From: Michael Tremer <michael.tremer@ipfire.org>
Date: Sun, 7 Mar 2021 23:56:59 +0000 (+0000)
Subject: archive: Compute BLAKE2 checksum when extracting files
X-Git-Tag: 0.9.28~1285^2~611
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ab0465c13a8f0cdda3a3ea9cdff6f715f82e67f;p=pakfire.git

archive: Compute BLAKE2 checksum when extracting files

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/libpakfire/archive.c b/src/libpakfire/archive.c
index b41d76918..eb05acb3e 100644
--- a/src/libpakfire/archive.c
+++ b/src/libpakfire/archive.c
@@ -617,35 +617,76 @@ PAKFIRE_EXPORT char* pakfire_archive_get(PakfireArchive archive, const char* nam
 	return pakfire_parser_get(archive->parser, namespace, key);
 }
 
-static int archive_copy_data(Pakfire pakfire, struct archive* in, struct archive* out) {
-	int r;
-	const void* buff;
+static int archive_copy_data(Pakfire pakfire, struct archive* in, struct archive* out,
+		char** hexdigest) {
+	EVP_MD_CTX* mdctx = EVP_MD_CTX_new();
+
+	// Initialize digest
+	int r = EVP_DigestInit_ex(mdctx, EVP_blake2s256(), NULL);
+	if (r != 1) {
+		ERROR(pakfire, "Could not setup digest function: %s\n",
+			ERR_error_string(ERR_get_error(), NULL));
+		r = 1;
+		goto ERROR;
+	}
 
+	const void* buffer;
 	size_t size;
 	off_t offset;
 
 	for (;;) {
-		r = archive_read_data_block(in, &buff, &size, &offset);
+		// Read a block of data
+		r = archive_read_data_block(in, &buffer, &size, &offset);
 		if (r == ARCHIVE_EOF)
 			break;
 
 		if (r != ARCHIVE_OK) {
 			ERROR(pakfire, "Could not read data from archive: %s\n",
 				archive_error_string(in));
+			goto ERROR;
+		}
 
-			return r;
+		// Update digest
+		r = EVP_DigestUpdate(mdctx, buffer, size);
+		if (r != 1) {
+			ERROR(pakfire, "EVP_DigestUpdate failed: %s\n",
+				ERR_error_string(ERR_get_error(), NULL));
+			r = 1;
+			goto ERROR;
 		}
 
-		r = archive_write_data_block(out, buff, size, offset);
+		// Write the data
+		r = archive_write_data_block(out, buffer, size, offset);
 		if (r != ARCHIVE_OK) {
 			ERROR(pakfire, "Could not write data to disk: %s\n",
 				archive_error_string(out));
-
-			return r;
+			goto ERROR;
 		}
 	}
 
-	return 0;
+	char digest[EVP_MAX_MD_SIZE];
+	size_t digest_length;
+
+	// Finalize the digest
+	r = EVP_DigestFinal_ex(mdctx, (unsigned char*)digest, (unsigned int*)&digest_length);
+	if (r != 1) {
+		ERROR(pakfire, "%s\n", ERR_error_string(ERR_get_error(), NULL));
+		goto ERROR;
+	}
+
+	// Convert to hex
+	*hexdigest = pakfire_hexlify(digest, digest_length);
+
+	DEBUG(pakfire, "Computed digest of %zu bytes: %s\n", digest_length, *hexdigest);
+
+	// Success
+	r = 0;
+
+ERROR:
+	if (mdctx)
+		EVP_MD_CTX_free(mdctx);
+
+	return r;
 }
 
 static int archive_extract(Pakfire pakfire, struct archive* a, const char* prefix) {
@@ -698,6 +739,8 @@ static int archive_extract(Pakfire pakfire, struct archive* a, const char* prefi
 			free(h);
 		}
 
+		char* hexdigest = NULL;
+
 		// Create file
 		r = archive_write_header(ext, entry);
 		if (r != ARCHIVE_OK) {
@@ -708,7 +751,7 @@ static int archive_extract(Pakfire pakfire, struct archive* a, const char* prefi
 
 		// Copy payload
 		if (size > 0) {
-			r = archive_copy_data(pakfire, a, ext);
+			r = archive_copy_data(pakfire, a, ext, &hexdigest);
 			if (r != ARCHIVE_OK)
 				break;
 		}
@@ -735,6 +778,9 @@ static int archive_extract(Pakfire pakfire, struct archive* a, const char* prefi
 				break;
 		}
 
+		if (hexdigest)
+			free(hexdigest);
+
 		if (r != ARCHIVE_OK)
 			break;
 	}
diff --git a/src/libpakfire/include/pakfire/util.h b/src/libpakfire/include/pakfire/util.h
index c4ef1bf3f..2deb4faad 100644
--- a/src/libpakfire/include/pakfire/util.h
+++ b/src/libpakfire/include/pakfire/util.h
@@ -61,6 +61,8 @@ char* pakfire_generate_uuid();
 int pakfire_string_endswith(const char* s, const char* suffix);
 char* pakfire_lstrip(const char* s);
 
+char* pakfire_hexlify(const char* digest, const size_t length);
+
 #endif
 
 #endif /* PAKFIRE_UTIL_H */
diff --git a/src/libpakfire/util.c b/src/libpakfire/util.c
index 9f0b054ac..e4daba7f3 100644
--- a/src/libpakfire/util.c
+++ b/src/libpakfire/util.c
@@ -476,3 +476,23 @@ PAKFIRE_EXPORT char* pakfire_generate_uuid() {
 
 	return ret;
 }
+
+char* pakfire_hexlify(const char* digest, const size_t length) {
+	const char* hexdigits = "0123456789abcdef";
+
+	char* s = malloc((length * 2) + 1);
+	if (!s)
+		return NULL;
+
+	for (unsigned int i = 0, j = 0; i < length; i++) {
+		char b = digest[i];
+
+		s[j++] = hexdigits[(b >> 4) & 0xf];
+		s[j++] = hexdigits[(b & 0x0f)];
+	}
+
+	// Terminate result
+	s[length * 2] = '\0';
+
+	return s;
+}