab.h>
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+#include <crypto/akcipher.h>
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+#include <crypto/public_key.h>
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#include <crypto/algapi.h>
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-#include "public_key.h"
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("RSA Public Key Algorithm");
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@@ -84,72 +84,10 @@ static const struct {
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#undef _
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};
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-/*
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- * RSAVP1() function [RFC3447 sec 5.2.2]
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- */
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-static int RSAVP1(const struct public_key *key, MPI s, MPI *_m)
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-{
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- MPI m;
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- int ret;
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-
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- /* (1) Validate 0 <= s < n */
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- if (mpi_cmp_ui(s, 0) < 0) {
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- kleave(" = -EBADMSG [s < 0]");
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- return -EBADMSG;
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- }
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- if (mpi_cmp(s, key->rsa.n) >= 0) {
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- kleave(" = -EBADMSG [s >= n]");
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- return -EBADMSG;
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- }
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-
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- m = mpi_alloc(0);
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- if (!m)
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- return -ENOMEM;
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-
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- /* (2) m = s^e mod n */
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- ret = mpi_powm(m, s, key->rsa.e, key->rsa.n);
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- if (ret < 0) {
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- mpi_free(m);
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- return ret;
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- }
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-
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- *_m = m;
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- return 0;
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-}
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-
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-/*
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- * Integer to Octet String conversion [RFC3447 sec 4.1]
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- */
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-static int RSA_I2OSP(MPI x, size_t xLen, u8 **pX)
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-{
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- unsigned X_size, x_size;
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- int X_sign;
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- u8 *X;
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-
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- /* Make sure the string is the right length. The number should begin
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- * with { 0x00, 0x01, ... } so we have to account for 15 leading zero
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- * bits not being reported by MPI.
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- */
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- x_size = mpi_get_nbits(x);
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- pr_devel("size(x)=%u xLen*8=%zu\n", x_size, xLen * 8);
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- if (x_size != xLen * 8 - 15)
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- return -ERANGE;
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-
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- X = mpi_get_buffer(x, &X_size, &X_sign);
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- if (!X)
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- return -ENOMEM;
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- if (X_sign < 0) {
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- kfree(X);
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- return -EBADMSG;
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- }
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- if (X_size != xLen - 1) {
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- kfree(X);
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- return -EBADMSG;
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- }
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-
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- *pX = X;
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- return 0;
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-}
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+struct rsa_completion {
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+ struct completion completion;
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+ int err;
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+};
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/*
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* Perform the RSA signature verification.
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@@ -160,7 +98,7 @@ static int RSA_I2OSP(MPI x, size_t xLen, u8 **pX)
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* @asn1_template: The DigestInfo ASN.1 template
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* @asn1_size: Size of asm1_template[]
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*/
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-static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
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+static int rsa_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
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const u8 *asn1_template, size_t asn1_size)
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{
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unsigned PS_end, T_offset, i;
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@@ -170,9 +108,11 @@ static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
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if (k < 2 + 1 + asn1_size + hash_size)
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return -EBADMSG;
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- /* Decode the EMSA-PKCS1-v1_5 */
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- if (EM[1] != 0x01) {
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- kleave(" = -EBADMSG [EM[1] == %02u]", EM[1]);
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+ /* Decode the EMSA-PKCS1-v1_5
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+ * note: leading zeros are stripped by the RSA implementation
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+ */
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+ if (EM[0] != 0x01) {
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+ kleave(" = -EBADMSG [EM[0] == %02u]", EM[0]);
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return -EBADMSG;
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}
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@@ -183,7 +123,7 @@ static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
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return -EBADMSG;
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}
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- for (i = 2; i < PS_end; i++) {
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+ for (i = 1; i < PS_end; i++) {
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if (EM[i] != 0xff) {
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kleave(" = -EBADMSG [EM[PS%x] == %02u]", i - 2, EM[i]);
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return -EBADMSG;
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@@ -204,75 +144,81 @@ static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
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return 0;
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}
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-/*
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- * Perform the verification step [RFC3447 sec 8.2.2].
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- */
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-static int RSA_verify_signature(const struct public_key *key,
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- const struct public_key_signature *sig)
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+static void public_key_verify_done(struct crypto_async_request *req, int err)
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{
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- size_t tsize;
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- int ret;
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+ struct rsa_completion *compl = req->data;
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- /* Variables as per RFC3447 sec 8.2.2 */
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- const u8 *H = sig->digest;
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- u8 *EM = NULL;
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- MPI m = NULL;
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- size_t k;
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+ if (err == -EINPROGRESS)
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+ return;
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- kenter("");
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-
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- if (!RSA_ASN1_templates[sig->pkey_hash_algo].data)
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- return -ENOTSUPP;
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-
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- /* (1) Check the signature size against the public key modulus size */
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- k = mpi_get_nbits(key->rsa.n);
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- tsize = mpi_get_nbits(sig->rsa.s);
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+ compl->err = err;
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+ complete(&compl->completion);
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+}
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- /* According to RFC 4880 sec 3.2, length of MPI is computed starting
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- * from most significant bit. So the RFC 3447 sec 8.2.2 size check
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- * must be relaxed to conform with shorter signatures - so we fail here
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- * only if signature length is longer than modulus size.
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- */
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- pr_devel("step 1: k=%zu size(S)=%zu\n", k, tsize);
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- if (k < tsize) {
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- ret = -EBADMSG;
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- goto error;
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+int rsa_verify_signature(const struct public_key *pkey,
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+ const struct public_key_signature *sig)
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+{
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+ struct crypto_akcipher *tfm;
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+ struct akcipher_request *req;
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+ struct rsa_completion compl;
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+ struct scatterlist sig_sg, sg_out;
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+ void *outbuf = NULL;
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+ unsigned int outlen = 0;
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+ int ret = -ENOMEM;
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+
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+ tfm = crypto_alloc_akcipher("rsa", 0, 0);
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+ if (IS_ERR(tfm))
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+ goto error_out;
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+
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+ req = akcipher_request_alloc(tfm, GFP_KERNEL);
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+ if (!req)
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+ goto error_free_tfm;
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+
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+ ret = crypto_akcipher_set_pub_key(tfm, pkey->key, pkey->keylen);
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+ if (ret)
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+ goto error_free_req;
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+
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+ ret = -EINVAL;
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+ outlen = crypto_akcipher_maxsize(tfm);
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+ if (!outlen)
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+ goto error_free_req;
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+
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+ /* Initialize the output buffer */
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+ ret = -ENOMEM;
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+ outbuf = kmalloc(outlen, GFP_KERNEL);
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+ if (!outbuf)
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+ goto error_free_req;
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+
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+ sg_init_one(&sig_sg, sig->s, sig->s_size);
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+ sg_init_one(&sg_out, outbuf, outlen);
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+ akcipher_request_set_crypt(req, &sig_sg, &sg_out, sig->s_size, outlen);
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+ init_completion(&compl.completion);
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+ akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
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+ CRYPTO_TFM_REQ_MAY_SLEEP,
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+ public_key_verify_done, &compl);
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+
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+ ret = crypto_akcipher_verify(req);
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+ if (ret == -EINPROGRESS) {
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+ wait_for_completion(&compl.completion);
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+ ret = compl.err;
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}
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- /* Round up and convert to octets */
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- k = (k + 7) / 8;
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+ if (ret)
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+ goto error_free_req;
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- /* (2b) Apply the RSAVP1 verification primitive to the public key */
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- ret = RSAVP1(key, sig->rsa.s, &m);
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- if (ret < 0)
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- goto error;
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-
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- /* (2c) Convert the message representative (m) to an encoded message
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- * (EM) of length k octets.
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- *
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- * NOTE! The leading zero byte is suppressed by MPI, so we pass a
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- * pointer to the _preceding_ byte to RSA_verify()!
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+ /* Output from the operation is an encoded message (EM) of
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+ * length k octets.
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*/
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- ret = RSA_I2OSP(m, k, &EM);
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- if (ret < 0)
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- goto error;
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-
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- ret = RSA_verify(H, EM - 1, k, sig->digest_size,
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+ outlen = req->dst_len;
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+ ret = rsa_verify(sig->digest, outbuf, outlen, sig->digest_size,
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RSA_ASN1_templates[sig->pkey_hash_algo].data,
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RSA_ASN1_templates[sig->pkey_hash_algo].size);
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-
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-error:
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- kfree(EM);
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- mpi_free(m);
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- kleave(" = %d", ret);
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+error_free_req:
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+ akcipher_request_free(req);
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+error_free_tfm:
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+ crypto_free_akcipher(tfm);
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+error_out:
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+ kfree(outbuf);
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return ret;
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}
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-
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-const struct public_key_algorithm RSA_public_key_algorithm = {
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- .name = "RSA",
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- .n_pub_mpi = 2,
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- .n_sec_mpi = 3,
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- .n_sig_mpi = 1,
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- .verify_signature = RSA_verify_signature,
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-};
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-EXPORT_SYMBOL_GPL(RSA_public_key_algorithm);
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+EXPORT_SYMBOL_GPL(rsa_verify_signature);
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