From 707cc7280f452a162c52bc240eae62568b9753c2 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 6 Nov 2015 16:30:29 -0800 Subject: [PATCH] test_printf: test printf family at runtime This adds a simple module for testing the kernel's printf facilities. Previously, some %p extensions have caused a wrong return value in case the entire output didn't fit and/or been unusable in kasprintf(). This should help catch such issues. Also, it should help ensure that changes to the formatting algorithms don't break anything. I'm not sure if we have a struct dentry or struct file lying around at boot time or if we can fake one, but most %p extensions should be testable, as should the ordinary number and string formatting. The nature of vararg functions means we can't use a more conventional table-driven approach. For now, this is mostly a skeleton; contributions are very welcome. Some tests are/will be slightly annoying to write, since the expected output depends on stuff like CONFIG_*, sizeof(long), runtime values etc. Signed-off-by: Rasmus Villemoes Reviewed-by: Kees Cook Cc: Andy Shevchenko Cc: Martin Kletzander Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.debug | 3 + lib/Makefile | 1 + lib/test_printf.c | 362 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 366 insertions(+) create mode 100644 lib/test_printf.c diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 1d1521c26302..16bf3bc25e3e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1686,6 +1686,9 @@ config TEST_STRING_HELPERS config TEST_KSTRTOX tristate "Test kstrto*() family of functions at runtime" +config TEST_PRINTF + tristate "Test printf() family of functions at runtime" + config TEST_RHASHTABLE tristate "Perform selftest on resizable hash table" default n diff --git a/lib/Makefile b/lib/Makefile index 8de3b012eac7..7f1de26613d2 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -42,6 +42,7 @@ obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o +obj-$(CONFIG_TEST_PRINTF) += test_printf.o ifeq ($(CONFIG_DEBUG_KOBJECT),y) CFLAGS_kobject.o += -DDEBUG diff --git a/lib/test_printf.c b/lib/test_printf.c new file mode 100644 index 000000000000..c5a666af9ba5 --- /dev/null +++ b/lib/test_printf.c @@ -0,0 +1,362 @@ +/* + * Test cases for printf facility. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#define BUF_SIZE 256 +#define FILL_CHAR '$' + +#define PTR1 ((void*)0x01234567) +#define PTR2 ((void*)(long)(int)0xfedcba98) + +#if BITS_PER_LONG == 64 +#define PTR1_ZEROES "000000000" +#define PTR1_SPACES " " +#define PTR1_STR "1234567" +#define PTR2_STR "fffffffffedcba98" +#define PTR_WIDTH 16 +#else +#define PTR1_ZEROES "0" +#define PTR1_SPACES " " +#define PTR1_STR "1234567" +#define PTR2_STR "fedcba98" +#define PTR_WIDTH 8 +#endif +#define PTR_WIDTH_STR stringify(PTR_WIDTH) + +static unsigned total_tests __initdata; +static unsigned failed_tests __initdata; +static char *test_buffer __initdata; + +static int __printf(4, 0) __init +do_test(int bufsize, const char *expect, int elen, + const char *fmt, va_list ap) +{ + va_list aq; + int ret, written; + + total_tests++; + + memset(test_buffer, FILL_CHAR, BUF_SIZE); + va_copy(aq, ap); + ret = vsnprintf(test_buffer, bufsize, fmt, aq); + va_end(aq); + + if (ret != elen) { + pr_warn("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d\n", + bufsize, fmt, ret, elen); + return 1; + } + + if (!bufsize) { + if (memchr_inv(test_buffer, FILL_CHAR, BUF_SIZE)) { + pr_warn("vsnprintf(buf, 0, \"%s\", ...) wrote to buffer\n", + fmt); + return 1; + } + return 0; + } + + written = min(bufsize-1, elen); + if (test_buffer[written]) { + pr_warn("vsnprintf(buf, %d, \"%s\", ...) did not nul-terminate buffer\n", + bufsize, fmt); + return 1; + } + + if (memcmp(test_buffer, expect, written)) { + pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'\n", + bufsize, fmt, test_buffer, written, expect); + return 1; + } + return 0; +} + +static void __printf(3, 4) __init +__test(const char *expect, int elen, const char *fmt, ...) +{ + va_list ap; + int rand; + char *p; + + BUG_ON(elen >= BUF_SIZE); + + va_start(ap, fmt); + + /* + * Every fmt+args is subjected to four tests: Three where we + * tell vsnprintf varying buffer sizes (plenty, not quite + * enough and 0), and then we also test that kvasprintf would + * be able to print it as expected. + */ + failed_tests += do_test(BUF_SIZE, expect, elen, fmt, ap); + rand = 1 + prandom_u32_max(elen+1); + /* Since elen < BUF_SIZE, we have 1 <= rand <= BUF_SIZE. */ + failed_tests += do_test(rand, expect, elen, fmt, ap); + failed_tests += do_test(0, expect, elen, fmt, ap); + + p = kvasprintf(GFP_KERNEL, fmt, ap); + if (p) { + if (memcmp(p, expect, elen+1)) { + pr_warn("kvasprintf(..., \"%s\", ...) returned '%s', expected '%s'\n", + fmt, p, expect); + failed_tests++; + } + kfree(p); + } + va_end(ap); +} + +#define test(expect, fmt, ...) \ + __test(expect, strlen(expect), fmt, ##__VA_ARGS__) + +static void __init +test_basic(void) +{ + /* Work around annoying "warning: zero-length gnu_printf format string". */ + char nul = '\0'; + + test("", &nul); + test("100%", "100%%"); + test("xxx%yyy", "xxx%cyyy", '%'); + __test("xxx\0yyy", 7, "xxx%cyyy", '\0'); +} + +static void __init +test_number(void) +{ + test("0x1234abcd ", "%#-12x", 0x1234abcd); + test(" 0x1234abcd", "%#12x", 0x1234abcd); + test("0|001| 12|+123| 1234|-123|-1234", "%d|%03d|%3d|%+d|% d|%+d|% d", 0, 1, 12, 123, 1234, -123, -1234); +} + +static void __init +test_string(void) +{ + test("", "%s%.0s", "", "123"); + test("ABCD|abc|123", "%s|%.3s|%.*s", "ABCD", "abcdef", 3, "123456"); + test("1 | 2|3 | 4|5 ", "%-3s|%3s|%-*s|%*s|%*s", "1", "2", 3, "3", 3, "4", -3, "5"); + /* + * POSIX and C99 say that a missing precision should be + * treated as a precision of 0. However, the kernel's printf + * implementation treats this case as if the . wasn't + * present. Let's add a test case documenting the current + * behaviour; should anyone ever feel the need to follow the + * standards more closely, this can be revisited. + */ + test("a||", "%.s|%.0s|%.*s", "a", "b", 0, "c"); + test("a | | ", "%-3.s|%-3.0s|%-3.*s", "a", "b", 0, "c"); +} + +static void __init +plain(void) +{ + test(PTR1_ZEROES PTR1_STR " " PTR2_STR, "%p %p", PTR1, PTR2); + /* + * The field width is overloaded for some %p extensions to + * pass another piece of information. For plain pointers, the + * behaviour is slightly odd: One cannot pass either the 0 + * flag nor a precision to %p without gcc complaining, and if + * one explicitly gives a field width, the number is no longer + * zero-padded. + */ + test("|" PTR1_STR PTR1_SPACES " | " PTR1_SPACES PTR1_STR "|", + "|%-*p|%*p|", PTR_WIDTH+2, PTR1, PTR_WIDTH+2, PTR1); + test("|" PTR2_STR " | " PTR2_STR "|", + "|%-*p|%*p|", PTR_WIDTH+2, PTR2, PTR_WIDTH+2, PTR2); + + /* + * Unrecognized %p extensions are treated as plain %p, but the + * alphanumeric suffix is ignored (that is, does not occur in + * the output.) + */ + test("|"PTR1_ZEROES PTR1_STR"|", "|%p0y|", PTR1); + test("|"PTR2_STR"|", "|%p0y|", PTR2); +} + +static void __init +symbol_ptr(void) +{ +} + +static void __init +kernel_ptr(void) +{ +} + +static void __init +struct_resource(void) +{ +} + +static void __init +addr(void) +{ +} + +static void __init +escaped_str(void) +{ +} + +static void __init +hex_string(void) +{ + const char buf[3] = {0xc0, 0xff, 0xee}; + + test("c0 ff ee|c0:ff:ee|c0-ff-ee|c0ffee", + "%3ph|%3phC|%3phD|%3phN", buf, buf, buf, buf); + test("c0 ff ee|c0:ff:ee|c0-ff-ee|c0ffee", + "%*ph|%*phC|%*phD|%*phN", 3, buf, 3, buf, 3, buf, 3, buf); +} + +static void __init +mac(void) +{ + const u8 addr[6] = {0x2d, 0x48, 0xd6, 0xfc, 0x7a, 0x05}; + + test("2d:48:d6:fc:7a:05", "%pM", addr); + test("05:7a:fc:d6:48:2d", "%pMR", addr); + test("2d-48-d6-fc-7a-05", "%pMF", addr); + test("2d48d6fc7a05", "%pm", addr); + test("057afcd6482d", "%pmR", addr); +} + +static void __init +ip4(void) +{ + struct sockaddr_in sa; + + sa.sin_family = AF_INET; + sa.sin_port = cpu_to_be16(12345); + sa.sin_addr.s_addr = cpu_to_be32(0x7f000001); + + test("127.000.000.001|127.0.0.1", "%pi4|%pI4", &sa.sin_addr, &sa.sin_addr); + test("127.000.000.001|127.0.0.1", "%piS|%pIS", &sa, &sa); + sa.sin_addr.s_addr = cpu_to_be32(0x01020304); + test("001.002.003.004:12345|1.2.3.4:12345", "%piSp|%pISp", &sa, &sa); +} + +static void __init +ip6(void) +{ +} + +static void __init +ip(void) +{ + ip4(); + ip6(); +} + +static void __init +uuid(void) +{ + const char uuid[16] = {0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, + 0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf}; + + test("00010203-0405-0607-0809-0a0b0c0d0e0f", "%pUb", uuid); + test("00010203-0405-0607-0809-0A0B0C0D0E0F", "%pUB", uuid); + test("03020100-0504-0706-0809-0a0b0c0d0e0f", "%pUl", uuid); + test("03020100-0504-0706-0809-0A0B0C0D0E0F", "%pUL", uuid); +} + +static void __init +dentry(void) +{ +} + +static void __init +struct_va_format(void) +{ +} + +static void __init +struct_clk(void) +{ +} + +static void __init +bitmap(void) +{ + DECLARE_BITMAP(bits, 20); + const int primes[] = {2,3,5,7,11,13,17,19}; + int i; + + bitmap_zero(bits, 20); + test("00000|00000", "%20pb|%*pb", bits, 20, bits); + test("|", "%20pbl|%*pbl", bits, 20, bits); + + for (i = 0; i < ARRAY_SIZE(primes); ++i) + set_bit(primes[i], bits); + test("a28ac|a28ac", "%20pb|%*pb", bits, 20, bits); + test("2-3,5,7,11,13,17,19|2-3,5,7,11,13,17,19", "%20pbl|%*pbl", bits, 20, bits); + + bitmap_fill(bits, 20); + test("fffff|fffff", "%20pb|%*pb", bits, 20, bits); + test("0-19|0-19", "%20pbl|%*pbl", bits, 20, bits); +} + +static void __init +netdev_features(void) +{ +} + +static void __init +test_pointer(void) +{ + plain(); + symbol_ptr(); + kernel_ptr(); + struct_resource(); + addr(); + escaped_str(); + hex_string(); + mac(); + ip(); + uuid(); + dentry(); + struct_va_format(); + struct_clk(); + bitmap(); + netdev_features(); +} + +static int __init +test_printf_init(void) +{ + test_buffer = kmalloc(BUF_SIZE, GFP_KERNEL); + if (!test_buffer) + return -ENOMEM; + + test_basic(); + test_number(); + test_string(); + test_pointer(); + + kfree(test_buffer); + + if (failed_tests == 0) + pr_info("all %u tests passed\n", total_tests); + else + pr_warn("failed %u out of %u tests\n", failed_tests, total_tests); + + return failed_tests ? -EINVAL : 0; +} + +module_init(test_printf_init); + +MODULE_AUTHOR("Rasmus Villemoes "); +MODULE_LICENSE("GPL");