From 70de68c4e4affcfb4ee2aed9157cda417522bfd1 Mon Sep 17 00:00:00 2001 From: Tomas Mraz Date: Tue, 4 Jul 2023 17:30:35 +0200 Subject: [PATCH] Do not ignore empty associated data with AES-SIV mode The AES-SIV mode allows for multiple associated data items authenticated separately with any of these being 0 length. The provided implementation ignores such empty associated data which is incorrect in regards to the RFC 5297 and is also a security issue because such empty associated data then become unauthenticated if an application expects to authenticate them. Fixes CVE-2023-2975 Reviewed-by: Matt Caswell Reviewed-by: Paul Dale (Merged from https://github.com/openssl/openssl/pull/21384) (cherry picked from commit c426c281cfc23ab182f7d7d7a35229e7db1494d9) Signed-off-by: code4lala --- .../implementations/ciphers/cipher_aes_siv.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/providers/implementations/ciphers/cipher_aes_siv.c b/providers/implementations/ciphers/cipher_aes_siv.c index 45010b90db..b396c8651a 100644 --- a/providers/implementations/ciphers/cipher_aes_siv.c +++ b/providers/implementations/ciphers/cipher_aes_siv.c @@ -120,14 +120,18 @@ static int siv_cipher(void *vctx, unsigned char *out, size_t *outl, if (!ossl_prov_is_running()) return 0; - if (inl == 0) { - *outl = 0; - return 1; - } + /* Ignore just empty encryption/decryption call and not AAD. */ + if (out != NULL) { + if (inl == 0) { + if (outl != NULL) + *outl = 0; + return 1; + } - if (outsize < inl) { - ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL); - return 0; + if (outsize < inl) { + ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL); + return 0; + } } if (ctx->hw->cipher(ctx, out, in, inl) <= 0) -- GitLab