fuzz-tests: improve fuzz-bech32

tests/fuzz/corpora/fuzz-bech32/0498c0266912ccf9658ed070b58b07cbbe9dc98e

@@ -0,0 +1 @@
+z

tests/fuzz/corpora/fuzz-bech32/220b09b54b3b0be74c907671dea29683f5871fe0

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+
k

tests/fuzz/corpora/fuzz-bech32/46243041b61da83ae65396bdc148d6c8d5c1e15b

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+�'Q����

tests/fuzz/corpora/fuzz-bech32/7328edb2d8db8e77dc367f2835685fc58a7e18f6

@@ -0,0 +1 @@
+�0�
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tests/fuzz/corpora/fuzz-bech32/790e7a0245c67bc86878901df8d9d1c42177cb80

@@ -0,0 +1 @@
+(z):C>?R�

tests/fuzz/corpora/fuzz-bech32/9c7a8c0df01b7dddf4a6b5248228f67d0fdad99f

@@ -0,0 +1 @@
+(z):CJR�

tests/fuzz/corpora/fuzz-bech32/dfcc0463830763ade80df61a37efc4f843932160

@@ -0,0 +1 @@
+��

tests/fuzz/corpora/fuzz-bech32/fd7cd593a9afdf88105cf028a4b454479707cb16

@@ -0,0 +1 @@
+

tests/fuzz/fuzz-bech32.c

@@ -1,6 +1,6 @@
 #include "config.h"
 #include <assert.h>
-
+#include <common/utils.h>
 #include <common/bech32.h>
 #include <stdint.h>
 #include <string.h>
@@ -25,34 +25,45 @@ void run(const uint8_t *data, size_t size)
 	/* Buffer size is defined in each function's doc comment. */
 	benc = data[0] ? BECH32_ENCODING_BECH32 : BECH32_ENCODING_BECH32M;
 	bech32_str_cap = (size - 1) + strlen(hrp_inv) + 8;
-	bech32_str = malloc(bech32_str_cap);
+	bech32_str = tal_arr(tmpctx, char, bech32_str_cap);
 	if (bech32_encode(bech32_str, hrp_inv, data + 1, size - 1,
 			  bech32_str_cap, benc) == 1) {
-		hrp_out = malloc(strlen(bech32_str) - 6);
-		data_out = malloc(strlen(bech32_str) - 8);
+		hrp_out = tal_arr(tmpctx, char, strlen(bech32_str) - 6);
+		data_out = tal_arr(tmpctx, uint8_t, strlen(bech32_str) - 8);
 
 		benc_decoded = bech32_decode(hrp_out, data_out, &data_out_len,
 					     bech32_str, bech32_str_cap);
 		assert(benc_decoded == benc);
 		assert(strcmp(hrp_inv, hrp_out) == 0);
 		assert(data_out_len == size - 1);
 		assert(memcmp(data_out, data + 1, data_out_len) == 0);
-
-		free(hrp_out);
-		free(data_out);
 	}
-	free(bech32_str);
 
-	data_out = malloc(size);
+	/* Convert data to 5-bit values (0-31) */
+	u8 *five_bit_data = tal_dup_arr(tmpctx, u8, data, size, 0);
+	for (size_t i = 0; i < size; i++)
+		five_bit_data[i] &= 0x1F;
 
-	/* This is also used as part of sign and check message. */
-	data_out_len = 0;
-	bech32_convert_bits(data_out, &data_out_len, 8, data, size, 5, 1);
+	u8 *eight_bit_data = tal_arr(tmpctx, u8, size);
+	size_t eight_bit_len = 0;
+	/* Convert 5-to-8 without padding */
+	if (bech32_convert_bits(eight_bit_data, &eight_bit_len, 8,
+				five_bit_data, size, 5, 0)) {
+		u8 *five_bit_deconv = tal_arr(tmpctx, u8, size);
+		size_t five_bit_deconv_len = 0;
+		/* Convert 8-to-5 with padding */
+		if (bech32_convert_bits(five_bit_deconv, &five_bit_deconv_len, 5,
+					eight_bit_data, eight_bit_len, 8, 1)) {
+			assert(five_bit_deconv_len == size);
+			assert(memcmp(five_bit_data, five_bit_deconv, five_bit_deconv_len) == 0);
+		}
+	}
+
+	data_out = tal_arr(tmpctx, uint8_t, size);
 	data_out_len = 0;
-	bech32_convert_bits(data_out, &data_out_len, 8, data, size, 5, 0);
 
-	addr = malloc(73 + strlen(hrp_addr));
-	for (int wit_version = 0; wit_version < 2; ++wit_version) {
+	addr = tal_arr(tmpctx, char, 73 + strlen(hrp_addr));
+	for (int wit_version = 0; wit_version <= 16; ++wit_version) {
 		if (segwit_addr_encode(addr, hrp_addr, wit_version, data,
 				       size) == 0)
 			continue;
@@ -63,7 +74,6 @@ void run(const uint8_t *data, size_t size)
 		assert(data_out_len == size);
 		assert(memcmp(data_out, data, data_out_len) == 0);
 	}
-	free(addr);
 
-	free(data_out);
+	clean_tmpctx();
 }