diff options
Diffstat (limited to 'security/openssl111/files/patch-CVE-2018-0734')
| -rw-r--r-- | security/openssl111/files/patch-CVE-2018-0734 | 98 |
1 files changed, 0 insertions, 98 deletions
diff --git a/security/openssl111/files/patch-CVE-2018-0734 b/security/openssl111/files/patch-CVE-2018-0734 deleted file mode 100644 index b2e8ad5c87bd..000000000000 --- a/security/openssl111/files/patch-CVE-2018-0734 +++ /dev/null @@ -1,98 +0,0 @@ -Timing vulnerability in DSA signature generation (CVE-2018-0734). - -Avoid a timing attack that leaks information via a side channel that -triggers when a BN is resized. Increasing the size of the BNs -prior to doing anything with them suppresses the attack. - -Thanks due to Samuel Weiser for finding and locating this. - -Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de> -(Merged from #7486) - -(cherry picked from commit a9cfb8c) - -https://github.com/openssl/openssl/commit/8abfe72e8c1de1b95f50aa0d9134803b4d00070f ---- crypto/dsa/dsa_ossl.c.orig 2018-09-11 12:48:21 UTC -+++ crypto/dsa/dsa_ossl.c -@@ -9,6 +9,7 @@ - - #include <stdio.h> - #include "internal/cryptlib.h" -+#include "internal/bn_int.h" - #include <openssl/bn.h> - #include <openssl/sha.h> - #include "dsa_locl.h" -@@ -178,9 +179,9 @@ static int dsa_sign_setup(DSA *dsa, BN_C - { - BN_CTX *ctx = NULL; - BIGNUM *k, *kinv = NULL, *r = *rp; -- BIGNUM *l, *m; -+ BIGNUM *l; - int ret = 0; -- int q_bits; -+ int q_bits, q_words; - - if (!dsa->p || !dsa->q || !dsa->g) { - DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_MISSING_PARAMETERS); -@@ -189,8 +190,7 @@ static int dsa_sign_setup(DSA *dsa, BN_C - - k = BN_new(); - l = BN_new(); -- m = BN_new(); -- if (k == NULL || l == NULL || m == NULL) -+ if (k == NULL || l == NULL) - goto err; - - if (ctx_in == NULL) { -@@ -201,9 +201,9 @@ static int dsa_sign_setup(DSA *dsa, BN_C - - /* Preallocate space */ - q_bits = BN_num_bits(dsa->q); -- if (!BN_set_bit(k, q_bits) -- || !BN_set_bit(l, q_bits) -- || !BN_set_bit(m, q_bits)) -+ q_words = bn_get_top(dsa->q); -+ if (!bn_wexpand(k, q_words + 2) -+ || !bn_wexpand(l, q_words + 2)) - goto err; - - /* Get random k */ -@@ -238,14 +238,17 @@ static int dsa_sign_setup(DSA *dsa, BN_C - * small timing information leakage. We then choose the sum that is - * one bit longer than the modulus. - * -- * TODO: revisit the BN_copy aiming for a memory access agnostic -- * conditional copy. -+ * There are some concerns about the efficacy of doing this. More -+ * specificly refer to the discussion starting with: -+ * https://github.com/openssl/openssl/pull/7486#discussion_r228323705 -+ * The fix is to rework BN so these gymnastics aren't required. - */ - if (!BN_add(l, k, dsa->q) -- || !BN_add(m, l, dsa->q) -- || !BN_copy(k, BN_num_bits(l) > q_bits ? l : m)) -+ || !BN_add(k, l, dsa->q)) - goto err; - -+ BN_consttime_swap(BN_is_bit_set(l, q_bits), k, l, q_words + 2); -+ - if ((dsa)->meth->bn_mod_exp != NULL) { - if (!dsa->meth->bn_mod_exp(dsa, r, dsa->g, k, dsa->p, ctx, - dsa->method_mont_p)) -@@ -258,7 +261,7 @@ static int dsa_sign_setup(DSA *dsa, BN_C - if (!BN_mod(r, r, dsa->q, ctx)) - goto err; - -- /* Compute part of 's = inv(k) (m + xr) mod q' */ -+ /* Compute part of 's = inv(k) (m + xr) mod q' */ - if ((kinv = BN_mod_inverse(NULL, k, dsa->q, ctx)) == NULL) - goto err; - -@@ -273,7 +276,6 @@ static int dsa_sign_setup(DSA *dsa, BN_C - BN_CTX_free(ctx); - BN_clear_free(k); - BN_clear_free(l); -- BN_clear_free(m); - return ret; - } - |