From cf66f2357c6ad8c5fe219577ad56e6f51301ca5a Mon Sep 17 00:00:00 2001 From: Tim Ruffing Date: Mon, 5 Dec 2022 14:35:54 +0100 Subject: [PATCH] refactor: Add helper function secp256k1_context_is_proper() --- src/secp256k1.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/src/secp256k1.c b/src/secp256k1.c index 5ed38241610ae..d9626865cb0f3 100644 --- a/src/secp256k1.c +++ b/src/secp256k1.c @@ -75,6 +75,15 @@ static const secp256k1_context secp256k1_context_static_ = { const secp256k1_context *secp256k1_context_static = &secp256k1_context_static_; const secp256k1_context *secp256k1_context_no_precomp = &secp256k1_context_static_; +/* Helper function that determines if a context is proper, i.e., is not the static context or a copy thereof. + * + * This is intended for "context" functions such as secp256k1_context_clone. Function which need specific + * features of a context should still check for these features directly. For example, a function that needs + * ecmult_gen should directly check for the existence of the ecmult_gen context. */ +static int secp256k1_context_is_proper(const secp256k1_context* ctx) { + return secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx); +} + void secp256k1_selftest(void) { if (!secp256k1_selftest_passes()) { secp256k1_callback_call(&default_error_callback, "self test failed"); @@ -171,6 +180,9 @@ void secp256k1_context_destroy(secp256k1_context* ctx) { } void secp256k1_context_set_illegal_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) { + /* We compare pointers instead of checking secp256k1_context_is_proper() here + because setting callbacks is allowed on *copies* of the static context: + it's harmless and makes testing easier. */ ARG_CHECK_NO_RETURN(ctx != secp256k1_context_static); if (fun == NULL) { fun = secp256k1_default_illegal_callback_fn; @@ -180,6 +192,9 @@ void secp256k1_context_set_illegal_callback(secp256k1_context* ctx, void (*fun)( } void secp256k1_context_set_error_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) { + /* We compare pointers instead of checking secp256k1_context_is_proper() here + because setting callbacks is allowed on *copies* of the static context: + it's harmless and makes testing easier. */ ARG_CHECK_NO_RETURN(ctx != secp256k1_context_static); if (fun == NULL) { fun = secp256k1_default_error_callback_fn;