From 6ed0c8c5c5ea4938988151c84385ebfb8b2601b6 Mon Sep 17 00:00:00 2001
From: Duncaen <mail@duncano.de>
Date: Sun, 7 Jul 2019 14:09:49 +0200
Subject: [PATCH] lib/verifysig.c: add xbps_verify_signature to verify
 signature against digest

---
 include/xbps.h.in | 13 +++++++++++++
 lib/verifysig.c   | 44 +++++++++++++++++++++++++++-----------------
 2 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/include/xbps.h.in b/include/xbps.h.in
index 02990291..5adec1a6 100644
--- a/include/xbps.h.in
+++ b/include/xbps.h.in
@@ -1866,6 +1866,19 @@ unsigned char *xbps_file_hash_raw(const char *file);
  */
 int xbps_file_hash_check(const char *file, const char *sha256);
 
+/**
+ * Verifies the RSA signature \a sigfile against \a digest with the
+ * RSA public-key associated in \a repo.
+ *
+ * @param[in] repo Repository to use with the RSA public key associated.
+ * @param[in] sigfile The signature file name used to verify \a digest.
+ * @param[in] digest The digest to verify.
+ *
+ * @return True if the signature is valid, false otherwise.
+ */
+bool xbps_verify_signature(struct xbps_repo *repo, const char *sigfile,
+		unsigned char *digest);
+
 /**
  * Verifies the RSA signature of \a fname with the RSA public-key associated
  * in \a repo.
diff --git a/lib/verifysig.c b/lib/verifysig.c
index a48bb4a7..58729a37 100644
--- a/lib/verifysig.c
+++ b/lib/verifysig.c
@@ -72,14 +72,15 @@ rsa_verify_hash(struct xbps_repo *repo, xbps_data_t pubkey,
 }
 
 bool
-xbps_verify_file_signature(struct xbps_repo *repo, const char *fname)
+xbps_verify_signature(struct xbps_repo *repo, const char *sigfile,
+		unsigned char *digest)
 {
 	xbps_dictionary_t repokeyd = NULL;
 	xbps_data_t pubkey;
 	char *hexfp = NULL;
-	unsigned char *digest = NULL, *sig_buf = NULL;
+	unsigned char *sig_buf = NULL;
 	size_t sigbuflen, sigfilelen;
-	char *rkeyfile = NULL, *sig = NULL;
+	char *rkeyfile = NULL;
 	bool val = false;
 
 	if (!xbps_dictionary_count(repo->idxmeta)) {
@@ -92,6 +93,7 @@ xbps_verify_file_signature(struct xbps_repo *repo, const char *fname)
 		xbps_dbg_printf(repo->xhp, "%s: incomplete signed repo, missing hexfp obj\n", repo->uri);
 		return false;
 	}
+
 	/*
 	 * Prepare repository RSA public key to verify fname signature.
 	 */
@@ -107,16 +109,9 @@ xbps_verify_file_signature(struct xbps_repo *repo, const char *fname)
 	if (xbps_object_type(pubkey) != XBPS_TYPE_DATA)
 		goto out;
 
-	/*
-	 * Prepare fname and signature data buffers.
-	 */
-	if (!(digest = xbps_file_hash_raw(fname))) {
-		xbps_dbg_printf(repo->xhp, "can't open file %s: %s\n", fname, strerror(errno));
-		goto out;
-	}
-	sig = xbps_xasprintf("%s.sig", fname);
-	if (!xbps_mmap_file(sig, (void *)&sig_buf, &sigbuflen, &sigfilelen)) {
-		xbps_dbg_printf(repo->xhp, "can't open signature file %s: %s\n", sig, strerror(errno));
+	if (!xbps_mmap_file(sigfile, (void *)&sig_buf, &sigbuflen, &sigfilelen)) {
+		xbps_dbg_printf(repo->xhp, "can't open signature file %s: %s\n",
+		    sigfile, strerror(errno));
 		goto out;
 	}
 	/*
@@ -130,14 +125,29 @@ out:
 		free(hexfp);
 	if (rkeyfile)
 		free(rkeyfile);
-	if (digest)
-		free(digest);
 	if (sig_buf)
 		(void)munmap(sig_buf, sigbuflen);
-	if (sig)
-		free(sig);
 	if (repokeyd)
 		xbps_object_release(repokeyd);
 
 	return val;
 }
+
+bool
+xbps_verify_file_signature(struct xbps_repo *repo, const char *fname)
+{
+	char sig[PATH_MAX];
+	unsigned char *digest = NULL;
+	bool val = false;
+
+	if (!(digest = xbps_file_hash_raw(fname))) {
+		xbps_dbg_printf(repo->xhp, "can't open file %s: %s\n", fname, strerror(errno));
+		return false;
+	}
+
+	snprintf(sig, sizeof sig, "%s.sig", fname);
+	val = xbps_verify_signature(repo, sig, digest);
+
+	free(digest);
+	return val;
+}