From 1bf67b900fb4955a0b09f3c1cbe1ce7177adbe2f Mon Sep 17 00:00:00 2001 From: Tobias Brunner Date: Wed, 29 Mar 2017 11:26:24 +0200 Subject: [PATCH] gmp: Make sure the modulus is odd and the exponent not zero Unlike mpz_powm() its secure replacement mpz_powm_sec() has the additional requirement that the exponent must be > 0 and the modulus has to be odd. Otherwise, it will crash with a floating-point exception. Fixes: CVE-2017-9022 --- src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c index 2b2c7f249590..32a72ac9600b 100644 --- a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c +++ b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c @@ -475,7 +475,7 @@ gmp_rsa_public_key_t *gmp_rsa_public_key_load(key_type_t type, va_list args) } break; } - if (!e.ptr || !n.ptr) + if (!e.len || !n.len || (n.ptr[n.len-1] & 0x01) == 0) { return NULL; } @@ -506,5 +506,10 @@ gmp_rsa_public_key_t *gmp_rsa_public_key_load(key_type_t type, va_list args) this->k = (mpz_sizeinbase(this->n, 2) + 7) / BITS_PER_BYTE; + if (!mpz_sgn(this->e)) + { + destroy(this); + return NULL; + } return &this->public; } -- 1.9.1