| Upstream-Status: Backport |
| https://git.lysator.liu.se/nettle/nettle/commit/c71d2c9d20eeebb985e3872e4550137209e3ce4d |
| |
| CVE: CVE-2015-8803 |
| CVE: CVE-2015-8805 |
| |
| Same fix for both. |
| |
| Signed-off-by: Armin Kuster <akuster@mvista.com> |
| |
| Index: nettle-2.7.1/ecc-256.c |
| =================================================================== |
| --- nettle-2.7.1.orig/ecc-256.c |
| +++ nettle-2.7.1/ecc-256.c |
| @@ -96,9 +96,19 @@ ecc_256_modp (const struct ecc_curve *ec |
| q2 += t + (q1 < t); |
| |
| assert (q2 < 2); |
| + /* |
| + n-1 n-2 n-3 n-4 |
| + +---+---+---+---+ |
| + | u1| u0| u low | |
| + +---+---+---+---+ |
| + - | q1(2^96-1)| |
| + +-------+---+ |
| + |q2(2^.)| |
| + +-------+ |
| |
| - /* We multiply by two low limbs of p, 2^96 - 1, so we could use |
| - shifts rather than mul. */ |
| + We multiply by two low limbs of p, 2^96 - 1, so we could use |
| + shifts rather than mul. |
| + */ |
| t = mpn_submul_1 (rp + n - 4, ecc->p, 2, q1); |
| t += cnd_sub_n (q2, rp + n - 3, ecc->p, 1); |
| t += (-q2) & 0xffffffff; |
| @@ -108,7 +118,10 @@ ecc_256_modp (const struct ecc_curve *ec |
| u0 -= t; |
| t = (u1 < cy); |
| u1 -= cy; |
| - u1 += cnd_add_n (t, rp + n - 4, ecc->p, 3); |
| + |
| + cy = cnd_add_n (t, rp + n - 4, ecc->p, 2); |
| + u0 += cy; |
| + u1 += (u0 < cy); |
| u1 -= (-t) & 0xffffffff; |
| } |
| rp[2] = u0; |
| @@ -195,7 +208,7 @@ ecc_256_modq (const struct ecc_curve *ec |
| |
| /* Conditional add of p */ |
| u1 += t; |
| - u2 += (t<<32) + (u0 < t); |
| + u2 += (t<<32) + (u1 < t); |
| |
| t = cnd_add_n (t, rp + n - 4, ecc->q, 2); |
| u1 += t; |
| Index: nettle-2.7.1/ChangeLog |
| =================================================================== |
| --- nettle-2.7.1.orig/ChangeLog |
| +++ nettle-2.7.1/ChangeLog |
| @@ -1,3 +1,9 @@ |
| +2015-12-10 Niels Möller <nisse@lysator.liu.se> |
| + |
| + * ecc-256.c (ecc_256_modp): Fixed carry propagation bug. Problem |
| + reported by Hanno Böck. |
| + (ecc_256_modq): Fixed another carry propagation bug. |
| + |
| 2013-05-28 Niels Möller <nisse@lysator.liu.se> |
| |
| * Released nettle-2.7.1. |