From: David Disseldorp <ddiss@suse.de>
To: linux-fsdevel@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
David Disseldorp <ddiss@suse.de>
Subject: [PATCH v4 2/8] initramfs_test: kunit tests for initramfs unpacking
Date: Tue, 4 Mar 2025 16:57:45 +1100 [thread overview]
Message-ID: <20250304061020.9815-3-ddiss@suse.de> (raw)
In-Reply-To: <20250304061020.9815-1-ddiss@suse.de>
Provide some basic initramfs unpack sanity tests covering:
- simple file / dir extraction
- filename field overrun, as reported and fixed separately via
https://lore.kernel.org/r/20241030035509.20194-2-ddiss@suse.de
- "070702" cpio data checksums
- hardlinks
These tests introduce new modpost warnings for initramfs_test_cases
section=.data -> section=.init.text run_case() hooks. The
kunit_case/_suite struct cannot be marked as __initdata as this
will be used in debugfs to retrieve results after a test has run.
Signed-off-by: David Disseldorp <ddiss@suse.de>
---
init/.kunitconfig | 3 +
init/Kconfig | 7 +
init/Makefile | 1 +
init/initramfs_test.c | 407 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 418 insertions(+)
create mode 100644 init/.kunitconfig
create mode 100644 init/initramfs_test.c
diff --git a/init/.kunitconfig b/init/.kunitconfig
new file mode 100644
index 0000000000000..acb906b1a5f98
--- /dev/null
+++ b/init/.kunitconfig
@@ -0,0 +1,3 @@
+CONFIG_KUNIT=y
+CONFIG_BLK_DEV_INITRD=y
+CONFIG_INITRAMFS_TEST=y
diff --git a/init/Kconfig b/init/Kconfig
index d0d021b3fa3b3..ded64f6c949ed 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1454,6 +1454,13 @@ config INITRAMFS_PRESERVE_MTIME
If unsure, say Y.
+config INITRAMFS_TEST
+ bool "Test initramfs cpio archive extraction" if !KUNIT_ALL_TESTS
+ depends on BLK_DEV_INITRD && KUNIT=y
+ default KUNIT_ALL_TESTS
+ help
+ Build KUnit tests for initramfs. See Documentation/dev-tools/kunit
+
choice
prompt "Compiler optimization level"
default CC_OPTIMIZE_FOR_PERFORMANCE
diff --git a/init/Makefile b/init/Makefile
index 10b652d33e872..d6f75d8907e09 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -12,6 +12,7 @@ else
obj-$(CONFIG_BLK_DEV_INITRD) += initramfs.o
endif
obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
+obj-$(CONFIG_INITRAMFS_TEST) += initramfs_test.o
obj-y += init_task.o
diff --git a/init/initramfs_test.c b/init/initramfs_test.c
new file mode 100644
index 0000000000000..6231fe0125831
--- /dev/null
+++ b/init/initramfs_test.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/init_syscalls.h>
+#include <linux/stringify.h>
+#include <linux/timekeeping.h>
+#include "initramfs_internal.h"
+
+struct initramfs_test_cpio {
+ char *magic;
+ unsigned int ino;
+ unsigned int mode;
+ unsigned int uid;
+ unsigned int gid;
+ unsigned int nlink;
+ unsigned int mtime;
+ unsigned int filesize;
+ unsigned int devmajor;
+ unsigned int devminor;
+ unsigned int rdevmajor;
+ unsigned int rdevminor;
+ unsigned int namesize;
+ unsigned int csum;
+ char *fname;
+ char *data;
+};
+
+static size_t fill_cpio(struct initramfs_test_cpio *cs, size_t csz, char *out)
+{
+ int i;
+ size_t off = 0;
+
+ for (i = 0; i < csz; i++) {
+ char *pos = &out[off];
+ struct initramfs_test_cpio *c = &cs[i];
+ size_t thislen;
+
+ /* +1 to account for nulterm */
+ thislen = sprintf(pos, "%s"
+ "%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x"
+ "%s",
+ c->magic, c->ino, c->mode, c->uid, c->gid, c->nlink,
+ c->mtime, c->filesize, c->devmajor, c->devminor,
+ c->rdevmajor, c->rdevminor, c->namesize, c->csum,
+ c->fname) + 1;
+ pr_debug("packing (%zu): %.*s\n", thislen, (int)thislen, pos);
+ off += thislen;
+ while (off & 3)
+ out[off++] = '\0';
+
+ memcpy(&out[off], c->data, c->filesize);
+ off += c->filesize;
+ while (off & 3)
+ out[off++] = '\0';
+ }
+
+ return off;
+}
+
+static void __init initramfs_test_extract(struct kunit *test)
+{
+ char *err, *cpio_srcbuf;
+ size_t len;
+ struct timespec64 ts_before, ts_after;
+ struct kstat st = {};
+ struct initramfs_test_cpio c[] = { {
+ .magic = "070701",
+ .ino = 1,
+ .mode = S_IFREG | 0777,
+ .uid = 12,
+ .gid = 34,
+ .nlink = 1,
+ .mtime = 56,
+ .filesize = 0,
+ .devmajor = 0,
+ .devminor = 1,
+ .rdevmajor = 0,
+ .rdevminor = 0,
+ .namesize = sizeof("initramfs_test_extract"),
+ .csum = 0,
+ .fname = "initramfs_test_extract",
+ }, {
+ .magic = "070701",
+ .ino = 2,
+ .mode = S_IFDIR | 0777,
+ .nlink = 1,
+ .mtime = 57,
+ .devminor = 1,
+ .namesize = sizeof("initramfs_test_extract_dir"),
+ .fname = "initramfs_test_extract_dir",
+ }, {
+ .magic = "070701",
+ .namesize = sizeof("TRAILER!!!"),
+ .fname = "TRAILER!!!",
+ } };
+
+ /* +3 to cater for any 4-byte end-alignment */
+ cpio_srcbuf = kzalloc(ARRAY_SIZE(c) * (CPIO_HDRLEN + PATH_MAX + 3),
+ GFP_KERNEL);
+ len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);
+
+ ktime_get_real_ts64(&ts_before);
+ err = unpack_to_rootfs(cpio_srcbuf, len);
+ ktime_get_real_ts64(&ts_after);
+ if (err) {
+ KUNIT_FAIL(test, "unpack failed %s", err);
+ goto out;
+ }
+
+ KUNIT_EXPECT_EQ(test, init_stat(c[0].fname, &st, 0), 0);
+ KUNIT_EXPECT_TRUE(test, S_ISREG(st.mode));
+ KUNIT_EXPECT_TRUE(test, uid_eq(st.uid, KUIDT_INIT(c[0].uid)));
+ KUNIT_EXPECT_TRUE(test, gid_eq(st.gid, KGIDT_INIT(c[0].gid)));
+ KUNIT_EXPECT_EQ(test, st.nlink, 1);
+ if (IS_ENABLED(CONFIG_INITRAMFS_PRESERVE_MTIME)) {
+ KUNIT_EXPECT_EQ(test, st.mtime.tv_sec, c[0].mtime);
+ } else {
+ KUNIT_EXPECT_GE(test, st.mtime.tv_sec, ts_before.tv_sec);
+ KUNIT_EXPECT_LE(test, st.mtime.tv_sec, ts_after.tv_sec);
+ }
+ KUNIT_EXPECT_EQ(test, st.blocks, c[0].filesize);
+
+ KUNIT_EXPECT_EQ(test, init_stat(c[1].fname, &st, 0), 0);
+ KUNIT_EXPECT_TRUE(test, S_ISDIR(st.mode));
+ if (IS_ENABLED(CONFIG_INITRAMFS_PRESERVE_MTIME)) {
+ KUNIT_EXPECT_EQ(test, st.mtime.tv_sec, c[1].mtime);
+ } else {
+ KUNIT_EXPECT_GE(test, st.mtime.tv_sec, ts_before.tv_sec);
+ KUNIT_EXPECT_LE(test, st.mtime.tv_sec, ts_after.tv_sec);
+ }
+
+ KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
+ KUNIT_EXPECT_EQ(test, init_rmdir(c[1].fname), 0);
+out:
+ kfree(cpio_srcbuf);
+}
+
+/*
+ * Don't terminate filename. Previously, the cpio filename field was passed
+ * directly to filp_open(collected, O_CREAT|..) without nulterm checks. See
+ * https://lore.kernel.org/linux-fsdevel/20241030035509.20194-2-ddiss@suse.de
+ */
+static void __init initramfs_test_fname_overrun(struct kunit *test)
+{
+ char *err, *cpio_srcbuf;
+ size_t len, suffix_off;
+ struct initramfs_test_cpio c[] = { {
+ .magic = "070701",
+ .ino = 1,
+ .mode = S_IFREG | 0777,
+ .uid = 0,
+ .gid = 0,
+ .nlink = 1,
+ .mtime = 1,
+ .filesize = 0,
+ .devmajor = 0,
+ .devminor = 1,
+ .rdevmajor = 0,
+ .rdevminor = 0,
+ .namesize = sizeof("initramfs_test_fname_overrun"),
+ .csum = 0,
+ .fname = "initramfs_test_fname_overrun",
+ } };
+
+ /*
+ * poison cpio source buffer, so we can detect overrun. source
+ * buffer is used by read_into() when hdr or fname
+ * are already available (e.g. no compression).
+ */
+ cpio_srcbuf = kmalloc(CPIO_HDRLEN + PATH_MAX + 3, GFP_KERNEL);
+ memset(cpio_srcbuf, 'B', CPIO_HDRLEN + PATH_MAX + 3);
+ /* limit overrun to avoid crashes / filp_open() ENAMETOOLONG */
+ cpio_srcbuf[CPIO_HDRLEN + strlen(c[0].fname) + 20] = '\0';
+
+ len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);
+ /* overwrite trailing fname terminator and padding */
+ suffix_off = len - 1;
+ while (cpio_srcbuf[suffix_off] == '\0') {
+ cpio_srcbuf[suffix_off] = 'P';
+ suffix_off--;
+ }
+
+ err = unpack_to_rootfs(cpio_srcbuf, len);
+ KUNIT_EXPECT_NOT_NULL(test, err);
+
+ kfree(cpio_srcbuf);
+}
+
+static void __init initramfs_test_data(struct kunit *test)
+{
+ char *err, *cpio_srcbuf;
+ size_t len;
+ struct file *file;
+ struct initramfs_test_cpio c[] = { {
+ .magic = "070701",
+ .ino = 1,
+ .mode = S_IFREG | 0777,
+ .uid = 0,
+ .gid = 0,
+ .nlink = 1,
+ .mtime = 1,
+ .filesize = sizeof("ASDF") - 1,
+ .devmajor = 0,
+ .devminor = 1,
+ .rdevmajor = 0,
+ .rdevminor = 0,
+ .namesize = sizeof("initramfs_test_data"),
+ .csum = 0,
+ .fname = "initramfs_test_data",
+ .data = "ASDF",
+ } };
+
+ /* +6 for max name and data 4-byte padding */
+ cpio_srcbuf = kmalloc(CPIO_HDRLEN + c[0].namesize + c[0].filesize + 6,
+ GFP_KERNEL);
+
+ len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);
+
+ err = unpack_to_rootfs(cpio_srcbuf, len);
+ KUNIT_EXPECT_NULL(test, err);
+
+ file = filp_open(c[0].fname, O_RDONLY, 0);
+ if (!file) {
+ KUNIT_FAIL(test, "open failed");
+ goto out;
+ }
+
+ /* read back file contents into @cpio_srcbuf and confirm match */
+ len = kernel_read(file, cpio_srcbuf, c[0].filesize, NULL);
+ KUNIT_EXPECT_EQ(test, len, c[0].filesize);
+ KUNIT_EXPECT_MEMEQ(test, cpio_srcbuf, c[0].data, len);
+
+ fput(file);
+ KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
+out:
+ kfree(cpio_srcbuf);
+}
+
+static void __init initramfs_test_csum(struct kunit *test)
+{
+ char *err, *cpio_srcbuf;
+ size_t len;
+ struct initramfs_test_cpio c[] = { {
+ /* 070702 magic indicates a valid csum is present */
+ .magic = "070702",
+ .ino = 1,
+ .mode = S_IFREG | 0777,
+ .nlink = 1,
+ .filesize = sizeof("ASDF") - 1,
+ .devminor = 1,
+ .namesize = sizeof("initramfs_test_csum"),
+ .csum = 'A' + 'S' + 'D' + 'F',
+ .fname = "initramfs_test_csum",
+ .data = "ASDF",
+ }, {
+ /* mix csum entry above with no-csum entry below */
+ .magic = "070701",
+ .ino = 2,
+ .mode = S_IFREG | 0777,
+ .nlink = 1,
+ .filesize = sizeof("ASDF") - 1,
+ .devminor = 1,
+ .namesize = sizeof("initramfs_test_csum_not_here"),
+ /* csum ignored */
+ .csum = 5555,
+ .fname = "initramfs_test_csum_not_here",
+ .data = "ASDF",
+ } };
+
+ cpio_srcbuf = kmalloc(8192, GFP_KERNEL);
+
+ len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);
+
+ err = unpack_to_rootfs(cpio_srcbuf, len);
+ KUNIT_EXPECT_NULL(test, err);
+
+ KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
+ KUNIT_EXPECT_EQ(test, init_unlink(c[1].fname), 0);
+
+ /* mess up the csum and confirm that unpack fails */
+ c[0].csum--;
+ len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);
+
+ err = unpack_to_rootfs(cpio_srcbuf, len);
+ KUNIT_EXPECT_NOT_NULL(test, err);
+
+ /*
+ * file (with content) is still retained in case of bad-csum abort.
+ * Perhaps we should change this.
+ */
+ KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
+ KUNIT_EXPECT_EQ(test, init_unlink(c[1].fname), -ENOENT);
+ kfree(cpio_srcbuf);
+}
+
+/*
+ * hardlink hashtable may leak when the archive omits a trailer:
+ * https://lore.kernel.org/r/20241107002044.16477-10-ddiss@suse.de/
+ */
+static void __init initramfs_test_hardlink(struct kunit *test)
+{
+ char *err, *cpio_srcbuf;
+ size_t len;
+ struct kstat st0, st1;
+ struct initramfs_test_cpio c[] = { {
+ .magic = "070701",
+ .ino = 1,
+ .mode = S_IFREG | 0777,
+ .nlink = 2,
+ .devminor = 1,
+ .namesize = sizeof("initramfs_test_hardlink"),
+ .fname = "initramfs_test_hardlink",
+ }, {
+ /* hardlink data is present in last archive entry */
+ .magic = "070701",
+ .ino = 1,
+ .mode = S_IFREG | 0777,
+ .nlink = 2,
+ .filesize = sizeof("ASDF") - 1,
+ .devminor = 1,
+ .namesize = sizeof("initramfs_test_hardlink_link"),
+ .fname = "initramfs_test_hardlink_link",
+ .data = "ASDF",
+ } };
+
+ cpio_srcbuf = kmalloc(8192, GFP_KERNEL);
+
+ len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);
+
+ err = unpack_to_rootfs(cpio_srcbuf, len);
+ KUNIT_EXPECT_NULL(test, err);
+
+ KUNIT_EXPECT_EQ(test, init_stat(c[0].fname, &st0, 0), 0);
+ KUNIT_EXPECT_EQ(test, init_stat(c[1].fname, &st1, 0), 0);
+ KUNIT_EXPECT_EQ(test, st0.ino, st1.ino);
+ KUNIT_EXPECT_EQ(test, st0.nlink, 2);
+ KUNIT_EXPECT_EQ(test, st1.nlink, 2);
+
+ KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
+ KUNIT_EXPECT_EQ(test, init_unlink(c[1].fname), 0);
+
+ kfree(cpio_srcbuf);
+}
+
+#define INITRAMFS_TEST_MANY_LIMIT 1000
+#define INITRAMFS_TEST_MANY_PATH_MAX (sizeof("initramfs_test_many-") \
+ + sizeof(__stringify(INITRAMFS_TEST_MANY_LIMIT)))
+static void __init initramfs_test_many(struct kunit *test)
+{
+ char *err, *cpio_srcbuf, *p;
+ size_t len = INITRAMFS_TEST_MANY_LIMIT *
+ (CPIO_HDRLEN + INITRAMFS_TEST_MANY_PATH_MAX + 3);
+ char thispath[INITRAMFS_TEST_MANY_PATH_MAX];
+ int i;
+
+ p = cpio_srcbuf = kmalloc(len, GFP_KERNEL);
+
+ for (i = 0; i < INITRAMFS_TEST_MANY_LIMIT; i++) {
+ struct initramfs_test_cpio c = {
+ .magic = "070701",
+ .ino = i,
+ .mode = S_IFREG | 0777,
+ .nlink = 1,
+ .devminor = 1,
+ .fname = thispath,
+ };
+
+ c.namesize = 1 + sprintf(thispath, "initramfs_test_many-%d", i);
+ p += fill_cpio(&c, 1, p);
+ }
+
+ len = p - cpio_srcbuf;
+ err = unpack_to_rootfs(cpio_srcbuf, len);
+ KUNIT_EXPECT_NULL(test, err);
+
+ for (i = 0; i < INITRAMFS_TEST_MANY_LIMIT; i++) {
+ sprintf(thispath, "initramfs_test_many-%d", i);
+ KUNIT_EXPECT_EQ(test, init_unlink(thispath), 0);
+ }
+
+ kfree(cpio_srcbuf);
+}
+
+/*
+ * The kunit_case/_suite struct cannot be marked as __initdata as this will be
+ * used in debugfs to retrieve results after test has run.
+ */
+static struct kunit_case initramfs_test_cases[] = {
+ KUNIT_CASE(initramfs_test_extract),
+ KUNIT_CASE(initramfs_test_fname_overrun),
+ KUNIT_CASE(initramfs_test_data),
+ KUNIT_CASE(initramfs_test_csum),
+ KUNIT_CASE(initramfs_test_hardlink),
+ KUNIT_CASE(initramfs_test_many),
+ {},
+};
+
+static struct kunit_suite initramfs_test_suite = {
+ .name = "initramfs",
+ .test_cases = initramfs_test_cases,
+};
+kunit_test_init_section_suites(&initramfs_test_suite);
+
+MODULE_DESCRIPTION("Initramfs KUnit test suite");
+MODULE_LICENSE("GPL v2");
--
2.43.0
next prev parent reply other threads:[~2025-03-04 6:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-04 5:57 [PATCH v4 0/8] initramfs: kunit tests and cleanups David Disseldorp
2025-03-04 5:57 ` [PATCH v4 1/8] init: add initramfs_internal.h David Disseldorp
2025-03-04 5:57 ` David Disseldorp [this message]
2025-03-04 5:57 ` [PATCH v4 3/8] vsprintf: add simple_strntoul David Disseldorp
2025-03-04 5:57 ` [PATCH v4 4/8] initramfs: avoid memcpy for hex header fields David Disseldorp
2025-03-04 5:57 ` [PATCH v4 5/8] initramfs: allocate heap buffers together David Disseldorp
2025-03-04 5:57 ` [PATCH v4 6/8] initramfs: reuse name_len for dir mtime tracking David Disseldorp
2025-03-04 5:57 ` [PATCH v4 7/8] initramfs: fix hardlink hash leak without TRAILER David Disseldorp
2025-03-04 5:57 ` [PATCH v4 8/8] initramfs: avoid static buffer for error message David Disseldorp
2025-03-04 8:54 ` [PATCH v4 0/8] initramfs: kunit tests and cleanups Christian Brauner
2025-03-05 13:09 ` [PATCH] initramfs_test: flag kunit_case __refdata to suppress warning David Disseldorp
2025-03-06 7:13 ` Christian Brauner
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