From: David Disseldorp Date: Tue, 31 Mar 2026 06:57:31 +0000 (+1100) Subject: initramfs_test: add fill_cpio() inject_ox parameter X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=8d14fe78cb5ac5b7ac85f5fbf0be9afb3a3dba0e;p=thirdparty%2Fkernel%2Flinux.git initramfs_test: add fill_cpio() inject_ox parameter fill_cpio() uses sprintf() to write out the in-memory cpio archive from an array of struct initramfs_test_cpio. This change allows callers to modify the cpio sprintf() format string so that future tests can intentionally corrupt the header with "0x" and "0X" prefixed fields. Signed-off-by: David Disseldorp Link: https://patch.msgid.link/20260331070519.5974-2-ddiss@suse.de Reviewed-by: Andy Shevchenko Reviewed-by: Petr Mladek Signed-off-by: Christian Brauner --- diff --git a/init/initramfs_test.c b/init/initramfs_test.c index 2ce38d9a8fd0f..6fe1c44a74a58 100644 --- a/init/initramfs_test.c +++ b/init/initramfs_test.c @@ -27,7 +27,18 @@ struct initramfs_test_cpio { char *data; }; -static size_t fill_cpio(struct initramfs_test_cpio *cs, size_t csz, char *out) +/* regular newc header format */ +#define CPIO_HDR_FMT "%s%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%s" +/* + * Bogus newc header with "0x" prefixes on the uid, gid, and namesize values. + * parse_header()/simple_str[n]toul() accept this, contrary to the initramfs + * specification. + */ +#define CPIO_HDR_OX_INJECT \ + "%s%08x%08x0x%06x0X%06x%08x%08x%08x%08x%08x%08x%08x0x%06x%08x%s" + +static size_t fill_cpio(struct initramfs_test_cpio *cs, size_t csz, + bool inject_ox, char *out) { int i; size_t off = 0; @@ -38,9 +49,8 @@ static size_t fill_cpio(struct initramfs_test_cpio *cs, size_t csz, char *out) 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", + thislen = sprintf(pos, + inject_ox ? CPIO_HDR_OX_INJECT : CPIO_HDR_FMT, 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, @@ -102,7 +112,7 @@ static void __init initramfs_test_extract(struct kunit *test) /* +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); + len = fill_cpio(c, ARRAY_SIZE(c), false, cpio_srcbuf); ktime_get_real_ts64(&ts_before); err = unpack_to_rootfs(cpio_srcbuf, len); @@ -177,7 +187,7 @@ static void __init initramfs_test_fname_overrun(struct kunit *test) /* 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); + len = fill_cpio(c, ARRAY_SIZE(c), false, cpio_srcbuf); /* overwrite trailing fname terminator and padding */ suffix_off = len - 1; while (cpio_srcbuf[suffix_off] == '\0') { @@ -219,7 +229,7 @@ static void __init initramfs_test_data(struct kunit *test) cpio_srcbuf = kmalloc(CPIO_HDRLEN + c[0].namesize + c[0].filesize + 6, GFP_KERNEL); - len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf); + len = fill_cpio(c, ARRAY_SIZE(c), false, cpio_srcbuf); err = unpack_to_rootfs(cpio_srcbuf, len); KUNIT_EXPECT_NULL(test, err); @@ -274,7 +284,7 @@ static void __init initramfs_test_csum(struct kunit *test) cpio_srcbuf = kmalloc(8192, GFP_KERNEL); - len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf); + len = fill_cpio(c, ARRAY_SIZE(c), false, cpio_srcbuf); err = unpack_to_rootfs(cpio_srcbuf, len); KUNIT_EXPECT_NULL(test, err); @@ -284,7 +294,7 @@ static void __init initramfs_test_csum(struct kunit *test) /* mess up the csum and confirm that unpack fails */ c[0].csum--; - len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf); + len = fill_cpio(c, ARRAY_SIZE(c), false, cpio_srcbuf); err = unpack_to_rootfs(cpio_srcbuf, len); KUNIT_EXPECT_NOT_NULL(test, err); @@ -330,7 +340,7 @@ static void __init initramfs_test_hardlink(struct kunit *test) cpio_srcbuf = kmalloc(8192, GFP_KERNEL); - len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf); + len = fill_cpio(c, ARRAY_SIZE(c), false, cpio_srcbuf); err = unpack_to_rootfs(cpio_srcbuf, len); KUNIT_EXPECT_NULL(test, err); @@ -371,7 +381,7 @@ static void __init initramfs_test_many(struct kunit *test) }; c.namesize = 1 + sprintf(thispath, "initramfs_test_many-%d", i); - p += fill_cpio(&c, 1, p); + p += fill_cpio(&c, 1, false, p); } len = p - cpio_srcbuf; @@ -425,7 +435,7 @@ static void __init initramfs_test_fname_pad(struct kunit *test) } }; memcpy(tbufs->padded_fname, "padded_fname", sizeof("padded_fname")); - len = fill_cpio(c, ARRAY_SIZE(c), tbufs->cpio_srcbuf); + len = fill_cpio(c, ARRAY_SIZE(c), false, tbufs->cpio_srcbuf); err = unpack_to_rootfs(tbufs->cpio_srcbuf, len); KUNIT_EXPECT_NULL(test, err); @@ -481,7 +491,7 @@ static void __init initramfs_test_fname_path_max(struct kunit *test) memcpy(tbufs->fname_oversize, "fname_oversize", sizeof("fname_oversize") - 1); memcpy(tbufs->fname_ok, "fname_ok", sizeof("fname_ok") - 1); - len = fill_cpio(c, ARRAY_SIZE(c), tbufs->cpio_src); + len = fill_cpio(c, ARRAY_SIZE(c), false, tbufs->cpio_src); /* unpack skips over fname_oversize instead of returning an error */ err = unpack_to_rootfs(tbufs->cpio_src, len);