From 32492093722636596018a799c438bfc04c343b40 Mon Sep 17 00:00:00 2001 From: Rich Salz Date: Mon, 6 Mar 2017 09:54:17 -0500 Subject: [PATCH] Fix an endless loop in rsa_builtin_keygen. Cherry-picked by Matt Caswell from 69795831. Reviewed-by: Richard Levitte Reviewed-by: Matt Caswell (Merged from https://github.com/openssl/openssl/pull/4670) --- crypto/rsa/rsa_gen.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/crypto/rsa/rsa_gen.c b/crypto/rsa/rsa_gen.c index 082c8da2ef..a85493d609 100644 --- a/crypto/rsa/rsa_gen.c +++ b/crypto/rsa/rsa_gen.c @@ -110,6 +110,16 @@ static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, int bitsp, bitsq, ok = -1, n = 0; BN_CTX *ctx = NULL; + /* + * When generating ridiculously small keys, we can get stuck + * continually regenerating the same prime values. + */ + if (bits < 16) { + ok = 0; /* we set our own err */ + RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL); + goto err; + } + ctx = BN_CTX_new(); if (ctx == NULL) goto err; @@ -161,21 +171,10 @@ static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, if (!BN_GENCB_call(cb, 3, 0)) goto err; for (;;) { - /* - * When generating ridiculously small keys, we can get stuck - * continually regenerating the same prime values. Check for this and - * bail if it happens 3 times. - */ - unsigned int degenerate = 0; do { if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb)) goto err; - } while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3)); - if (degenerate == 3) { - ok = 0; /* we set our own err */ - RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL); - goto err; - } + } while (BN_cmp(rsa->p, rsa->q) == 0); if (!BN_sub(r2, rsa->q, BN_value_one())) goto err; if (!BN_gcd(r1, r2, rsa->e, ctx)) -- 2.25.1