commit 7097447b84c6c31c8ffb7862c72143d089d6db81
author Gabor Mezei <gabor.mezei@arm.com> Fri Apr 21 17:28:25 2023 +0200
committer Gabor Mezei <gabor.mezei@arm.com> Wed Apr 26 14:08:35 2023 +0200
tree 82bac479c6d6dc2b750dbc1ce083620305cc6677
parent 8183c5dcc3624267493c3cc2f88488de587e9359

Ensure input parameter size for Koblitz reduction

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>

library/ecp_curves.c

diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index 029b515..55428d6 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -5597,7 +5597,13 @@
  */
 static int ecp_mod_p192k1(mbedtls_mpi *N)
 {
-    return mbedtls_ecp_mod_p192k1(N);
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    size_t expected_width = 2 * ((192 + biL - 1) / biL);
+    MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
+    ret = mbedtls_ecp_mod_p192k1(N);
+
+cleanup:
+    return ret;
 }
 
 MBEDTLS_STATIC_TESTABLE
@@ -5618,7 +5624,13 @@
 
 static int ecp_mod_p224k1(mbedtls_mpi *N)
 {
-    return mbedtls_ecp_mod_p224k1(N);
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    size_t expected_width =  2 * 224 / biL;
+    MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
+    ret = mbedtls_ecp_mod_p224k1(N);
+
+cleanup:
+    return ret;
 }
 
 /*
@@ -5647,7 +5659,13 @@
 
 static int ecp_mod_p256k1(mbedtls_mpi *N)
 {
-    return mbedtls_ecp_mod_p256k1(N);
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    size_t expected_width = 2 * ((256 + biL - 1) / biL);
+    MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
+    ret = mbedtls_ecp_mod_p256k1(N);
+
+cleanup:
+    return ret;
 }
 
 /*