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authorPeter Grehan <grehan@FreeBSD.org>2021-02-03 09:05:09 +0000
committerPeter Grehan <grehan@FreeBSD.org>2021-02-06 04:01:18 +0000
commit6136a10e355a7a837edecbccbed04c34b4bc32c9 (patch)
treeb8ff7c6758a69f91646da94385b7bd72039baae2
parent154207a59bd296d7192c9e4659d64992606e9cd2 (diff)
downloadsrc-6136a10e355a7a837edecbccbed04c34b4bc32c9.tar.gz
src-6136a10e355a7a837edecbccbed04c34b4bc32c9.zip
Always clamp curve25519 keys prior to use.
This fixes an issue where a private key contained bits that should have been cleared by the clamping process, but were passed through to the scalar multiplication routine and resulted in an invalid public key. Issue diagnosed (and an initial fix proposed) by shamaz.mazum in PR 252894. This fix suggested by Jason Donenfeld. PR: 252894 Reported by: shamaz.mazum (cherry picked from commit 5aaea4b99e5cc724e97e24a68876e8768d3d8012)
-rw-r--r--sys/dev/if_wg/module/curve25519.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/sys/dev/if_wg/module/curve25519.c b/sys/dev/if_wg/module/curve25519.c
index e21d00bd2818..16f0b0337eb6 100644
--- a/sys/dev/if_wg/module/curve25519.c
+++ b/sys/dev/if_wg/module/curve25519.c
@@ -767,6 +767,7 @@ void curve25519_generic(u8 out[CURVE25519_KEY_SIZE],
u8 e[32];
memcpy(e, scalar, 32);
+ curve25519_clamp_secret(e);
/* The following implementation was transcribed to Coq and proven to
* correspond to unary scalar multiplication in affine coordinates given