Fix possible memory leak in BN_mpi2bn() if BN_bin2bn() fails.

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feedback from millert@
ok tb@

1 files changed, 7 insertions, 3 deletions

diff --git a/src/lib/libcrypto/bn/bn_mpi.c b/src/lib/libcrypto/bn/bn_mpi.c
index 4801192b50..9b743cca8c 100644
--- a/src/lib/libcrypto/bn/bn_mpi.c
+++ b/src/lib/libcrypto/bn/bn_mpi.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_mpi.c,v 1.8 2017/01/29 17:49:22 beck Exp $ */
+/* $OpenBSD: bn_mpi.c,v 1.9 2022/11/09 01:05:45 tobhe Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -92,8 +92,9 @@ BN_bn2mpi(const BIGNUM *a, unsigned char *d)
 }
 
 BIGNUM *
-BN_mpi2bn(const unsigned char *d, int n, BIGNUM *a)
+BN_mpi2bn(const unsigned char *d, int n, BIGNUM *ain)
 {
+        BIGNUM *a = ain;
         long len;
         int neg = 0;
 
@@ -121,8 +122,11 @@ BN_mpi2bn(const unsigned char *d, int n, BIGNUM *a)
         d += 4;
         if ((*d) & 0x80)
                 neg = 1;
-        if (BN_bin2bn(d, (int)len, a) == NULL)
+        if (BN_bin2bn(d, (int)len, a) == NULL) {
+                if (ain == NULL)
+                        BN_free(a);
                 return (NULL);
+        }
         a->neg = neg;
         if (neg) {
                 BN_clear_bit(a, BN_num_bits(a) - 1);