From 1ee04b791b396385cce2a0c46c112158b2005293 Mon Sep 17 00:00:00 2001 From: Shane Lontis Date: Tue, 25 May 2021 13:31:44 +1000 Subject: [PATCH] Fix buffer overflow when generating large RSA keys in FIPS mode. A pairwise test runs only in FIPS mode. An assumption about the size of the 'to' buffer passed to RSA_private_decrypt() was incorrect. It needs to be up to RSA_size() bytes long - so a fixed buffer of 256 bytes was not large enough. An exiting malloc has increased in size to allocate buffer space for both the encrypt and decrypt buffer. The existing test used 2080 bits which was not quite large enough to trigger the issue. A test using 3072 bits has been added. Reported by Mark Powers from Acumen. Reviewed-by: Tomas Mraz Reviewed-by: Paul Dale (Merged from https://github.com/openssl/openssl/pull/15447) --- crypto/rsa/rsa_gen.c | 9 +++++++-- test/recipes/15-test_genrsa.t | 8 +++++++- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/crypto/rsa/rsa_gen.c b/crypto/rsa/rsa_gen.c index 07a3a7800e..ac64483e6a 100644 --- a/crypto/rsa/rsa_gen.c +++ b/crypto/rsa/rsa_gen.c @@ -479,7 +479,7 @@ static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg) unsigned int ciphertxt_len; unsigned char *ciphertxt = NULL; const unsigned char plaintxt[16] = {0}; - unsigned char decoded[256]; + unsigned char *decoded = NULL; unsigned int decoded_len; unsigned int plaintxt_len = (unsigned int)sizeof(plaintxt_len); int padding = RSA_PKCS1_PADDING; @@ -492,9 +492,14 @@ static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg) OSSL_SELF_TEST_DESC_PCT_RSA_PKCS1); ciphertxt_len = RSA_size(rsa); - ciphertxt = OPENSSL_zalloc(ciphertxt_len); + /* + * RSA_private_encrypt() and RSA_private_decrypt() requires the 'to' + * parameter to be a maximum of RSA_size() - allocate space for both. + */ + ciphertxt = OPENSSL_zalloc(ciphertxt_len * 2); if (ciphertxt == NULL) goto err; + decoded = ciphertxt + ciphertxt_len; ciphertxt_len = RSA_public_encrypt(plaintxt_len, plaintxt, ciphertxt, rsa, padding); diff --git a/test/recipes/15-test_genrsa.t b/test/recipes/15-test_genrsa.t index 95390c5ff4..501d3a100f 100644 --- a/test/recipes/15-test_genrsa.t +++ b/test/recipes/15-test_genrsa.t @@ -24,7 +24,7 @@ use lib bldtop_dir('.'); my $no_fips = disabled('fips') || ($ENV{NO_FIPS} // 0); plan tests => - ($no_fips ? 0 : 1) # Extra FIPS related test + ($no_fips ? 0 : 2) # Extra FIPS related test + 13; # We want to know that an absurdly small number of bits isn't support @@ -131,4 +131,10 @@ unless ($no_fips) { '-pkeyopt', 'bits:2080', '-out', 'genrsatest2080.pem'])), "Generating RSA key with > 2048 bits and < 3072 bits"); + ok(run(app(['openssl', 'genpkey', + @prov, + '-algorithm', 'RSA', + '-pkeyopt', 'bits:3072', + '-out', 'genrsatest3072.pem'])), + "Generating RSA key with 3072 bits"); } -- GitLab