From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Sat, 19 Nov 2022 00:55:40 +0000 (+0100)
Subject: libblkid: add function blkid_probe_verify_csum_buf
X-Git-Tag: v2.39-rc1~410^2~4
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8c4084703dffd911e10b3b1ee2c2e60998bfc697;p=thirdparty%2Futil-linux.git

libblkid: add function blkid_probe_verify_csum_buf

This function is more convenient for checksums with longer digests.
---

diff --git a/libblkid/src/blkidP.h b/libblkid/src/blkidP.h
index 78b1cd1da6..43ceb9c981 100644
--- a/libblkid/src/blkidP.h
+++ b/libblkid/src/blkidP.h
@@ -517,6 +517,8 @@ extern int blkid_probe_set_magic(blkid_probe pr, uint64_t offset,
 
 extern int blkid_probe_verify_csum(blkid_probe pr, uint64_t csum, uint64_t expected)
 			__attribute__((nonnull));
+extern int blkid_probe_verify_csum_buf(blkid_probe pr, size_t n, const void *csum,
+		const void *expected) __attribute__((nonnull));
 
 extern void blkid_unparse_uuid(const unsigned char *uuid, char *str, size_t len)
 			__attribute__((nonnull));
diff --git a/libblkid/src/probe.c b/libblkid/src/probe.c
index f54c417785..203f0ae498 100644
--- a/libblkid/src/probe.c
+++ b/libblkid/src/probe.c
@@ -1780,16 +1780,34 @@ int blkid_probe_set_magic(blkid_probe pr, uint64_t offset,
 	return rc;
 }
 
-int blkid_probe_verify_csum(blkid_probe pr, uint64_t csum, uint64_t expected)
+static void blkid_probe_log_csum_mismatch(blkid_probe pr, size_t n, const void *csum,
+		const void *expected)
 {
-	if (csum != expected) {
+	char csum_hex[256];
+	char expected_hex[sizeof(csum_hex)];
+	int hex_size = min(sizeof(csum_hex), n * 2);
+
+	for (int i = 0; i < hex_size; i+=2) {
+		sprintf(&csum_hex[i], "%02X", ((const unsigned char *) csum)[i / 2]);
+		sprintf(&expected_hex[i], "%02X", ((const unsigned char *) expected)[i / 2]);
+	}
+
+	ul_debug(
+		"incorrect checksum for type %s,"
+		" got %*s, expected %*s",
+		blkid_probe_get_probername(pr),
+		hex_size, csum_hex, hex_size, expected_hex);
+}
+
+
+int blkid_probe_verify_csum_buf(blkid_probe pr, size_t n, const void *csum,
+		const void *expected)
+{
+	if (memcmp(csum, expected, n) != 0) {
 		struct blkid_chain *chn = blkid_probe_get_chain(pr);
 
-		DBG(LOWPROBE, ul_debug(
-				"incorrect checksum for type %s,"
-				" got %"PRIX64", expected %"PRIX64"",
-				blkid_probe_get_probername(pr),
-				csum, expected));
+		ON_DBG(LOWPROBE, blkid_probe_log_csum_mismatch(pr, n, csum, expected));
+
 		/*
 		 * Accept bad checksum if BLKID_SUBLKS_BADCSUM flags is set
 		 */
@@ -1805,6 +1823,11 @@ accept:
 	return 1;
 }
 
+int blkid_probe_verify_csum(blkid_probe pr, uint64_t csum, uint64_t expected)
+{
+	return blkid_probe_verify_csum_buf(pr, sizeof(csum), &csum, &expected);
+}
+
 /**
  * blkid_probe_get_devno:
  * @pr: probe