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");