From: Stephane Chazelas <stephane+gh@chazelas.org>
Date: Fri, 27 Dec 2024 23:20:16 +0000 (+0000)
Subject: tar: fix bug when -s/a/b/ used more than once with b flag (#2435)
X-Git-Tag: v3.8.0~94
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4d5106f2b5e48a34ec0e341974737252ed5aae84;p=thirdparty%2Flibarchive.git

tar: fix bug when -s/a/b/ used more than once with b flag (#2435)

When the -s/regexp/replacement/ option was used with the b flag more
than once, the result of the previous substitution was appended to the
previous subject instead of replacing it. Fixed it by making sure the
subject is made the empty string before the call to realloc_strcat().
That in effect makes it more like a realloc_strcpy(), but creating a new
realloc_strcpy() function for that one usage doesn't feel worth it.

Resolves Issue libarchive/libarchive#2414

Co-authored-by: Stephane Chazelas <stephane@chazelas.org>
---

diff --git a/tar/subst.c b/tar/subst.c
index 0194cc84b..5546b5f93 100644
--- a/tar/subst.c
+++ b/tar/subst.c
@@ -229,6 +229,7 @@ apply_substitution(struct bsdtar *bsdtar, const char *name, char **result,
 
 		if (rule->from_begin && *result) {
 			realloc_strcat(result, name);
+			if (buffer) buffer[0] = 0;
 			realloc_strcat(&buffer, *result);
 			name = buffer;
 			(*result)[0] = 0;
diff --git a/tar/test/test_option_s.c b/tar/test/test_option_s.c
index 1a36280c1..125e971d3 100644
--- a/tar/test/test_option_s.c
+++ b/tar/test/test_option_s.c
@@ -70,7 +70,7 @@ DEFINE_TEST(test_option_s)
 	assertFileContents("bar", 3, "test4/in/d1/baz");
 
 	/*
-	 * Test 4b: Multiple substitutions behavior with option b).
+	 * Test 4b: Multiple substitutions behavior with option b.
 	 */
 	assertMakeDir("test4b", 0755);
 	systemf("%s -cf test4b.tar in/d1/foo in/d1/bar",
@@ -80,6 +80,18 @@ DEFINE_TEST(test_option_s)
 	assertFileContents("foo", 3, "test4b/in/d1/faz");
 	assertFileContents("bar", 3, "test4b/in/d1/baz");
 
+	/*
+	 * Test 4bb: Multiple substitutions with option b
+	 * (libarchive/libarchive#2414 GitHub issue regression test).
+	 */
+	assertMakeDir("test4bb", 0755);
+	systemf("%s -cf test4bb.tar in/d1/foo in/d1/bar",
+	    testprog);
+	systemf("%s -xf test4bb.tar -s /oo/ar/ -s }ar}az}b -s :az:end:b -C test4bb",
+	    testprog);
+	assertFileContents("foo", 3, "test4bb/in/d1/fend");
+	assertFileContents("bar", 3, "test4bb/in/d1/bend");
+
 	/*
 	 * Test 5: Name-switching substitutions when extracting archive.
 	 */