From 1d05eb55caa8965a151360c2469c463ecd990987 Mon Sep 17 00:00:00 2001 From: Tomas Mraz Date: Tue, 19 May 2020 10:51:53 +0200 Subject: [PATCH] Avoid potential overflow to the sign bit when shifting left 24 places Although there are platforms where int is 64 bit, 2GiB large BIGNUMs instead of 4GiB should be "big enough for everybody". Reviewed-by: Richard Levitte (Merged from https://github.com/openssl/openssl/pull/11857) --- crypto/bn/bn_mpi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/crypto/bn/bn_mpi.c b/crypto/bn/bn_mpi.c index 504cddffec..d2be44e2bd 100644 --- a/crypto/bn/bn_mpi.c +++ b/crypto/bn/bn_mpi.c @@ -45,7 +45,7 @@ BIGNUM *BN_mpi2bn(const unsigned char *d, int n, BIGNUM *ain) int neg = 0; BIGNUM *a = NULL; - if (n < 4) { + if (n < 4 || (d[0] & 0x80) != 0) { BNerr(BN_F_BN_MPI2BN, BN_R_INVALID_LENGTH); return NULL; } -- 2.34.1