From ef29e17a94b9cd0c4b6c48ada1a3e21766c9ab9b Mon Sep 17 00:00:00 2001 From: Paul Elliott Date: Mon, 10 May 2021 19:33:03 +0100 Subject: [PATCH] Add comment to non-obvious code guard Ad and body lengths can only be too big on builds where size_t is bigger than 32 bits. This checking code therefore generates always true comparison warnings on 32 bit platforms, and thus had to be guarded. Signed-off-by: Paul Elliott --- library/psa_crypto_aead.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/library/psa_crypto_aead.c b/library/psa_crypto_aead.c index ac4297ed40..29dbedeb7b 100644 --- a/library/psa_crypto_aead.c +++ b/library/psa_crypto_aead.c @@ -447,6 +447,9 @@ psa_status_t mbedtls_psa_aead_set_lengths( mbedtls_psa_aead_operation_t #if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM) if( operation->alg == PSA_ALG_GCM ) { + /* Lengths can only be too large for GCM if size_t is bigger than 32 + * bits. Without the guard this code will generate warnings on 32bit + builds */ #if SIZE_MAX > UINT32_MAX if( ( (uint64_t) ad_length ) >> 61 != 0 || ( (uint64_t) plaintext_length ) > 0xFFFFFFFE0ull )