From 586965c9cdf63170ccc3713ebf87201c46d3428c Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Tue, 02 May 2023 20:27:14 -0400
Subject: ustar: Fill header with zeroes before populating

---
(limited to 'src')

diff --git a/src/ustar.c b/src/ustar.c
index 13e7621..8c31f7a 100644
--- a/src/ustar.c
+++ b/src/ustar.c
@@ -271,11 +271,12 @@ opkg_opk_ustar_write_header(struct opkg_opk_ustar *ustar,
 		uid_t uid, const char *uname, gid_t gid, const char *gname,
 		uint64_t size, int64_t mtime, char type, const char *linkname)
 {
-	size_t    linkname_len;
 	uint32_t  chksum;
 	size_t    i;
 	char     *header_uc;
 
+	memset(&ustar->header, 0, sizeof(ustar->header));
+
 	if (opkg_opk_dirent_name_prefix(dirent,
 				ustar->header.name,
 				sizeof(ustar->header.name),
@@ -296,6 +297,8 @@ opkg_opk_ustar_write_header(struct opkg_opk_ustar *ustar,
 			break;
 		case 'l':  /* Symbolic link */
 			*ustar->header.typeflag = '2';
+			strncpy(ustar->header.linkname, linkname,
+					sizeof(ustar->header.linkname));
 			break;
 		case 'c':  /* Character special file */
 			*ustar->header.typeflag = '3';
@@ -312,14 +315,6 @@ opkg_opk_ustar_write_header(struct opkg_opk_ustar *ustar,
 		default:
 			return OPKG_OPK_ERROR;  /* Unsupported */
 	}
-	if (*ustar->header.typeflag == '2') {
-		linkname_len = strlen(linkname);
-		memcpy(ustar->header.linkname, linkname, linkname_len);
-	} else {
-		linkname_len = 0;
-	}
-	memset(ustar->header.linkname, 0,
-			sizeof(ustar->header.linkname) - linkname_len);
 
 	strcpy(ustar->header.magic, "ustar");
 	memcpy(ustar->header.version, "00", 2);
--
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