From 28ea2b9718162761b5de617efa74ae2bd020acb2 Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Tue, 25 Apr 2023 05:35:44 -0400
Subject: ustar: Ensure listed linkname is NUL-terminated

Also simplify uname and gname copying.
---
diff --git a/configure.ac b/configure.ac
index f600715..38c62c2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -45,7 +45,7 @@ AC_CHECK_FUNCS(
 	[\
 		fclose feof ferror fopen fprintf fputs fread free fwrite \
 		localtime malloc memcmp memcpy memset printf puts snprintf \
-		sprintf strcmp strftime strlen strncpy strtol
+		sprintf strcmp strcpy strftime strlen strncpy strtol
 	],
 	[],
 	[funcs_missing=true])
diff --git a/src/ustar.c b/src/ustar.c
index 749af02..c759781 100644
--- a/src/ustar.c
+++ b/src/ustar.c
@@ -201,7 +201,9 @@ opkg_opk_ustar_list(struct opkg_opk_ustar *ustar,
 		case '2':  /* Symbolic link */
 			(*member)->type = 'l';
 			strncpy((*member)->linkname, ustar->header.linkname,
-					sizeof((*member)->linkname));
+					sizeof(ustar->header.linkname));
+			(*member)->linkname[sizeof((*member)->linkname) - 1] =
+				'\0';
 			break;
 		case '3':  /* Character special file */
 			(*member)->type = 'c';
@@ -220,10 +222,8 @@ opkg_opk_ustar_list(struct opkg_opk_ustar *ustar,
 			free(*member);
 			return OPKG_OPK_ERROR;  /* Unsupported */
 	}
-	strncpy((*member)->uname, ustar->header.uname,
-			sizeof((*member)->uname));
-	strncpy((*member)->gname, ustar->header.gname,
-			sizeof((*member)->gname));
+	strcpy((*member)->uname, ustar->header.uname);
+	strcpy((*member)->gname, ustar->header.gname);
 
 	/* Seek through data records until next header record. */
 	while (ustar->data_size_remaining > 0) {
diff --git a/src/ustar.h b/src/ustar.h
index 3495d38..220603a 100644
--- a/src/ustar.h
+++ b/src/ustar.h
@@ -35,7 +35,7 @@ struct opkg_opk_ustar_member {
 	uint64_t                      size;
 	int64_t                       mtime;
 	char                          type;
-	char                          linkname[100];
+	char                          linkname[101];
 	char                          uname    [32];
 	char                          gname    [32];
 	struct opkg_opk_ustar_member *next;
--
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