libxbps: ABI/API break due to hash function changes

2020-02-10 01:54:52 +01:00
parent aa4d726dca
commit 0d90534236
18 changed files with 141 additions and 118 deletions
--- a/bin/xbps-create/main.c
+++ b/bin/xbps-create/main.c
@@ -55,7 +55,8 @@ struct xentry {
 	TAILQ_ENTRY(xentry) entries;
 	uint64_t mtime;
 	uint64_t size;
-	char *file, *type, *target, *hash;
+	char *file, *type, *target;
+	char sha256[XBPS_SHA256_SIZE];
 	ino_t inode;
 };

@@ -317,6 +318,7 @@ ftw_cb(const char *fpath, const struct stat *sb, const struct dirent *dir UNUSED
 	xbps_dictionary_t fileinfo = NULL;
 	const char *filep = NULL;
 	char *buf, *p, *p2, *dname;
+	char sha256[XBPS_SHA256_SIZE];
 	ssize_t r;

 	/* Ignore metadata files generated by xbps-src and destdir */
@@ -480,12 +482,9 @@ ftw_cb(const char *fpath, const struct stat *sb, const struct dirent *dir UNUSED
 		}

 		assert(xe->type);
-		if ((p = xbps_file_hash(fpath)) == NULL)
-			die("failed to process hash for %s:", fpath);
-		xbps_dictionary_set_cstring(fileinfo, "sha256", p);
-		free(p);
-		if ((xe->hash = xbps_file_hash(fpath)) == NULL)
+		if (!xbps_file_sha256(xe->sha256, sizeof sha256, fpath))
 			die("failed to process hash for %s:", fpath);
+		xbps_dictionary_set_cstring(fileinfo, "sha256", xe->sha256);

 		xbps_dictionary_set_uint64(fileinfo, "inode", sb->st_ino);
 		xe->inode = sb->st_ino;
@@ -607,8 +606,8 @@ process_xentry(const char *key, const char *mutable_files)
 		xbps_dictionary_set_cstring(d, "file", p);
 		if (xe->target)
 			xbps_dictionary_set_cstring(d, "target", xe->target);
-		if (xe->hash)
-			xbps_dictionary_set_cstring(d, "sha256", xe->hash);
+		if (*xe->sha256)
+			xbps_dictionary_set_cstring(d, "sha256", xe->sha256);
 		if (xe->mtime)
 			xbps_dictionary_set_uint64(d, "mtime", xe->mtime);
 		if (xe->size)
--- a/bin/xbps-digest/main.c
+++ b/bin/xbps-digest/main.c
@@ -53,7 +53,7 @@ int
 main(int argc, char **argv)
 {
 	int c;
-	char *hash = NULL;
+	char sha256[XBPS_SHA256_SIZE];
 	const char *mode = NULL, *progname = argv[0];
 	const struct option longopts[] = {
 		{ NULL, 0, NULL, 0 }
@@ -84,23 +84,19 @@ main(int argc, char **argv)
 	}

 	if (argc < 1) {
-		hash = xbps_file_hash("/dev/stdin");
-		if (hash == NULL)
+		if (!xbps_file_sha256(sha256, sizeof sha256, "/dev/stdin"))
 			exit(EXIT_FAILURE);

-		printf("%s\n", hash);
-		free(hash);
+		printf("%s\n", sha256);
 	} else {
 		for (int i = 0; i < argc; i++) {
-			hash = xbps_file_hash(argv[i]);
-			if (hash == NULL) {
+			if (!xbps_file_sha256(sha256, sizeof sha256, argv[i])) {
 				fprintf(stderr,
 				    "%s: couldn't get hash for %s (%s)\n",
 				progname, argv[i], strerror(errno));
 				exit(EXIT_FAILURE);
 			}
-			printf("%s\n", hash);
-			free(hash);
+			printf("%s\n", sha256);
 		}
 	}
 	exit(EXIT_SUCCESS);
--- a/bin/xbps-fetch/main.c
+++ b/bin/xbps-fetch/main.c
@@ -138,13 +138,13 @@ main(int argc, char **argv)
 	}

 	for (int i = 0; i < argc; i++) {
-		unsigned char *digest = NULL;
+		unsigned char digest[XBPS_SHA256_DIGEST_SIZE];

 		if (i > 0 || !filename)
 			filename = fname(argv[i]);

 		if (shasum) {
-			rv = xbps_fetch_file_dest_digest(&xh, argv[i], filename, verbose ? "v" : "", &digest);
+			rv = xbps_fetch_file_dest_sha256(&xh, argv[i], filename, verbose ? "v" : "", digest, sizeof digest);
 		} else {
 			rv = xbps_fetch_file_dest(&xh, argv[i], filename, verbose ? "v" : "");
 		}
@@ -153,15 +153,19 @@ main(int argc, char **argv)
 			fprintf(stderr, "%s: %s\n", argv[i], xbps_fetch_error_string());
 		} else if (rv == 0) {
 			fprintf(stderr, "%s: file is identical with remote.\n", argv[i]);
-			if (shasum)
-				digest = xbps_file_hash_raw(filename);
+			if (shasum) {
+				if (!xbps_file_sha256_raw(digest, sizeof digest, filename)) {
+					xbps_error_printf("%s: failed to hash libxbps: %s: %s\n",
+						progname, filename, strerror(rv));
+					*digest = '\0';
+				}
+			}
 		} else {
 			rv = 0;
 		}
-		if (digest != NULL) {
+		if (*digest) {
 			print_digest(digest, SHA256_DIGEST_LENGTH);
 			printf("  %s\n", filename);
-			free(digest);
 		}
 	}

--- a/bin/xbps-pkgdb/check.c
+++ b/bin/xbps-pkgdb/check.c
@@ -102,7 +102,7 @@ check_pkg_integrity(struct xbps_handle *xhp,
 			free(buf);
 			return -1;
 		}
-		rv = xbps_file_hash_check(buf, sha256);
+		rv = xbps_file_sha256_check(buf, sha256);
 		free(buf);
 		if (rv == ENOENT) {
 			xbps_dictionary_remove(opkgd, "metafile-sha256");
--- a/bin/xbps-pkgdb/check_pkg_files.c
+++ b/bin/xbps-pkgdb/check_pkg_files.c
@@ -99,9 +99,9 @@ check_pkg_files(struct xbps_handle *xhp, const char *pkgname, void *arg)
 			if (xhp->noextract && xbps_patterns_match(xhp->noextract, file))
 				continue;
 			path = xbps_xasprintf("%s/%s", xhp->rootdir, file);
-                        xbps_dictionary_get_cstring_nocopy(obj,
-                            "sha256", &sha256);
-			rv = xbps_file_hash_check(path, sha256);
+			xbps_dictionary_get_cstring_nocopy(obj,
+				"sha256", &sha256);
+			rv = xbps_file_sha256_check(path, sha256);
 			switch (rv) {
 			case 0:
 				if (check_file_mtime(obj, pkgname, path)) {
--- a/bin/xbps-remove/clean-cache.c
+++ b/bin/xbps-remove/clean-cache.c
@@ -72,7 +72,7 @@ cleaner_cb(struct xbps_handle *xhp, xbps_object_t obj,
 	if (repo_pkgd) {
 		xbps_dictionary_get_cstring_nocopy(repo_pkgd,
 		    "filename-sha256", &rsha256);
-		if (xbps_file_hash_check(binpkg, rsha256) == 0) {
+		if (xbps_file_sha256_check(binpkg, rsha256) == 0) {
 			/* hash matched */
 			return 0;
 		}
--- a/bin/xbps-rindex/index-add.c
+++ b/bin/xbps-rindex/index-add.c
@@ -252,7 +252,8 @@ index_add(struct xbps_handle *xhp, int args, int argmax, char **argv, bool force
 	 */
 	for (int i = args; i < argmax; i++) {
 		const char *arch = NULL, *pkg = argv[i];
-		char *sha256 = NULL, *pkgver = NULL;
+		char *pkgver = NULL;
+		char sha256[XBPS_SHA256_SIZE];
 		char pkgname[XBPS_NAME_SIZE];

 		assert(pkg);
@@ -331,7 +332,7 @@ index_add(struct xbps_handle *xhp, int args, int argmax, char **argv, bool force
 		 * 	- filename-size
 		 * 	- filename-sha256
 		 */
-		if ((sha256 = xbps_file_hash(pkg)) == NULL) {
+		if (!xbps_file_sha256(sha256, sizeof sha256, pkg)) {
 			xbps_object_release(binpkgd);
 			free(pkgver);
 			rv = EINVAL;
@@ -339,12 +340,10 @@ index_add(struct xbps_handle *xhp, int args, int argmax, char **argv, bool force
 		}
 		if (!xbps_dictionary_set_cstring(binpkgd, "filename-sha256", sha256)) {
 			xbps_object_release(binpkgd);
-			free(sha256);
 			free(pkgver);
 			rv = EINVAL;
 			goto out;
 		}
-		free(sha256);
 		if (stat(pkg, &st) == -1) {
 			xbps_object_release(binpkgd);
 			free(pkgver);
--- a/bin/xbps-rindex/index-clean.c
+++ b/bin/xbps-rindex/index-clean.c
@@ -77,7 +77,7 @@ idx_cleaner_cb(struct xbps_handle *xhp,
 		 */
 		xbps_dictionary_get_cstring_nocopy(obj,
 				"filename-sha256", &sha256);
-		if (xbps_file_hash_check(filen, sha256) != 0) {
+		if (xbps_file_sha256_check(filen, sha256) != 0) {
 			if (!xbps_pkg_name(pkgname, sizeof(pkgname), pkgver))
 				goto out;
 			xbps_dictionary_remove(dest, pkgname);
--- a/bin/xbps-rindex/sign.c
+++ b/bin/xbps-rindex/sign.c
@@ -97,25 +97,26 @@ static bool
 rsa_sign_file(RSA *rsa, const char *file,
 	 unsigned char **sigret, unsigned int *siglen)
 {
-	unsigned char *sha256;
+	unsigned char digest[XBPS_SHA256_DIGEST_SIZE];

-	sha256 = xbps_file_hash_raw(file);
-	if(!sha256)
+	if (!xbps_file_sha256_raw(digest, sizeof digest, file))
 		return false;

 	if ((*sigret = calloc(1, RSA_size(rsa) + 1)) == NULL) {
-		free(sha256);
 		return false;
 	}

-	if (!RSA_sign(NID_sha1, sha256, SHA256_DIGEST_LENGTH,
+	/*
+	 * XXX: NID_sha1 is wrong, doesn't make it any weaker
+	 * but the ASN1 is wrong, OpenSSL/LibreSSL doesn't care.
+	 * Other implementations like golang fail because of this.
+	 */
+	if (!RSA_sign(NID_sha1, digest, XBPS_SHA256_DIGEST_SIZE,
 				*sigret, siglen, rsa)) {
-		free(sha256);
 		free(*sigret);
 		return false;
 	}

-	free(sha256);
 	return true;
 }

--- a/bin/xbps-uhelper/main.c
+++ b/bin/xbps-uhelper/main.c
@@ -285,19 +285,20 @@ main(int argc, char **argv)

 		printf("%s\n", XBPS_SYSDEFCONF_PATH);
 	} else if (strcmp(argv[0], "digest") == 0) {
+		char sha256[XBPS_SHA256_SIZE];
+
 		/* Prints SHA256 hashes for specified files */
 		if (argc < 2)
 			usage();

 		for (int i = 1; i < argc; i++) {
-			filename = xbps_file_hash(argv[i]);
-			if (filename == NULL) {
+			if (!xbps_file_sha256(sha256, sizeof sha256, argv[i])) {
 				fprintf(stderr,
 				    "E: couldn't get hash for %s (%s)\n",
 				    argv[i], strerror(errno));
 				exit(EXIT_FAILURE);
 			}
-			printf("%s\n", filename);
+			printf("%s\n", sha256);
 		}
 	} else if (strcmp(argv[0], "fetch") == 0) {
 		/* Fetch a file from specified URL */
--- a/include/xbps.h.in
+++ b/include/xbps.h.in
@@ -51,7 +51,7 @@
 *
 * This header documents the full API for the XBPS Library.
 */
-#define XBPS_API_VERSION	"20200208"
+#define XBPS_API_VERSION	"20200210"

 #ifndef XBPS_VERSION
 #define XBPS_VERSION		"UNSET"
@@ -258,6 +258,9 @@
 */
 #define XBPS_FETCH_TIMEOUT		30

+#define XBPS_SHA256_DIGEST_SIZE 32
+#define XBPS_SHA256_SIZE 64+1
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -763,8 +766,8 @@ int xbps_fetch_file(struct xbps_handle *xhp, const char *uri,
 * @return -1 on error, 0 if not downloaded (because local/remote size/mtime
 * do not match) and 1 if downloaded successfully.
 **/
-int xbps_fetch_file_digest(struct xbps_handle *xhp, const char *uri,
-		    const char *flags, unsigned char **digestp);
+int xbps_fetch_file_sha256(struct xbps_handle *xhp, const char *uri,
+		    const char *flags, unsigned char *digest, size_t digestlen);

 /**
 * Download a file from a remote URL to current working directory,
@@ -794,8 +797,9 @@ int xbps_fetch_file_dest(struct xbps_handle *xhp, const char *uri,
 * @return -1 on error, 0 if not downloaded (because local/remote size/mtime
 * do not match) and 1 if downloaded successfully.
 **/
-int xbps_fetch_file_dest_digest(struct xbps_handle *xhp, const char *uri,
-		    const char *filename, const char *flags, unsigned char **digestp);
+int xbps_fetch_file_dest_sha256(struct xbps_handle *xhp, const char *uri,
+		    const char *filename, const char *flags,
+			unsigned char *digest, size_t digestlen);

 /**
 * Returns last error string reported by xbps_fetch_file().
@@ -1859,7 +1863,7 @@ bool xbps_mmap_file(const char *file, void **mmf, size_t *mmflen, size_t *filele
 * is set appropiately. The pointer should be free(3)d when it's no
 * longer needed.
 */
-char *xbps_file_hash(const char *file);
+bool xbps_file_sha256(char *dst, size_t dstlen, const char *file);

 /**
 * Returns a raw byte buffer with the sha256 hash for the file specified
@@ -1870,7 +1874,7 @@ char *xbps_file_hash(const char *file);
 * is set appropiately. The pointer should be free(3)d when it's no
 * longer needed.
 */
-unsigned char *xbps_file_hash_raw(const char *file);
+bool xbps_file_sha256_raw(unsigned char *dst, size_t dstlen, const char *file);

 /**
 * Compares the sha256 hash of the file \a file with the sha256
@@ -1882,7 +1886,7 @@ unsigned char *xbps_file_hash_raw(const char *file);
 * @return 0 if \a file and \a sha256 have the same hash, ERANGE
 * if it differs, or any other errno value on error.
 */
-int xbps_file_hash_check(const char *file, const char *sha256);
+int xbps_file_sha256_check(const char *file, const char *sha256);

 /**
 * Verifies the RSA signature \a sigfile against \a digest with the
--- a/lib/download.c
+++ b/lib/download.c
@@ -93,7 +93,7 @@ xbps_fetch_error_string(void)
 }

 int
-xbps_fetch_file_dest_digest(struct xbps_handle *xhp, const char *uri, const char *filename, const char *flags, unsigned char **digestp)
+xbps_fetch_file_dest_sha256(struct xbps_handle *xhp, const char *uri, const char *filename, const char *flags, unsigned char *digest, size_t digestlen)
 {
 	struct stat st, st_tmpfile, *stp;
 	struct url *url = NULL;
@@ -106,16 +106,13 @@ xbps_fetch_file_dest_digest(struct xbps_handle *xhp, const char *uri, const char
 	char fetch_flags[8];
 	int fd = -1, rv = 0;
 	bool refetch = false, restart = false;
-	unsigned char *digest = NULL;
 	SHA256_CTX sha256;

 	assert(xhp);
 	assert(uri);

-	if (digestp) {
-		digest = malloc(SHA256_DIGEST_LENGTH);
-		if (!digest)
-			return -1;
+	if (digest) {
+		assert(digestlen != XBPS_SHA256_DIGEST_SIZE);
 		SHA256_Init(&sha256);
 	}

@@ -317,10 +314,8 @@ rename_file:
 	}
 	rv = 1;

-	if (digest) {
+	if (digest)
 		SHA256_Final(digest, &sha256);
-		*digestp = digest;
-	}

 fetch_file_out:
 	if (fio != NULL)
@@ -339,12 +334,12 @@ int
 xbps_fetch_file_dest(struct xbps_handle *xhp, const char *uri,
 		const char *filename, const char *flags)
 {
-	return xbps_fetch_file_dest_digest(xhp, uri, filename, flags, NULL);
+	return xbps_fetch_file_dest_sha256(xhp, uri, filename, flags, NULL, 0);
 }

 int
-xbps_fetch_file_digest(struct xbps_handle *xhp, const char *uri,
-		const char *flags, unsigned char **digestp)
+xbps_fetch_file_sha256(struct xbps_handle *xhp, const char *uri,
+		const char *flags, unsigned char *digest, size_t digestlen)
 {
 	const char *filename;
 	/*
@@ -354,11 +349,12 @@ xbps_fetch_file_digest(struct xbps_handle *xhp, const char *uri,
 		return -1;

 	filename++;
-	return xbps_fetch_file_dest_digest(xhp, uri, filename, flags, digestp);
+	return xbps_fetch_file_dest_sha256(xhp, uri, filename, flags,
+	    digest, digestlen);
 }

 int
 xbps_fetch_file(struct xbps_handle *xhp, const char *uri, const char *flags)
 {
-	return xbps_fetch_file_digest(xhp, uri, flags, NULL);
+	return xbps_fetch_file_sha256(xhp, uri, flags, NULL, 0);
 }
--- a/lib/package_config_files.c
+++ b/lib/package_config_files.c
@@ -69,7 +69,7 @@ xbps_entry_install_conf_file(struct xbps_handle *xhp,
 	xbps_object_t obj, obj2;
 	xbps_object_iterator_t iter, iter2;
 	const char *version = NULL, *cffile, *sha256_new = NULL;
-	char buf[PATH_MAX], *sha256_cur = NULL, *sha256_orig = NULL;
+	char buf[PATH_MAX], sha256_cur[XBPS_SHA256_SIZE], *sha256_orig = NULL;
 	int rv = 0;

 	assert(xbps_object_type(binpkg_filesd) == XBPS_TYPE_DICTIONARY);
@@ -139,9 +139,7 @@ xbps_entry_install_conf_file(struct xbps_handle *xhp,
 		if (strcmp(entry_pname, buf)) {
 			continue;
 		}
-		sha256_cur = xbps_file_hash(buf);
-		xbps_dictionary_get_cstring_nocopy(obj, "sha256", &sha256_new);
-		if (sha256_cur == NULL) {
+		if (!xbps_file_sha256(sha256_cur, sizeof sha256_cur, buf)) {
 			if (errno == ENOENT) {
 				/*
 				 * File not installed, install new one.
@@ -155,6 +153,7 @@ xbps_entry_install_conf_file(struct xbps_handle *xhp,
 				break;
 			}
 		}
+		xbps_dictionary_get_cstring_nocopy(obj, "sha256", &sha256_new);
 		/*
 		 * Orig = X, Curr = X, New = X
 		 *
@@ -232,15 +231,11 @@ xbps_entry_install_conf_file(struct xbps_handle *xhp,
 			rv = 1;
 			break;
 		}
-		free(sha256_cur);
-		sha256_cur = NULL;
 	}

 out:
 	if (sha256_orig)
 		free(sha256_orig);
-	if (sha256_cur)
-		free(sha256_cur);

 	xbps_object_iterator_release(iter);

--- a/lib/package_register.c
+++ b/lib/package_register.c
@@ -41,7 +41,8 @@ xbps_register_pkg(struct xbps_handle *xhp, xbps_dictionary_t pkgrd)
 	struct tm tm;
 	struct tm *tmp;
 	const char *pkgver;
-	char *buf, *sha256;
+	char sha256[XBPS_SHA256_SIZE];
+	char *buf;
 	int rv = 0;
 	bool autoinst = false;

@@ -104,9 +105,8 @@ xbps_register_pkg(struct xbps_handle *xhp, xbps_dictionary_t pkgrd)
 	 * Create a hash for the pkg's metafile if it exists.
 	 */
 	buf = xbps_xasprintf("%s/.%s-files.plist", xhp->metadir, pkgname);
-	if ((sha256 = xbps_file_hash(buf))) {
+	if (xbps_file_sha256(sha256, sizeof sha256, buf)) {
 		xbps_dictionary_set_cstring(pkgd, "metafile-sha256", sha256);
-		free(sha256);
 	}
 	free(buf);
 	/*
--- a/lib/transaction_fetch.c
+++ b/lib/transaction_fetch.c
@@ -79,7 +79,7 @@ verify_binpkg(struct xbps_handle *xhp, xbps_dictionary_t pkgd)
 		xbps_set_cb_state(xhp, XBPS_STATE_VERIFY, 0, pkgver,
 			"%s: verifying SHA256 hash...", pkgver);
 		xbps_dictionary_get_cstring_nocopy(pkgd, "filename-sha256", &sha256);
-		if ((rv = xbps_file_hash_check(binfile, sha256)) != 0) {
+		if ((rv = xbps_file_sha256_check(binfile, sha256)) != 0) {
 			xbps_set_cb_state(xhp, XBPS_STATE_VERIFY_FAIL, rv, pkgver,
 				"%s: SHA256 hash is not valid: %s", pkgver, strerror(rv));
 			goto out;
@@ -98,7 +98,7 @@ download_binpkg(struct xbps_handle *xhp, xbps_dictionary_t repo_pkgd)
 	char buf[PATH_MAX];
 	char *sigsuffix;
 	const char *pkgver, *arch, *fetchstr, *repoloc;
-	unsigned char *digest = NULL;
+	unsigned char digest[XBPS_SHA256_DIGEST_SIZE] = {0};
 	int rv = 0;

 	xbps_dictionary_get_cstring_nocopy(repo_pkgd, "repository", &repoloc);
@@ -129,7 +129,8 @@ download_binpkg(struct xbps_handle *xhp, xbps_dictionary_t repo_pkgd)
 	xbps_set_cb_state(xhp, XBPS_STATE_DOWNLOAD, 0, pkgver,
 		"Downloading `%s' package (from `%s')...", pkgver, repoloc);

-	if ((rv = xbps_fetch_file_digest(xhp, buf, NULL, &digest)) == -1) {
+	if ((rv = xbps_fetch_file_sha256(xhp, buf, NULL, digest,
+	    sizeof digest)) == -1) {
 		rv = fetchLastErrCode ? fetchLastErrCode : errno;
 		fetchstr = xbps_fetch_error_string();
 		xbps_set_cb_state(xhp, XBPS_STATE_DOWNLOAD_FAIL, rv,
@@ -156,7 +157,7 @@ download_binpkg(struct xbps_handle *xhp, xbps_dictionary_t repo_pkgd)
 	 * If digest is not set, binary package was not downloaded,
 	 * i.e. 304 not modified, verify by file instead.
 	 */
-	if (!digest) {
+	if (*digest) {
 		*sigsuffix = '\0';
 		if (!xbps_verify_file_signature(repo, buf)) {
 			rv = EPERM;
@@ -175,7 +176,6 @@ download_binpkg(struct xbps_handle *xhp, xbps_dictionary_t repo_pkgd)
 			*sigsuffix = '\0';
 			(void)remove(buf);
 		}
-		free(digest);
 	}

 	if (rv == EPERM) {
--- a/lib/transaction_files.c
+++ b/lib/transaction_files.c
@@ -75,6 +75,7 @@ itemhash(const char *file)

 	assert(file);

+	/* XXX: runtime error: left shift of negative value -1581911230 */
 	for (i = 0; file[i]; ++i)
 		hv = (hv << 5) ^ (hv >> 23) ^ file[i];

@@ -321,7 +322,7 @@ collect_obsoletes(struct xbps_handle *xhp)
 		 * Skip unexisting files and keep files with hash mismatch.
 		 */
 		if (item->old.sha256) {
-			rv = xbps_file_hash_check(item->file, item->old.sha256);
+			rv = xbps_file_sha256_check(item->file, item->old.sha256);
 			switch (rv) {
 			case 0:
 				/* hash matches, we can safely delete and/or overwrite it */
--- a/lib/util_hash.c
+++ b/lib/util_hash.c
@@ -108,65 +108,93 @@ xbps_mmap_file(const char *file, void **mmf, size_t *mmflen, size_t *filelen)
 	return true;
 }

-unsigned char *
-xbps_file_hash_raw(const char *file)
+bool
+xbps_file_sha256_raw(unsigned char *dst, size_t dstlen, const char *file)
 {
 	int fd;
 	ssize_t len;
-	unsigned char *digest, buf[65536];
+	char buf[65536];
 	SHA256_CTX sha256;

+	assert(dstlen == SHA256_DIGEST_LENGTH);
+
 	if ((fd = open(file, O_RDONLY)) < 0)
-		return NULL;
-	digest = malloc(SHA256_DIGEST_LENGTH);
-	assert(digest);
+		return false;
+
 	SHA256_Init(&sha256);
+
 	while ((len = read(fd, buf, sizeof(buf))) > 0)
 		SHA256_Update(&sha256, buf, len);
-	if(len < 0) {
-		free(digest);
-		return NULL;
-	}
-	SHA256_Final(digest, &sha256);
+
 	(void)close(fd);

-	return digest;
+	if(len == -1)
+		return false;
+
+	SHA256_Final(dst, &sha256);
+
+	return true;
 }

-char *
-xbps_file_hash(const char *file)
+bool
+xbps_file_sha256(char *dst, size_t dstlen, const char *file)
 {
-	char *hash;
-	unsigned char *digest;
+	unsigned char digest[XBPS_SHA256_DIGEST_SIZE];

-	if (!(digest = xbps_file_hash_raw(file)))
-		return NULL;
+	assert(dstlen == XBPS_SHA256_SIZE);

-	hash = malloc(SHA256_DIGEST_LENGTH * 2 + 1);
-	assert(hash);
-	digest2string(digest, hash, SHA256_DIGEST_LENGTH);
-	free(digest);
+	if (!xbps_file_sha256_raw(digest, sizeof digest, file))
+		return false;

-	return hash;
+	digest2string(digest, dst, XBPS_SHA256_DIGEST_SIZE);
+
+	return true;
+}
+
+static bool
+sha256_digest_compare(const char *sha256, size_t shalen,
+		const unsigned char *digest, size_t digestlen)
+{
+	assert(digestlen == XBPS_SHA256_DIGEST_SIZE);
+	assert(shalen == XBPS_SHA256_SIZE - 1);
+
+	if (shalen != XBPS_SHA256_SIZE -1)
+		return false;
+
+	for (; *sha256;) {
+		if (*digest / 16 < 10) {
+			if (*sha256++ != '0' + *digest / 16)
+				return false;
+		} else {
+			if (*sha256++ != 'a' + *digest / 16 - 10)
+				return false;
+		}
+		if (*digest % 16 < 10) {
+			if (*sha256++ != '0' + *digest % 16)
+				return false;
+		} else {
+			if (*sha256++ != 'a' + *digest % 16 - 10)
+				return false;
+		}
+		digest++;
+	}
+
+	return true;
 }

 int
-xbps_file_hash_check(const char *file, const char *sha256)
+xbps_file_sha256_check(const char *file, const char *sha256)
 {
-	char *res;
+	unsigned char digest[XBPS_SHA256_DIGEST_SIZE];

 	assert(file != NULL);
 	assert(sha256 != NULL);

-	res = xbps_file_hash(file);
-	if (res == NULL)
+	if (!xbps_file_sha256_raw(digest, sizeof digest, file))
 		return errno;

-	if (strcmp(sha256, res)) {
-		free(res);
+	if (!sha256_digest_compare(sha256, strlen(sha256), digest, sizeof digest))
 		return ERANGE;
-	}
-	free(res);

 	return 0;
 }
@@ -226,10 +254,10 @@ xbps_file_hash_check_dictionary(struct xbps_handle *xhp,
 	}

 	if (strcmp(xhp->rootdir, "/") == 0) {
-		rv = xbps_file_hash_check(file, sha256d);
+		rv = xbps_file_sha256_check(file, sha256d);
 	} else {
 		buf = xbps_xasprintf("%s/%s", xhp->rootdir, file);
-		rv = xbps_file_hash_check(buf, sha256d);
+		rv = xbps_file_sha256_check(buf, sha256d);
 		free(buf);
 	}
 	if (rv == 0)
--- a/lib/verifysig.c
+++ b/lib/verifysig.c
@@ -137,10 +137,10 @@ bool
 xbps_verify_file_signature(struct xbps_repo *repo, const char *fname)
 {
 	char sig[PATH_MAX];
-	unsigned char *digest = NULL;
+	unsigned char digest[XBPS_SHA256_DIGEST_SIZE];
 	bool val = false;

-	if (!(digest = xbps_file_hash_raw(fname))) {
+	if (!xbps_file_sha256_raw(digest, sizeof digest, fname)) {
 		xbps_dbg_printf(repo->xhp, "can't open file %s: %s\n", fname, strerror(errno));
 		return false;
 	}
@@ -148,6 +148,5 @@ xbps_verify_file_signature(struct xbps_repo *repo, const char *fname)
 	snprintf(sig, sizeof sig, "%s.sig", fname);
 	val = xbps_verify_signature(repo, sig, digest);

-	free(digest);
 	return val;
 }