From f13a47bbb2f1dbcc718d9ddd5c7a4acc3232e045 Mon Sep 17 00:00:00 2001 From: Paul Elliott Date: Thu, 25 Feb 2021 12:28:49 +0000 Subject: [PATCH] Fixes for MSVC warnings Also added a couple of missing comment blocks. Signed-off-by: Paul Elliott --- library/base64.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/library/base64.c b/library/base64.c index 49a0612d2..201055b67 100644 --- a/library/base64.c +++ b/library/base64.c @@ -96,6 +96,9 @@ static const unsigned char base64_dec_map[128] = #define BASE64_SIZE_T_MAX ( (size_t) -1 ) /* SIZE_T_MAX is not standard */ +/* + * Constant flow conditional assignment +*/ static void mbedtls_base64_cond_assign(unsigned char * dest, const unsigned char * const src, unsigned char condition) { @@ -106,19 +109,31 @@ static void mbedtls_base64_cond_assign(unsigned char * dest, const unsigned char } /* - * Constant time check for equality + * Constant flow check for equality */ -static unsigned char mbedtls_base64_eq(uint32_t in_a, uint32_t in_b) +static unsigned char mbedtls_base64_eq(size_t in_a, size_t in_b) { uint32_t difference = in_a ^ in_b; + /* MSVC has a warning about unary minus on unsigned integer types, + * but this is well-defined and precisely what we want to do here. */ +#if defined(_MSC_VER) +#pragma warning( push ) +#pragma warning( disable : 4146 ) +#endif + difference |= -difference; + +#if defined(_MSC_VER) +#pragma warning( pop ) +#endif + difference >>= 31; return (unsigned char) ( 1 ^ difference ); } /* - * Constant time lookup into table. + * Constant flow lookup into table. */ static unsigned char mbedtls_base64_table_lookup(const unsigned char * const table, const size_t table_size, const size_t table_index)