From fb28c54347fcf4957b9b8ee7dee423d859eb7820 Mon Sep 17 00:00:00 2001 From: Ross Burton Date: Wed, 19 Jul 2017 14:27:32 +0100 Subject: libgcrypt: fix CVE-2017-9526 In libgcrypt before 1.7.7, an attacker who learns the EdDSA session key (from side-channel observation during the signing process) can easily recover the long-term secret key. 1.7.7 makes a cipher/ecc-eddsa.c change to store this session key in secure memory, to ensure that constant-time point operations are used in the MPI library. Signed-off-by: Ross Burton Signed-off-by: Richard Purdie --- ...-Store-EdDSA-session-key-in-secure-memory.patch | 39 ++++++++++++++++++++++ meta/recipes-support/libgcrypt/libgcrypt.inc | 1 + 2 files changed, 40 insertions(+) create mode 100644 meta/recipes-support/libgcrypt/files/0001-ecc-Store-EdDSA-session-key-in-secure-memory.patch diff --git a/meta/recipes-support/libgcrypt/files/0001-ecc-Store-EdDSA-session-key-in-secure-memory.patch b/meta/recipes-support/libgcrypt/files/0001-ecc-Store-EdDSA-session-key-in-secure-memory.patch new file mode 100644 index 0000000000..f6c4ca76f3 --- /dev/null +++ b/meta/recipes-support/libgcrypt/files/0001-ecc-Store-EdDSA-session-key-in-secure-memory.patch @@ -0,0 +1,39 @@ +CVE: CVE-2017-9526 +Upstream-Status: Backport +Signed-off-by: Ross Burton + +From b3cab278eb9c2ceda79f980bc26460d97f260041 Mon Sep 17 00:00:00 2001 +From: Jo Van Bulck +Date: Thu, 19 Jan 2017 17:00:15 +0100 +Subject: [PATCH] ecc: Store EdDSA session key in secure memory. + +* cipher/ecc-eddsa.c (_gcry_ecc_eddsa_sign): use mpi_snew to allocate +session key. +-- + +An attacker who learns the EdDSA session key from side-channel +observation during the signing process, can easily revover the long- +term secret key. Storing the session key in secure memory ensures that +constant time point operations are used in the MPI library. + +Signed-off-by: Jo Van Bulck +--- + cipher/ecc-eddsa.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/cipher/ecc-eddsa.c b/cipher/ecc-eddsa.c +index f91f8489..813e030d 100644 +--- a/cipher/ecc-eddsa.c ++++ b/cipher/ecc-eddsa.c +@@ -603,7 +603,7 @@ _gcry_ecc_eddsa_sign (gcry_mpi_t input, ECC_secret_key *skey, + a = mpi_snew (0); + x = mpi_new (0); + y = mpi_new (0); +- r = mpi_new (0); ++ r = mpi_snew (0); + ctx = _gcry_mpi_ec_p_internal_new (skey->E.model, skey->E.dialect, 0, + skey->E.p, skey->E.a, skey->E.b); + b = (ctx->nbits+7)/8; +-- +2.11.0 + diff --git a/meta/recipes-support/libgcrypt/libgcrypt.inc b/meta/recipes-support/libgcrypt/libgcrypt.inc index 404f870db0..8e7a38f894 100644 --- a/meta/recipes-support/libgcrypt/libgcrypt.inc +++ b/meta/recipes-support/libgcrypt/libgcrypt.inc @@ -18,6 +18,7 @@ SRC_URI = "ftp://ftp.gnupg.org/gcrypt/libgcrypt/libgcrypt-${PV}.tar.gz \ file://add-pkgconfig-support.patch \ file://libgcrypt-fix-building-error-with-O2-in-sysroot-path.patch \ file://fix-ICE-failure-on-mips-with-option-O-and-g.patch \ + file://0001-ecc-Store-EdDSA-session-key-in-secure-memory.patch \ file://CVE-2017-7526.patch \ " -- cgit 1.2.3-korg