From: Martin Matuška <martin@matuska.de>
Date: Mon, 1 Jun 2026 07:54:26 +0000 (+0200)
Subject: Merge pull request #3095 from stoeckmann/afio_header
X-Git-Tag: v3.8.8~74
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0332996f6fd8beaeeaba429f904c90ea1dce2e11;p=thirdparty%2Flibarchive.git

Merge pull request #3095 from stoeckmann/afio_header

cpio: Improve afio header detection
(cherry picked from commit 36d69b3ec81affb13f8b1deadd7dcc8bfeb81459)
---

diff --git a/Makefile.am b/Makefile.am
index 9d9a637a9..feee8b399 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -897,6 +897,8 @@ libarchive_test_EXTRA_DIST=\
 	libarchive/test/test_read_format_cab_filename_cp932.cab.uu \
 	libarchive/test/test_read_format_cab_lzx_oob.cab.uu \
 	libarchive/test/test_read_format_cab_skip_malformed.cab.uu \
+	libarchive/test/test_read_format_cpio_afio_header.part1.cpio.uu \
+	libarchive/test/test_read_format_cpio_afio_header.part2.cpio.uu \
 	libarchive/test/test_read_format_cpio_bin_be.cpio.uu \
 	libarchive/test/test_read_format_cpio_bin_le.cpio.uu \
 	libarchive/test/test_read_format_cpio_filename_cp866.cpio.uu \
diff --git a/libarchive/archive_read_support_format_cpio.c b/libarchive/archive_read_support_format_cpio.c
index 4fd5f1383..e108843b3 100644
--- a/libarchive/archive_read_support_format_cpio.c
+++ b/libarchive/archive_read_support_format_cpio.c
@@ -713,13 +713,24 @@ find_odc_header(struct archive_read *a)
 {
 	const void *h;
 	const char *p, *q;
-	size_t skip, skipped = 0;
+	int64_t skip;
+	uintmax_t skipped = 0;
 	ssize_t bytes;
 
 	for (;;) {
-		h = __archive_read_ahead(a, odc_header_size, &bytes);
-		if (h == NULL)
-			return (ARCHIVE_FATAL);
+		size_t header_size;
+
+		header_size = afiol_header_size;
+		h = __archive_read_ahead(a, afiol_header_size, &bytes);
+		if (h == NULL) {
+			if (bytes >= odc_header_size) {
+				header_size = odc_header_size;
+				h = __archive_read_ahead(a, odc_header_size,
+				    &bytes);
+			}
+			if (h == NULL)
+				return (ARCHIVE_FATAL);
+		}
 		p = h;
 		q = p + bytes;
 
@@ -735,7 +746,7 @@ find_odc_header(struct archive_read *a)
 		 * Scan ahead until we find something that looks
 		 * like an odc header.
 		 */
-		while (p + odc_header_size <= q) {
+		while (p + header_size <= q) {
 			switch (p[5]) {
 			case '7':
 				if ((memcmp("070707", p, 6) == 0
@@ -751,9 +762,9 @@ find_odc_header(struct archive_read *a)
 					if (skipped > 0) {
 						archive_set_error(&a->archive,
 						    0,
-						    "Skipped %d bytes before "
+						    "Skipped %ju bytes before "
 						    "finding valid header",
-						    (int)skipped);
+						    skipped);
 						return (ARCHIVE_WARN);
 					}
 					return (ARCHIVE_OK);
diff --git a/libarchive/test/test_read_format_cpio_afio.c b/libarchive/test/test_read_format_cpio_afio.c
index be386e1f4..a1fb683e3 100644
--- a/libarchive/test/test_read_format_cpio_afio.c
+++ b/libarchive/test/test_read_format_cpio_afio.c
@@ -125,3 +125,27 @@ DEFINE_TEST(test_read_format_cpio_afio_broken)
 	assertEqualInt(archive_format(a), ARCHIVE_FORMAT_CPIO_AFIO_LARGE);
 	archive_read_free(a);
 }
+
+DEFINE_TEST(test_read_format_cpio_afio_header)
+{
+  const char *reffiles[] =
+  {
+    "test_read_format_cpio_afio_header.part1.cpio",
+    "test_read_format_cpio_afio_header.part2.cpio",
+    NULL
+  };
+  struct archive_entry *ae;
+  struct archive *a;
+
+  extract_reference_files(reffiles);
+  assert((a = archive_read_new()) != NULL);
+  assertA(0 == archive_read_support_format_cpio(a));
+  assertA(0 == archive_read_open_filenames(a, reffiles, 10240));
+
+  /* File "a" */
+  assertEqualIntA(a, ARCHIVE_OK, archive_read_next_header(a, &ae));
+  assertEqualString("a", archive_entry_pathname(ae));
+
+  assertEqualIntA(a, ARCHIVE_OK, archive_read_close(a));
+  assertEqualInt(ARCHIVE_OK, archive_read_free(a));
+}
diff --git a/libarchive/test/test_read_format_cpio_afio_header.part1.cpio.uu b/libarchive/test/test_read_format_cpio_afio_header.part1.cpio.uu
new file mode 100644
index 000000000..0d06cb299
--- /dev/null
+++ b/libarchive/test/test_read_format_cpio_afio_header.part1.cpio.uu
@@ -0,0 +1,5 @@
+begin 644 test_read_format_cpio_afio_header.part1.cpio
+M,#<P-S(W,#`P,#`P,#`P,#`P,#`P,#`P,#`P,#`P;3`P,#`P,#`P,#`P,#`P
+?,#`P,#`P,#`P,#`P,#`P,#`P,#`P,#`P,#`P,#`P,```
+`
+end
diff --git a/libarchive/test/test_read_format_cpio_afio_header.part2.cpio.uu b/libarchive/test/test_read_format_cpio_afio_header.part2.cpio.uu
new file mode 100644
index 000000000..0a3d59597
--- /dev/null
+++ b/libarchive/test/test_read_format_cpio_afio_header.part2.cpio.uu
@@ -0,0 +1,4 @@
+begin 644 test_read_format_cpio_afio_header.part2.cpio
+I,#`P,#`P,#`P;C`P,#$P,#`P,#`P,',P,#`P,#`P,#`P,#`P,#`P.F$`
+`
+end