From 904fcce0c63d5e7d6769cd8058445403ce9c9799 Mon Sep 17 00:00:00 2001 From: Emilia Kasper Date: Thu, 28 Aug 2014 19:43:49 +0200 Subject: RT3066: rewrite RSA padding checks to be slightly more constant time. Also tweak s3_cbc.c to use new constant-time methods. Also fix memory leaks from internal errors in RSA_padding_check_PKCS1_OAEP_mgf1 This patch is based on the original RT submission by Adam Langley , as well as code from BoringSSL and OpenSSL. Reviewed-by: Kurt Roeckx Conflicts: crypto/rsa/rsa_oaep.c --- ssl/s3_cbc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'ssl/s3_cbc.c') diff --git a/ssl/s3_cbc.c b/ssl/s3_cbc.c index 45a1495cbe..b826b20c86 100644 --- a/ssl/s3_cbc.c +++ b/ssl/s3_cbc.c @@ -96,7 +96,7 @@ int ssl3_cbc_remove_padding(const SSL* s, padding_length = good & (padding_length+1); rec->length -= padding_length; rec->type |= padding_length<<8; /* kludge: pass padding length */ - return (int)((good & 1) | (~good & -1)); + return constant_time_select_int(good, 1, -1); } /* tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC @@ -186,7 +186,7 @@ int tls1_cbc_remove_padding(const SSL* s, rec->length -= padding_length; rec->type |= padding_length<<8; /* kludge: pass padding length */ - return (int)((good & 1) | (~good & -1)); + return constant_time_select_int(good, 1, -1); } /* ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in @@ -641,7 +641,7 @@ void ssl3_cbc_digest_record( /* If this is the block containing the end of the * application data, and we are at the offset for the * 0x80 value, then overwrite b with 0x80. */ - b = (b&~is_past_c) | (0x80&is_past_c); + b = constant_time_select_8(is_past_c, 0x80, b); /* If this the the block containing the end of the * application data and we're past the 0x80 value then * just write zero. */ @@ -657,7 +657,8 @@ void ssl3_cbc_digest_record( if (j >= md_block_size - md_length_size) { /* If this is index_b, write a length byte. */ - b = (b&~is_block_b) | (is_block_b&length_bytes[j-(md_block_size-md_length_size)]); + b = constant_time_select_8( + is_block_b, length_bytes[j-(md_block_size-md_length_size)], b); } block[j] = b; } -- cgit v1.2.1