commit 9312ba530459c855b9549bfefefad01dd4000cb6
author Gilles Peskine <Gilles.Peskine@arm.com> Mon Mar 29 22:14:51 2021 +0200
committer Gilles Peskine <Gilles.Peskine@arm.com> Wed Jun 02 21:31:24 2021 +0200
tree 88a02147346fccbb6c04f4314d05aa7ef4954a17
parent 4699fa47d209a5facf1312c654fe889966a21a4e

mbedtls_mpi_random: check for invalid arguments

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

library/bignum.c

diff --git a/library/bignum.c b/library/bignum.c
index 1cde6b0..9145a3d 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -2445,6 +2445,11 @@
     size_t n_bits = mbedtls_mpi_bitlen( N );
     size_t n_bytes = ( n_bits + 7 ) / 8;
 
+    if( min < 0 )
+        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+    if( mbedtls_mpi_cmp_int( N, min ) <= 0 )
+        return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+
     /*
      * Match the procedure given in RFC 6979 §3.3 (deterministic ECDSA)
      * when f_rng is a suitably parametrized instance of HMAC_DRBG: