The existing code attempted to handle numbers by doing a strto[u]l(),
ignoring the field width, and then bitshifting the field out of the
converted value. If the string contains a run of valid digits longer
than will fit in a long or long long, this would overflow and no amount
of bitshifting can recover the correct value.
This patch fixes vsscanf to obey number field widths when parsing
the number.
A new _parse_integer_limit() is added that takes a limit for the number
of characters to parse. The number field conversion in vsscanf is changed
to use this new function.
The cases of a base prefix or leading '-' that is >= the maximum field
width is handled such that the result of a sccanf is consistent with the
observed behaviour of userland sscanf.
Signed-off-by: Richard Fitzgerald <[email protected]>
---
lib/kstrtox.c | 13 +++++--
lib/kstrtox.h | 2 ++
lib/vsprintf.c | 93 ++++++++++++++++++++++++++++++--------------------
3 files changed, 68 insertions(+), 40 deletions(-)
diff --git a/lib/kstrtox.c b/lib/kstrtox.c
index a14ccf905055..0ac2ee8bd9d0 100644
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -39,20 +39,22 @@ const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
/*
* Convert non-negative integer string representation in explicitly given radix
- * to an integer.
+ * to an integer. A maximum of max_chars characters will be converted.
+ *
* Return number of characters consumed maybe or-ed with overflow bit.
* If overflow occurs, result integer (incorrect) is still returned.
*
* Don't you dare use this function.
*/
-unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
+unsigned int _parse_integer_limit(const char *s, unsigned int base,
+ unsigned long long *p, size_t max_chars)
{
unsigned long long res;
unsigned int rv;
res = 0;
rv = 0;
- while (1) {
+ for (; max_chars > 0; max_chars--) {
unsigned int c = *s;
unsigned int lc = c | 0x20; /* don't tolower() this line */
unsigned int val;
@@ -82,6 +84,11 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
return rv;
}
+unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
+{
+ return _parse_integer_limit(s, base, p, INT_MAX);
+}
+
static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
{
unsigned long long _res;
diff --git a/lib/kstrtox.h b/lib/kstrtox.h
index 3b4637bcd254..4c6536f85cac 100644
--- a/lib/kstrtox.h
+++ b/lib/kstrtox.h
@@ -4,6 +4,8 @@
#define KSTRTOX_OVERFLOW (1U << 31)
const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
+unsigned int _parse_integer_limit(const char *s, unsigned int base,
+ unsigned long long *res, size_t max_chars);
unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res);
#endif
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 14c9a6af1b23..21145da468e0 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -53,29 +53,47 @@
#include <linux/string_helpers.h>
#include "kstrtox.h"
-/**
- * simple_strtoull - convert a string to an unsigned long long
- * @cp: The start of the string
- * @endp: A pointer to the end of the parsed string will be placed here
- * @base: The number base to use
- *
- * This function has caveats. Please use kstrtoull instead.
- */
-unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
+static unsigned long long simple_strntoull(const char *startp, size_t max_chars,
+ char **endp, unsigned int base)
{
- unsigned long long result;
+ const char *cp;
+ unsigned long long result = 0ULL;
unsigned int rv;
- cp = _parse_integer_fixup_radix(cp, &base);
- rv = _parse_integer(cp, base, &result);
+ if (max_chars == 0) {
+ cp = startp;
+ goto out;
+ }
+
+ cp = _parse_integer_fixup_radix(startp, &base);
+ if ((cp - startp) >= max_chars) {
+ cp = startp + max_chars;
+ goto out;
+ }
+
+ max_chars -= (cp - startp);
+ rv = _parse_integer_limit(cp, base, &result, max_chars);
/* FIXME */
cp += (rv & ~KSTRTOX_OVERFLOW);
-
+out:
if (endp)
*endp = (char *)cp;
return result;
}
+
+/**
+ * simple_strtoull - convert a string to an unsigned long long
+ * @cp: The start of the string
+ * @endp: A pointer to the end of the parsed string will be placed here
+ * @base: The number base to use
+ *
+ * This function has caveats. Please use kstrtoull instead.
+ */
+unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
+{
+ return simple_strntoull(cp, UINT_MAX, endp, base);
+}
EXPORT_SYMBOL(simple_strtoull);
/**
@@ -88,7 +106,7 @@ EXPORT_SYMBOL(simple_strtoull);
*/
unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
{
- return simple_strtoull(cp, endp, base);
+ return simple_strntoull(cp, UINT_MAX, endp, base);
}
EXPORT_SYMBOL(simple_strtoul);
@@ -109,6 +127,19 @@ long simple_strtol(const char *cp, char **endp, unsigned int base)
}
EXPORT_SYMBOL(simple_strtol);
+static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
+ unsigned int base)
+{
+ /*
+ * simple_strntoull safely handles receiving max_chars==0 in the
+ * case we start with max_chars==1 and find a '-' prefix.
+ */
+ if (*cp == '-' && max_chars > 0)
+ return -simple_strntoull(cp + 1, max_chars - 1, endp, base);
+
+ return simple_strntoull(cp, max_chars, endp, base);
+}
+
/**
* simple_strtoll - convert a string to a signed long long
* @cp: The start of the string
@@ -119,10 +150,7 @@ EXPORT_SYMBOL(simple_strtol);
*/
long long simple_strtoll(const char *cp, char **endp, unsigned int base)
{
- if (*cp == '-')
- return -simple_strtoull(cp + 1, endp, base);
-
- return simple_strtoull(cp, endp, base);
+ return simple_strntoll(cp, UINT_MAX, endp, base);
}
EXPORT_SYMBOL(simple_strtoll);
@@ -3433,8 +3461,11 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
str = skip_spaces(str);
digit = *str;
- if (is_sign && digit == '-')
+ if (is_sign && digit == '-') {
+ if (field_width == 1)
+ break;
digit = *(str + 1);
+ }
if (!digit
|| (base == 16 && !isxdigit(digit))
@@ -3444,25 +3475,13 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
break;
if (is_sign)
- val.s = qualifier != 'L' ?
- simple_strtol(str, &next, base) :
- simple_strtoll(str, &next, base);
+ val.s = simple_strntoll(str,
+ field_width > 0 ? field_width : UINT_MAX,
+ &next, base);
else
- val.u = qualifier != 'L' ?
- simple_strtoul(str, &next, base) :
- simple_strtoull(str, &next, base);
-
- if (field_width > 0 && next - str > field_width) {
- if (base == 0)
- _parse_integer_fixup_radix(str, &base);
- while (next - str > field_width) {
- if (is_sign)
- val.s = div_s64(val.s, base);
- else
- val.u = div_u64(val.u, base);
- --next;
- }
- }
+ val.u = simple_strntoull(str,
+ field_width > 0 ? field_width : UINT_MAX,
+ &next, base);
switch (qualifier) {
case 'H': /* that's 'hh' in format */
--
2.20.1
Adds a wrapper shell script for the test_scanf module.
Signed-off-by: Richard Fitzgerald <[email protected]>
---
tools/testing/selftests/lib/Makefile | 2 +-
tools/testing/selftests/lib/config | 1 +
tools/testing/selftests/lib/scanf.sh | 4 ++++
3 files changed, 6 insertions(+), 1 deletion(-)
create mode 100755 tools/testing/selftests/lib/scanf.sh
diff --git a/tools/testing/selftests/lib/Makefile b/tools/testing/selftests/lib/Makefile
index a105f094676e..ee71fc99d5b5 100644
--- a/tools/testing/selftests/lib/Makefile
+++ b/tools/testing/selftests/lib/Makefile
@@ -4,6 +4,6 @@
# No binaries, but make sure arg-less "make" doesn't trigger "run_tests"
all:
-TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh strscpy.sh
+TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh scanf.sh strscpy.sh
include ../lib.mk
diff --git a/tools/testing/selftests/lib/config b/tools/testing/selftests/lib/config
index b80ee3f6e265..776c8c42e78d 100644
--- a/tools/testing/selftests/lib/config
+++ b/tools/testing/selftests/lib/config
@@ -1,4 +1,5 @@
CONFIG_TEST_PRINTF=m
+CONFIG_TEST_SCANTF=m
CONFIG_TEST_BITMAP=m
CONFIG_PRIME_NUMBERS=m
CONFIG_TEST_STRSCPY=m
diff --git a/tools/testing/selftests/lib/scanf.sh b/tools/testing/selftests/lib/scanf.sh
new file mode 100755
index 000000000000..b59b8ba561c3
--- /dev/null
+++ b/tools/testing/selftests/lib/scanf.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Tests the scanf infrastructure using test_scanf kernel module.
+$(dirname $0)/../kselftest/module.sh "scanf" test_scanf
--
2.20.1
Adds the new scanf test to the VSPRINTF group.
Signed-off-by: Richard Fitzgerald <[email protected]>
---
MAINTAINERS | 1 +
1 file changed, 1 insertion(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 7887d2161be4..d2bf38bd3d0c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18782,6 +18782,7 @@ S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk.git
F: Documentation/core-api/printk-formats.rst
F: lib/test_printf.c
+F: lib/test_scanf.c
F: lib/vsprintf.c
VT1211 HARDWARE MONITOR DRIVER
--
2.20.1
Adds test_sscanf to test various number conversion cases, as
number conversion was previously broken.
This also tests the simple_strtoxxx() functions exported from
vsprintf.c.
Signed-off-by: Richard Fitzgerald <[email protected]>
---
lib/Kconfig.debug | 3 +
lib/Makefile | 1 +
lib/test_scanf.c | 747 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 751 insertions(+)
create mode 100644 lib/test_scanf.c
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index c789b39ed527..b934dca35a0c 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2054,6 +2054,9 @@ config TEST_KSTRTOX
config TEST_PRINTF
tristate "Test printf() family of functions at runtime"
+config TEST_SCANF
+ tristate "Test scanf() family of functions at runtime"
+
config TEST_BITMAP
tristate "Test bitmap_*() family of functions at runtime"
help
diff --git a/lib/Makefile b/lib/Makefile
index ce45af50983a..091463b8986a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -85,6 +85,7 @@ obj-$(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-$(CONFIG_TEST_PRINTF) += test_printf.o
+obj-$(CONFIG_TEST_SCANF) += test_scanf.o
obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
obj-$(CONFIG_TEST_STRSCPY) += test_strscpy.o
obj-$(CONFIG_TEST_UUID) += test_uuid.o
diff --git a/lib/test_scanf.c b/lib/test_scanf.c
new file mode 100644
index 000000000000..96d22d83a7dd
--- /dev/null
+++ b/lib/test_scanf.c
@@ -0,0 +1,747 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test cases for sscanf facility.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/overflow.h>
+#include <linux/printk.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include "../tools/testing/selftests/kselftest_module.h"
+
+#define BUF_SIZE 1024
+
+static unsigned total_tests __initdata;
+static unsigned failed_tests __initdata;
+static char *test_buffer __initdata;
+static char *fmt_buffer __initdata;
+static struct rnd_state rnd_state __initdata;
+
+typedef int (*check_fn)(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap);
+
+static void __scanf(4, 6) __init
+_test(check_fn fn, const void *check_data, const char *string, const char *fmt,
+ int n_args, ...)
+{
+ va_list ap, ap_copy;
+ int ret;
+
+ total_tests++;
+
+ va_start(ap, n_args);
+ va_copy(ap_copy, ap);
+ ret = vsscanf(string, fmt, ap_copy);
+ va_end(ap_copy);
+
+ if (ret != n_args) {
+ pr_warn("vsscanf(\"%s\", \"%s\", ...) returned %d expected %d\n",
+ string, fmt, ret, n_args);
+ goto fail;
+ }
+
+ ret = (*fn)(check_data, string, fmt, n_args, ap);
+ if (ret)
+ goto fail;
+
+ va_end(ap);
+
+ return;
+
+fail:
+ failed_tests++;
+ va_end(ap);
+}
+
+#define _check_numbers_template(arg_fmt, expect, str, fmt, n_args, ap) \
+do { \
+ pr_debug("\"%s\", \"%s\" ->\n", str, fmt); \
+ for (; n_args > 0; --n_args, ++expect) { \
+ typeof(*expect) got = *va_arg(ap, typeof(expect)); \
+ pr_debug("\t" arg_fmt "\n", got); \
+ if (got != *expect) { \
+ pr_warn("vsscanf(\"%s\", \"%s\", ...) expected " arg_fmt " got " arg_fmt "\n", \
+ str, fmt, *expect, got); \
+ return 1; \
+ } \
+ } \
+ return 0; \
+} while (0)
+
+static int __init check_ull(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const unsigned long long *pval = check_data;
+
+ _check_numbers_template("%llu", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_ll(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const long long *pval = check_data;
+
+ _check_numbers_template("%lld", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_ulong(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const unsigned long *pval = check_data;
+
+ _check_numbers_template("%lu", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_long(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const long *pval = check_data;
+
+ _check_numbers_template("%ld", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_uint(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const unsigned int *pval = check_data;
+
+ _check_numbers_template("%u", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_int(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const int *pval = check_data;
+
+ _check_numbers_template("%d", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_ushort(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const unsigned short *pval = check_data;
+
+ _check_numbers_template("%hu", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_short(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const short *pval = check_data;
+
+ _check_numbers_template("%hd", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_uchar(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const unsigned char *pval = check_data;
+
+ _check_numbers_template("%hhu", pval, string, fmt, n_args, ap);
+}
+
+static int __init check_char(const void *check_data, const char *string,
+ const char *fmt, int n_args, va_list ap)
+{
+ const signed char *pval = check_data;
+
+ _check_numbers_template("%hhd", pval, string, fmt, n_args, ap);
+}
+
+/* Selection of interesting numbers to test, copied from test-kstrtox.c */
+static const unsigned long long numbers[] __initconst = {
+ 0x0ULL,
+ 0x1ULL,
+ 0x7fULL,
+ 0x80ULL,
+ 0x81ULL,
+ 0xffULL,
+ 0x100ULL,
+ 0x101ULL,
+ 0x7fffULL,
+ 0x8000ULL,
+ 0x8001ULL,
+ 0xffffULL,
+ 0x10000ULL,
+ 0x10001ULL,
+ 0x7fffffffULL,
+ 0x80000000ULL,
+ 0x80000001ULL,
+ 0xffffffffULL,
+ 0x100000000ULL,
+ 0x100000001ULL,
+ 0x7fffffffffffffffULL,
+ 0x8000000000000000ULL,
+ 0x8000000000000001ULL,
+ 0xfffffffffffffffeULL,
+ 0xffffffffffffffffULL,
+};
+
+#define value_representable_in_type(T, val) \
+(is_signed_type(T) \
+ ? ((long long)(val) >= type_min(T)) && ((long long)(val) <= type_max(T)) \
+ : ((unsigned long long)(val) >= type_min(T)) && \
+ ((unsigned long long)(val) <= type_max(T)))
+
+#define test_one_number(T, gen_fmt, scan_fmt, val, fn) \
+do { \
+ const T expect_val = (T)(val); \
+ T result = ~expect_val; /* should be overwritten */ \
+ \
+ snprintf(test_buffer, BUF_SIZE, gen_fmt, expect_val); \
+ _test(fn, &expect_val, test_buffer, "%" scan_fmt, 1, &result); \
+} while (0)
+
+#define simple_numbers_loop(T, gen_fmt, scan_fmt, fn) \
+do { \
+ int i; \
+ \
+ for (i = 0; i < ARRAY_SIZE(numbers); ++i) { \
+ if (!value_representable_in_type(T, numbers[i])) \
+ continue; \
+ \
+ test_one_number(T, gen_fmt, scan_fmt, numbers[i], fn); \
+ \
+ if (is_signed_type(T)) \
+ test_one_number(T, gen_fmt, scan_fmt, \
+ -numbers[i], fn); \
+ } \
+} while (0)
+
+static void __init numbers_simple(void)
+{
+ simple_numbers_loop(unsigned long long, "%llu", "llu", check_ull);
+ simple_numbers_loop(long long, "%lld", "lld", check_ll);
+ simple_numbers_loop(long long, "%lld", "lli", check_ll);
+ simple_numbers_loop(unsigned long long, "%llx", "llx", check_ull);
+ simple_numbers_loop(long long, "%llx", "llx", check_ll);
+ simple_numbers_loop(long long, "0x%llx", "lli", check_ll);
+ simple_numbers_loop(unsigned long long, "0x%llx", "llx", check_ull);
+ simple_numbers_loop(long long, "0x%llx", "llx", check_ll);
+
+ simple_numbers_loop(unsigned long, "%lu", "lu", check_ulong);
+ simple_numbers_loop(long, "%ld", "ld", check_long);
+ simple_numbers_loop(long, "%ld", "li", check_long);
+ simple_numbers_loop(unsigned long, "%lx", "lx", check_ulong);
+ simple_numbers_loop(long, "%lx", "lx", check_long);
+ simple_numbers_loop(long, "0x%lx", "li", check_long);
+ simple_numbers_loop(unsigned long, "0x%lx", "lx", check_ulong);
+ simple_numbers_loop(long, "0x%lx", "lx", check_long);
+
+ simple_numbers_loop(unsigned int, "%u", "u", check_uint);
+ simple_numbers_loop(int, "%d", "d", check_int);
+ simple_numbers_loop(int, "%d", "i", check_int);
+ simple_numbers_loop(unsigned int, "%x", "x", check_uint);
+ simple_numbers_loop(int, "%x", "x", check_int);
+ simple_numbers_loop(int, "0x%x", "i", check_int);
+ simple_numbers_loop(unsigned int, "0x%x", "x", check_uint);
+ simple_numbers_loop(int, "0x%x", "x", check_int);
+
+ simple_numbers_loop(unsigned short, "%hu", "hu", check_ushort);
+ simple_numbers_loop(short, "%hd", "hd", check_short);
+ simple_numbers_loop(short, "%hd", "hi", check_short);
+ simple_numbers_loop(unsigned short, "%hx", "hx", check_ushort);
+ simple_numbers_loop(short, "%hx", "hx", check_short);
+ simple_numbers_loop(short, "0x%hx", "hi", check_short);
+ simple_numbers_loop(unsigned short, "0x%hx", "hx", check_ushort);
+ simple_numbers_loop(short, "0x%hx", "hx", check_short);
+
+ simple_numbers_loop(unsigned char, "%hhu", "hhu", check_uchar);
+ simple_numbers_loop(signed char, "%hhd", "hhd", check_char);
+ simple_numbers_loop(signed char, "%hhd", "hhi", check_char);
+ simple_numbers_loop(unsigned char, "%hhx", "hhx", check_uchar);
+ simple_numbers_loop(signed char, "%hhx", "hhx", check_char);
+ simple_numbers_loop(signed char, "0x%hhx", "hhi", check_char);
+ simple_numbers_loop(unsigned char, "0x%hhx", "hhx", check_uchar);
+ simple_numbers_loop(signed char, "0x%hhx", "hhx", check_char);
+}
+
+/*
+ * This gives a better variety of number "lengths" in a small sample than
+ * the raw prandom*() functions (Not mathematically rigorous!!).
+ * Variabilty of length and value is more important than perfect randomness.
+ */
+static u32 __init next_test_random(u32 max_bits)
+{
+ u32 n_bits = hweight32(prandom_u32_state(&rnd_state)) % (max_bits + 1);
+
+ return prandom_u32_state(&rnd_state) & (UINT_MAX >> (32 - n_bits));
+}
+
+static unsigned long long __init next_test_random_ull(void)
+{
+ u32 rand1 = prandom_u32_state(&rnd_state);
+ u32 n_bits = (hweight32(rand1) * 3) % 64;
+ u64 val = (u64)prandom_u32_state(&rnd_state) * rand1;
+
+ return val & (ULLONG_MAX >> (64 - n_bits));
+}
+
+#define random_for_type(T) \
+ ((T)(sizeof(T) <= sizeof(u32) \
+ ? next_test_random(BITS_PER_TYPE(T)) \
+ : next_test_random_ull()))
+
+/*
+ * Define a pattern of negative and positive numbers to ensure we get
+ * some of both within the small number of samples in a test string.
+ */
+#define NEGATIVES_PATTERN 0x3246 /* 00110010 01000110 */
+
+#define fill_random_array(arr) \
+do { \
+ unsigned int neg_pattern = NEGATIVES_PATTERN; \
+ int i; \
+ \
+ for (i = 0; i < ARRAY_SIZE(arr); ++i, neg_pattern >>= 1) { \
+ (arr)[i] = random_for_type(typeof((arr)[0])); \
+ if (is_signed_type(typeof((arr)[0])) && (neg_pattern & 1)) \
+ (arr)[i] = -(arr)[i]; \
+ } \
+} while (0)
+
+/*
+ * Convenience wrapper around snprintf() to append at buf_pos in buf,
+ * updating buf_pos and returning the number of characters appended.
+ * On error buf_pos is not changed and return value is 0.
+ */
+static int __init __printf(4, 5)
+append_fmt(char *buf, int *buf_pos, int buf_len, const char *val_fmt, ...)
+{
+ va_list ap;
+ int field_len;
+
+ va_start(ap, val_fmt);
+ field_len = vsnprintf(buf + *buf_pos, buf_len - *buf_pos, val_fmt, ap);
+ va_end(ap);
+
+ if (field_len < 0)
+ field_len = 0;
+
+ *buf_pos += field_len;
+
+ return field_len;
+}
+
+/*
+ * Convenience function to append the field delimiter string
+ * to both the value string and format string buffers.
+ */
+static void __init append_delim(char *str_buf, int *str_buf_pos, int str_buf_len,
+ char *fmt_buf, int *fmt_buf_pos, int fmt_buf_len,
+ const char *delim_str)
+{
+ append_fmt(str_buf, str_buf_pos, str_buf_len, delim_str);
+ append_fmt(fmt_buf, fmt_buf_pos, fmt_buf_len, delim_str);
+}
+
+#define test_array_8(fn, check_data, string, fmt, arr) \
+do { \
+ BUILD_BUG_ON(ARRAY_SIZE(arr) != 8); \
+ _test(fn, check_data, string, fmt, 8, \
+ &(arr)[0], &(arr)[1], &(arr)[2], &(arr)[3], \
+ &(arr)[4], &(arr)[5], &(arr)[6], &(arr)[7]); \
+} while (0)
+
+#define numbers_list_8(T, gen_fmt, field_sep, scan_fmt, fn) \
+do { \
+ int i, pos = 0, fmt_pos = 0; \
+ T expect[8], result[8]; \
+ \
+ fill_random_array(expect); \
+ \
+ for (i = 0; i < ARRAY_SIZE(expect); ++i) { \
+ if (i != 0) \
+ append_delim(test_buffer, &pos, BUF_SIZE, \
+ fmt_buffer, &fmt_pos, BUF_SIZE, \
+ field_sep); \
+ \
+ append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt, expect[i]); \
+ append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE, "%%%s", scan_fmt); \
+ } \
+ \
+ test_array_8(fn, expect, test_buffer, fmt_buffer, result); \
+} while (0)
+
+#define numbers_list_fix_width(T, gen_fmt, field_sep, width, scan_fmt, fn) \
+do { \
+ char full_fmt[16]; \
+ \
+ snprintf(full_fmt, sizeof(full_fmt), "%u%s", width, scan_fmt); \
+ numbers_list_8(T, gen_fmt, field_sep, full_fmt, fn); \
+} while (0)
+
+#define numbers_list_val_width(T, gen_fmt, field_sep, scan_fmt, fn) \
+do { \
+ int i, val_len, pos = 0, fmt_pos = 0; \
+ T expect[8], result[8]; \
+ \
+ fill_random_array(expect); \
+ \
+ for (i = 0; i < ARRAY_SIZE(expect); ++i) { \
+ if (i != 0) \
+ append_delim(test_buffer, &pos, BUF_SIZE, \
+ fmt_buffer, &fmt_pos, BUF_SIZE, field_sep);\
+ \
+ val_len = append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt, \
+ expect[i]); \
+ append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE, \
+ "%%%u%s", val_len, scan_fmt); \
+ } \
+ \
+ test_array_8(fn, expect, test_buffer, fmt_buffer, result); \
+} while (0)
+
+static void __init numbers_list(const char *delim)
+{
+ numbers_list_8(unsigned long long, "%llu", delim, "llu", check_ull);
+ numbers_list_8(long long, "%lld", delim, "lld", check_ll);
+ numbers_list_8(long long, "%lld", delim, "lli", check_ll);
+ numbers_list_8(unsigned long long, "%llx", delim, "llx", check_ull);
+ numbers_list_8(unsigned long long, "0x%llx", delim, "llx", check_ull);
+ numbers_list_8(long long, "0x%llx", delim, "lli", check_ll);
+
+ numbers_list_8(unsigned long, "%lu", delim, "lu", check_ulong);
+ numbers_list_8(long, "%ld", delim, "ld", check_long);
+ numbers_list_8(long, "%ld", delim, "li", check_long);
+ numbers_list_8(unsigned long, "%lx", delim, "lx", check_ulong);
+ numbers_list_8(unsigned long, "0x%lx", delim, "lx", check_ulong);
+ numbers_list_8(long, "0x%lx", delim, "li", check_long);
+
+ numbers_list_8(unsigned int, "%u", delim, "u", check_uint);
+ numbers_list_8(int, "%d", delim, "d", check_int);
+ numbers_list_8(int, "%d", delim, "i", check_int);
+ numbers_list_8(unsigned int, "%x", delim, "x", check_uint);
+ numbers_list_8(unsigned int, "0x%x", delim, "x", check_uint);
+ numbers_list_8(int, "0x%x", delim, "i", check_int);
+
+ numbers_list_8(unsigned short, "%hu", delim, "hu", check_ushort);
+ numbers_list_8(short, "%hd", delim, "hd", check_short);
+ numbers_list_8(short, "%hd", delim, "hi", check_short);
+ numbers_list_8(unsigned short, "%hx", delim, "hx", check_ushort);
+ numbers_list_8(unsigned short, "0x%hx", delim, "hx", check_ushort);
+ numbers_list_8(short, "0x%hx", delim, "hi", check_short);
+
+ numbers_list_8(unsigned char, "%hhu", delim, "hhu", check_uchar);
+ numbers_list_8(signed char, "%hhd", delim, "hhd", check_char);
+ numbers_list_8(signed char, "%hhd", delim, "hhi", check_char);
+ numbers_list_8(unsigned char, "%hhx", delim, "hhx", check_uchar);
+ numbers_list_8(unsigned char, "0x%hhx", delim, "hhx", check_uchar);
+ numbers_list_8(signed char, "0x%hhx", delim, "hhi", check_char);
+}
+
+/*
+ * List of numbers separated by delim. Each field width specifier is the
+ * maximum possible digits for the given type and base.
+ */
+static void __init numbers_list_field_width_typemax(const char *delim)
+{
+ numbers_list_fix_width(unsigned long long, "%llu", delim, 20, "llu", check_ull);
+ numbers_list_fix_width(long long, "%lld", delim, 20, "lld", check_ll);
+ numbers_list_fix_width(long long, "%lld", delim, 20, "lli", check_ll);
+ numbers_list_fix_width(unsigned long long, "%llx", delim, 16, "llx", check_ull);
+ numbers_list_fix_width(unsigned long long, "0x%llx", delim, 18, "llx", check_ull);
+ numbers_list_fix_width(long long, "0x%llx", delim, 18, "lli", check_ll);
+
+#if BITS_PER_LONG == 64
+ numbers_list_fix_width(unsigned long, "%lu", delim, 20, "lu", check_ulong);
+ numbers_list_fix_width(long, "%ld", delim, 20, "ld", check_long);
+ numbers_list_fix_width(long, "%ld", delim, 20, "li", check_long);
+ numbers_list_fix_width(unsigned long, "%lx", delim, 16, "lx", check_ulong);
+ numbers_list_fix_width(unsigned long, "0x%lx", delim, 18, "lx", check_ulong);
+ numbers_list_fix_width(long, "0x%lx", delim, 18, "li", check_long);
+#else
+ numbers_list_fix_width(unsigned long, "%lu", delim, 10, "lu", check_ulong);
+ numbers_list_fix_width(long, "%ld", delim, 11, "ld", check_long);
+ numbers_list_fix_width(long, "%ld", delim, 11, "li", check_long);
+ numbers_list_fix_width(unsigned long, "%lx", delim, 8, "lx", check_ulong);
+ numbers_list_fix_width(unsigned long, "0x%lx", delim, 10, "lx", check_ulong);
+ numbers_list_fix_width(long, "0x%lx", delim, 10, "li", check_long);
+#endif
+
+ numbers_list_fix_width(unsigned int, "%u", delim, 10, "u", check_uint);
+ numbers_list_fix_width(int, "%d", delim, 11, "d", check_int);
+ numbers_list_fix_width(int, "%d", delim, 11, "i", check_int);
+ numbers_list_fix_width(unsigned int, "%x", delim, 8, "x", check_uint);
+ numbers_list_fix_width(unsigned int, "0x%x", delim, 10, "x", check_uint);
+ numbers_list_fix_width(int, "0x%x", delim, 10, "i", check_int);
+
+ numbers_list_fix_width(unsigned short, "%hu", delim, 5, "hu", check_ushort);
+ numbers_list_fix_width(short, "%hd", delim, 6, "hd", check_short);
+ numbers_list_fix_width(short, "%hd", delim, 6, "hi", check_short);
+ numbers_list_fix_width(unsigned short, "%hx", delim, 4, "hx", check_ushort);
+ numbers_list_fix_width(unsigned short, "0x%hx", delim, 6, "hx", check_ushort);
+ numbers_list_fix_width(short, "0x%hx", delim, 6, "hi", check_short);
+
+ numbers_list_fix_width(unsigned char, "%hhu", delim, 3, "hhu", check_uchar);
+ numbers_list_fix_width(signed char, "%hhd", delim, 4, "hhd", check_char);
+ numbers_list_fix_width(signed char, "%hhd", delim, 4, "hhi", check_char);
+ numbers_list_fix_width(unsigned char, "%hhx", delim, 2, "hhx", check_uchar);
+ numbers_list_fix_width(unsigned char, "0x%hhx", delim, 4, "hhx", check_uchar);
+ numbers_list_fix_width(signed char, "0x%hhx", delim, 4, "hhi", check_char);
+}
+
+/*
+ * List of numbers separated by delim. Each field width specifier is the
+ * exact length of the corresponding value digits in the string being scanned.
+ */
+static void __init numbers_list_field_width_val_width(const char *delim)
+{
+ numbers_list_val_width(unsigned long long, "%llu", delim, "llu", check_ull);
+ numbers_list_val_width(long long, "%lld", delim, "lld", check_ll);
+ numbers_list_val_width(long long, "%lld", delim, "lli", check_ll);
+ numbers_list_val_width(unsigned long long, "%llx", delim, "llx", check_ull);
+ numbers_list_val_width(unsigned long long, "0x%llx", delim, "llx", check_ull);
+ numbers_list_val_width(long long, "0x%llx", delim, "lli", check_ll);
+
+ numbers_list_val_width(unsigned long, "%lu", delim, "lu", check_ulong);
+ numbers_list_val_width(long, "%ld", delim, "ld", check_long);
+ numbers_list_val_width(long, "%ld", delim, "li", check_long);
+ numbers_list_val_width(unsigned long, "%lx", delim, "lx", check_ulong);
+ numbers_list_val_width(unsigned long, "0x%lx", delim, "lx", check_ulong);
+ numbers_list_val_width(long, "0x%lx", delim, "li", check_long);
+
+ numbers_list_val_width(unsigned int, "%u", delim, "u", check_uint);
+ numbers_list_val_width(int, "%d", delim, "d", check_int);
+ numbers_list_val_width(int, "%d", delim, "i", check_int);
+ numbers_list_val_width(unsigned int, "%x", delim, "x", check_uint);
+ numbers_list_val_width(unsigned int, "0x%x", delim, "x", check_uint);
+ numbers_list_val_width(int, "0x%x", delim, "i", check_int);
+
+ numbers_list_val_width(unsigned short, "%hu", delim, "hu", check_ushort);
+ numbers_list_val_width(short, "%hd", delim, "hd", check_short);
+ numbers_list_val_width(short, "%hd", delim, "hi", check_short);
+ numbers_list_val_width(unsigned short, "%hx", delim, "hx", check_ushort);
+ numbers_list_val_width(unsigned short, "0x%hx", delim, "hx", check_ushort);
+ numbers_list_val_width(short, "0x%hx", delim, "hi", check_short);
+
+ numbers_list_val_width(unsigned char, "%hhu", delim, "hhu", check_uchar);
+ numbers_list_val_width(signed char, "%hhd", delim, "hhd", check_char);
+ numbers_list_val_width(signed char, "%hhd", delim, "hhi", check_char);
+ numbers_list_val_width(unsigned char, "%hhx", delim, "hhx", check_uchar);
+ numbers_list_val_width(unsigned char, "0x%hhx", delim, "hhx", check_uchar);
+ numbers_list_val_width(signed char, "0x%hhx", delim, "hhi", check_char);
+}
+
+/*
+ * Slice a continuous string of digits without field delimiters, containing
+ * numbers of varying length, using the field width to extract each group
+ * of digits. For example the hex values c0,3,bf01,303 would have a
+ * string representation of "c03bf01303" and extracted with "%2x%1x%4x%3x".
+ */
+static void __init numbers_slice(void)
+{
+ numbers_list_field_width_val_width("");
+}
+
+#define test_number_prefix(T, str, scan_fmt, expect0, expect1, n_args, fn) \
+do { \
+ const T expect[2] = { expect0, expect1 }; \
+ T result[2] = {~expect[0], ~expect[1]}; \
+ \
+ _test(fn, &expect, str, scan_fmt, n_args, &result[0], &result[1]); \
+} while (0)
+
+/*
+ * Number prefix is >= field width.
+ * Expected behaviour is derived from testing userland sscanf.
+ */
+static void __init numbers_prefix_overflow(void)
+{
+ /*
+ * Negative decimal with a field of width 1, should quit scanning
+ * and return 0.
+ */
+ test_number_prefix(long long, "-1 1", "%1lld %lld", 0, 0, 0, check_ll);
+ test_number_prefix(long, "-1 1", "%1ld %ld", 0, 0, 0, check_long);
+ test_number_prefix(int, "-1 1", "%1d %d", 0, 0, 0, check_int);
+ test_number_prefix(short, "-1 1", "%1hd %hd", 0, 0, 0, check_short);
+ test_number_prefix(signed char, "-1 1", "%1hhd %hhd", 0, 0, 0, check_char);
+
+ test_number_prefix(long long, "-1 1", "%1lli %lli", 0, 0, 0, check_ll);
+ test_number_prefix(long, "-1 1", "%1li %li", 0, 0, 0, check_long);
+ test_number_prefix(int, "-1 1", "%1i %i", 0, 0, 0, check_int);
+ test_number_prefix(short, "-1 1", "%1hi %hi", 0, 0, 0, check_short);
+ test_number_prefix(signed char, "-1 1", "%1hhi %hhi", 0, 0, 0, check_char);
+
+ /*
+ * 0x prefix in a field of width 1: 0 is a valid digit so should
+ * convert. Next field scan starts at the 'x' which isn't a digit so
+ * scan quits with one field converted.
+ */
+ test_number_prefix(unsigned long long, "0xA7", "%1llx%llx", 0, 0, 1, check_ull);
+ test_number_prefix(unsigned long, "0xA7", "%1lx%lx", 0, 0, 1, check_ulong);
+ test_number_prefix(unsigned int, "0xA7", "%1x%x", 0, 0, 1, check_uint);
+ test_number_prefix(unsigned short, "0xA7", "%1hx%hx", 0, 0, 1, check_ushort);
+ test_number_prefix(unsigned char, "0xA7", "%1hhx%hhx", 0, 0, 1, check_uchar);
+ test_number_prefix(long long, "0xA7", "%1lli%llx", 0, 0, 1, check_ll);
+ test_number_prefix(long, "0xA7", "%1li%lx", 0, 0, 1, check_long);
+ test_number_prefix(int, "0xA7", "%1i%x", 0, 0, 1, check_int);
+ test_number_prefix(short, "0xA7", "%1hi%hx", 0, 0, 1, check_short);
+ test_number_prefix(char, "0xA7", "%1hhi%hhx", 0, 0, 1, check_char);
+
+ /*
+ * 0x prefix in a field of width 2 using %x conversion: first field
+ * converts to 0. Next field scan starts at the character after "0x".
+ * Both fields will convert.
+ */
+ test_number_prefix(unsigned long long, "0xA7", "%2llx%llx", 0, 0xa7, 2, check_ull);
+ test_number_prefix(unsigned long, "0xA7", "%2lx%lx", 0, 0xa7, 2, check_ulong);
+ test_number_prefix(unsigned int, "0xA7", "%2x%x", 0, 0xa7, 2, check_uint);
+ test_number_prefix(unsigned short, "0xA7", "%2hx%hx", 0, 0xa7, 2, check_ushort);
+ test_number_prefix(unsigned char, "0xA7", "%2hhx%hhx", 0, 0xa7, 2, check_uchar);
+
+ /*
+ * 0x prefix in a field of width 2 using %i conversion: first field
+ * converts to 0. Next field scan starts at the character after "0x",
+ * which will convert if can be intepreted as decimal but will fail
+ * if it contains any hex digits (since no 0x prefix).
+ */
+ test_number_prefix(long long, "0x67", "%2lli%lli", 0, 67, 2, check_ll);
+ test_number_prefix(long, "0x67", "%2li%li", 0, 67, 2, check_long);
+ test_number_prefix(int, "0x67", "%2i%i", 0, 67, 2, check_int);
+ test_number_prefix(short, "0x67", "%2hi%hi", 0, 67, 2, check_short);
+ test_number_prefix(char, "0x67", "%2hhi%hhi", 0, 67, 2, check_char);
+
+ test_number_prefix(long long, "0xA7", "%2lli%lli", 0, 0, 1, check_ll);
+ test_number_prefix(long, "0xA7", "%2li%li", 0, 0, 1, check_long);
+ test_number_prefix(int, "0xA7", "%2i%i", 0, 0, 1, check_int);
+ test_number_prefix(short, "0xA7", "%2hi%hi", 0, 0, 1, check_short);
+ test_number_prefix(char, "0xA7", "%2hhi%hhi", 0, 0, 1, check_char);
+}
+
+#define _test_simple_strtoxx(T, fn, gen_fmt, expect, base) \
+do { \
+ T got; \
+ char *endp; \
+ int len; \
+ bool fail = false; \
+ \
+ ++total_tests; \
+ len = snprintf(test_buffer, BUF_SIZE, gen_fmt, expect); \
+ got = (fn)(test_buffer, &endp, base); \
+ pr_debug(#fn "(\"%s\", %d) -> " gen_fmt "\n", test_buffer, base, got); \
+ if (got != (expect)) { \
+ fail = true; \
+ pr_warn(#fn "(\"%s\", %d): got " gen_fmt " expected " gen_fmt "\n", \
+ test_buffer, base, got, expect); \
+ } else if (endp != test_buffer + len) { \
+ fail = true; \
+ pr_warn(#fn "(\"%s\", %d) startp=0x%px got endp=0x%px expected 0x%px\n", \
+ test_buffer, base, test_buffer, \
+ test_buffer + len, endp); \
+ } \
+ \
+ if (fail) \
+ ++failed_tests; \
+} while (0)
+
+#define test_simple_strtoxx(T, fn, gen_fmt, base) \
+do { \
+ int i; \
+ \
+ for (i = 0; i < ARRAY_SIZE(numbers); ++i) { \
+ _test_simple_strtoxx(T, fn, gen_fmt, (T)numbers[i], base); \
+ \
+ if (is_signed_type(T)) \
+ _test_simple_strtoxx(T, fn, gen_fmt, \
+ -(T)numbers[i], base); \
+ } \
+} while (0)
+
+static void __init test_simple_strtoull(void)
+{
+ test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu", 10);
+ test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu", 0);
+ test_simple_strtoxx(unsigned long long, simple_strtoull, "%llx", 16);
+ test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 16);
+ test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 0);
+}
+
+static void __init test_simple_strtoll(void)
+{
+ test_simple_strtoxx(long long, simple_strtoll, "%lld", 10);
+ test_simple_strtoxx(long long, simple_strtoll, "%lld", 0);
+ test_simple_strtoxx(long long, simple_strtoll, "%llx", 16);
+ test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 16);
+ test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 0);
+}
+
+static void __init test_simple_strtoul(void)
+{
+ test_simple_strtoxx(unsigned long, simple_strtoul, "%lu", 10);
+ test_simple_strtoxx(unsigned long, simple_strtoul, "%lu", 0);
+ test_simple_strtoxx(unsigned long, simple_strtoul, "%lx", 16);
+ test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 16);
+ test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 0);
+}
+
+static void __init test_simple_strtol(void)
+{
+ test_simple_strtoxx(long, simple_strtol, "%ld", 10);
+ test_simple_strtoxx(long, simple_strtol, "%ld", 0);
+ test_simple_strtoxx(long, simple_strtol, "%lx", 16);
+ test_simple_strtoxx(long, simple_strtol, "0x%lx", 16);
+ test_simple_strtoxx(long, simple_strtol, "0x%lx", 0);
+}
+
+/* Selection of common delimiters/separators between numbers in a string. */
+static const char * const number_delimiters[] __initconst = {
+ " ", ":", ",", "-", "/",
+};
+
+static void __init test_numbers(void)
+{
+ int i;
+
+ /* String containing only one number. */
+ numbers_simple();
+
+ /* String with multiple numbers separated by delimiter. */
+ for (i = 0; i < ARRAY_SIZE(number_delimiters); ++i) {
+ numbers_list(number_delimiters[i]);
+
+ /* Field width may be longer than actual field digits. */
+ numbers_list_field_width_typemax(number_delimiters[i]);
+
+ /* Each field width exactly length of actual field digits. */
+ numbers_list_field_width_val_width(number_delimiters[i]);
+ }
+
+ /* Slice continuous sequence of digits using field widths. */
+ numbers_slice();
+
+ numbers_prefix_overflow();
+}
+
+static void __init selftest(void)
+{
+ test_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
+ if (!test_buffer)
+ return;
+
+ fmt_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
+ if (!fmt_buffer)
+ return;
+
+ prandom_seed_state(&rnd_state, 3141592653589793238ULL);
+
+ test_numbers();
+
+ test_simple_strtoull();
+ test_simple_strtoll();
+ test_simple_strtoul();
+ test_simple_strtol();
+}
+
+KSTM_MODULE_LOADERS(test_scanf);
+MODULE_AUTHOR("Richard Fitzgerald <[email protected]>");
+MODULE_LICENSE("GPL v2");
--
2.20.1
On Mon 2020-11-30 14:57:57, Richard Fitzgerald wrote:
> The existing code attempted to handle numbers by doing a strto[u]l(),
> ignoring the field width, and then bitshifting the field out of the
> converted value. If the string contains a run of valid digits longer
> than will fit in a long or long long, this would overflow and no amount
> of bitshifting can recover the correct value.
>
> This patch fixes vsscanf to obey number field widths when parsing
> the number.
>
> A new _parse_integer_limit() is added that takes a limit for the number
> of characters to parse. The number field conversion in vsscanf is changed
> to use this new function.
>
> The cases of a base prefix or leading '-' that is >= the maximum
> field
I have troubles to parse this sentence. It might be because I am
not a native speaker.
> width is handled such that the result of a sccanf is consistent with the
> observed behaviour of userland sscanf.
Anyway, it would be great to explain this on few examples that describe
the corner cases. See also below.
> --- a/lib/kstrtox.c
> +++ b/lib/kstrtox.c
> @@ -39,20 +39,22 @@ const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
>
> /*
> * Convert non-negative integer string representation in explicitly given radix
> - * to an integer.
> + * to an integer. A maximum of max_chars characters will be converted.
> + *
> * Return number of characters consumed maybe or-ed with overflow bit.
> * If overflow occurs, result integer (incorrect) is still returned.
> *
> * Don't you dare use this function.
> */
> -unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
> +unsigned int _parse_integer_limit(const char *s, unsigned int base,
> + unsigned long long *p, size_t max_chars)
> {
> unsigned long long res;
> unsigned int rv;
>
> res = 0;
> rv = 0;
> - while (1) {
> + for (; max_chars > 0; max_chars--) {
> unsigned int c = *s;
> unsigned int lc = c | 0x20; /* don't tolower() this line */
> unsigned int val;
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 14c9a6af1b23..21145da468e0 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -53,29 +53,47 @@
> #include <linux/string_helpers.h>
> #include "kstrtox.h"
>
> -/**
> - * simple_strtoull - convert a string to an unsigned long long
> - * @cp: The start of the string
> - * @endp: A pointer to the end of the parsed string will be placed here
> - * @base: The number base to use
> - *
> - * This function has caveats. Please use kstrtoull instead.
> - */
> -unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
> +static unsigned long long simple_strntoull(const char *startp, size_t max_chars,
> + char **endp, unsigned int base)
> {
> - unsigned long long result;
> + const char *cp;
> + unsigned long long result = 0ULL;
> unsigned int rv;
>
> - cp = _parse_integer_fixup_radix(cp, &base);
> - rv = _parse_integer(cp, base, &result);
> + if (max_chars == 0) {
> + cp = startp;
> + goto out;
> + }
> +
> + cp = _parse_integer_fixup_radix(startp, &base);
> + if ((cp - startp) >= max_chars) {
> + cp = startp + max_chars;
> + goto out;
> + }
> +
> + max_chars -= (cp - startp);
> + rv = _parse_integer_limit(cp, base, &result, max_chars);
> /* FIXME */
> cp += (rv & ~KSTRTOX_OVERFLOW);
> -
> +out:
> if (endp)
> *endp = (char *)cp;
>
> return result;
> }
> +
> +/**
> + * simple_strtoull - convert a string to an unsigned long long
> + * @cp: The start of the string
> + * @endp: A pointer to the end of the parsed string will be placed here
> + * @base: The number base to use
> + *
> + * This function has caveats. Please use kstrtoull instead.
> + */
> +unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
> +{
> + return simple_strntoull(cp, UINT_MAX, endp, base);
Please, use INT_MAX everywhere. It is an arbitrary big-enough number.
And INT_MAX is already used in vscnprintf().
> +}
> EXPORT_SYMBOL(simple_strtoull);
>
> /**
> @@ -88,7 +106,7 @@ EXPORT_SYMBOL(simple_strtoull);
> */
> unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
> {
> - return simple_strtoull(cp, endp, base);
> + return simple_strntoull(cp, UINT_MAX, endp, base);
Same here.
> }
> EXPORT_SYMBOL(simple_strtoul);
>
> @@ -109,6 +127,19 @@ long simple_strtol(const char *cp, char **endp, unsigned int base)
> }
> EXPORT_SYMBOL(simple_strtol);
>
> +static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
> + unsigned int base)
> +{
> + /*
> + * simple_strntoull safely handles receiving max_chars==0 in the
> + * case we start with max_chars==1 and find a '-' prefix.
> + */
> + if (*cp == '-' && max_chars > 0)
> + return -simple_strntoull(cp + 1, max_chars - 1, endp, base);
> +
> + return simple_strntoull(cp, max_chars, endp, base);
> +}
> +
> /**
> * simple_strtoll - convert a string to a signed long long
> * @cp: The start of the string
> @@ -119,10 +150,7 @@ EXPORT_SYMBOL(simple_strtol);
> */
> long long simple_strtoll(const char *cp, char **endp, unsigned int base)
> {
> - if (*cp == '-')
> - return -simple_strtoull(cp + 1, endp, base);
> -
> - return simple_strtoull(cp, endp, base);
> + return simple_strntoll(cp, UINT_MAX, endp, base);
And here.
> }
> EXPORT_SYMBOL(simple_strtoll);
>
> @@ -3433,8 +3461,11 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
> str = skip_spaces(str);
>
> digit = *str;
> - if (is_sign && digit == '-')
> + if (is_sign && digit == '-') {
> + if (field_width == 1)
> + break;
This should be handled in a separate patch. It is a subtle change that
is hidden deep inside a big diff.
1. It is quite hard to notice because the above simple_strntoll() was
implemented to return 0 in this case.
2. The commit message describes the situation when all read numbers
overflow unsigned long long. And this is another corner that
was not clearly mentioned.
> digit = *(str + 1);
> + }
>
> if (!digit
> || (base == 16 && !isxdigit(digit))
Otherwise, I really like patch. Thanks a lot for the effort.
I am sorry that it took me so long to look at it. I was pretty busy
last week. I am going to look at the huge 2nd patch tomorrow.
Best Regards,
Petr
On Mon 2020-11-30 14:57:58, Richard Fitzgerald wrote:
> Adds test_sscanf to test various number conversion cases, as
> number conversion was previously broken.
>
> This also tests the simple_strtoxxx() functions exported from
> vsprintf.c.
It is impressive.
Honestly, I do not feel to be expert on testing and mathematics.
I am not sure how comprehensive the test is. Also I am not
sure what experts would say about the tricks with random
numbers.
Anyway, this is much more than what I have expected. And it checks
great number of variants and corner cases.
I suggest only one small change, see below.
> --- /dev/null
> +++ b/lib/test_scanf.c
> @@ -0,0 +1,747 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Test cases for sscanf facility.
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/bitops.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/overflow.h>
> +#include <linux/printk.h>
> +#include <linux/random.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +
> +#include "../tools/testing/selftests/kselftest_module.h"
> +
> +#define BUF_SIZE 1024
> +
> +static unsigned total_tests __initdata;
> +static unsigned failed_tests __initdata;
> +static char *test_buffer __initdata;
> +static char *fmt_buffer __initdata;
> +static struct rnd_state rnd_state __initdata;
> +
> +typedef int (*check_fn)(const void *check_data, const char *string,
> + const char *fmt, int n_args, va_list ap);
> +
> +static void __scanf(4, 6) __init
> +_test(check_fn fn, const void *check_data, const char *string, const char *fmt,
> + int n_args, ...)
> +{
> + va_list ap, ap_copy;
> + int ret;
> +
> + total_tests++;
> +
> + va_start(ap, n_args);
> + va_copy(ap_copy, ap);
> + ret = vsscanf(string, fmt, ap_copy);
> + va_end(ap_copy);
> +
> + if (ret != n_args) {
> + pr_warn("vsscanf(\"%s\", \"%s\", ...) returned %d expected %d\n",
> + string, fmt, ret, n_args);
> + goto fail;
> + }
> +
> + ret = (*fn)(check_data, string, fmt, n_args, ap);
> + if (ret)
> + goto fail;
> +
> + va_end(ap);
> +
> + return;
> +
> +fail:
> + failed_tests++;
> + va_end(ap);
> +}
> +
> +#define test_one_number(T, gen_fmt, scan_fmt, val, fn) \
> +do { \
> + const T expect_val = (T)(val); \
> + T result = ~expect_val; /* should be overwritten */ \
If I get it correctly, this is supposed to initialize the temporary
variable with a value that is different from the expected value.
It will cause test failure when it is not updated by vsscanf().
It does not work for zero value. A better solution might be to add
a constant, for example:
T result = expect_val + 3; /* do not match when not overwritten */ \
I did not use "+ 1" intentionally because it might hide some overflow
issues.
> + \
> + snprintf(test_buffer, BUF_SIZE, gen_fmt, expect_val); \
> + _test(fn, &expect_val, test_buffer, "%" scan_fmt, 1, &result); \
> +} while (0)
Otherwise, it looks good to me.
Best Regards,
Petr
On Mon 2020-11-30 14:57:59, Richard Fitzgerald wrote:
> Adds a wrapper shell script for the test_scanf module.
>
> Signed-off-by: Richard Fitzgerald <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Best Regards,
Petr
On Mon 2020-11-30 14:58:00, Richard Fitzgerald wrote:
> Adds the new scanf test to the VSPRINTF group.
>
> Signed-off-by: Richard Fitzgerald <[email protected]>
I would prefer to squash this into the 2nd patch that adds the
file. But anyway:
Reviewed-by: Petr Mladek <[email protected]>
Best Regards,
Petr
On 09/12/2020 14:15, Petr Mladek wrote:
> On Mon 2020-11-30 14:57:58, Richard Fitzgerald wrote:
>> Adds test_sscanf to test various number conversion cases, as
>> number conversion was previously broken.
>>
>> This also tests the simple_strtoxxx() functions exported from
>> vsprintf.c.
>
> It is impressive.
>
> Honestly, I do not feel to be expert on testing and mathematics.
> I am not sure how comprehensive the test is. Also I am not
> sure what experts would say about the tricks with random
> numbers.
>
> Anyway, this is much more than what I have expected. And it checks
> great number of variants and corner cases.
>
> I suggest only one small change, see below.
>
>> --- /dev/null
>> +++ b/lib/test_scanf.c
>> @@ -0,0 +1,747 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Test cases for sscanf facility.
>> + */
>> +
>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/overflow.h>
>> +#include <linux/printk.h>
>> +#include <linux/random.h>
>> +#include <linux/slab.h>
>> +#include <linux/string.h>
>> +
>> +#include "../tools/testing/selftests/kselftest_module.h"
>> +
>> +#define BUF_SIZE 1024
>> +
>> +static unsigned total_tests __initdata;
>> +static unsigned failed_tests __initdata;
>> +static char *test_buffer __initdata;
>> +static char *fmt_buffer __initdata;
>> +static struct rnd_state rnd_state __initdata;
>> +
>> +typedef int (*check_fn)(const void *check_data, const char *string,
>> + const char *fmt, int n_args, va_list ap);
>> +
>> +static void __scanf(4, 6) __init
>> +_test(check_fn fn, const void *check_data, const char *string, const char *fmt,
>> + int n_args, ...)
>> +{
>> + va_list ap, ap_copy;
>> + int ret;
>> +
>> + total_tests++;
>> +
>> + va_start(ap, n_args);
>> + va_copy(ap_copy, ap);
>> + ret = vsscanf(string, fmt, ap_copy);
>> + va_end(ap_copy);
>> +
>> + if (ret != n_args) {
>> + pr_warn("vsscanf(\"%s\", \"%s\", ...) returned %d expected %d\n",
>> + string, fmt, ret, n_args);
>> + goto fail;
>> + }
>> +
>> + ret = (*fn)(check_data, string, fmt, n_args, ap);
>> + if (ret)
>> + goto fail;
>> +
>> + va_end(ap);
>> +
>> + return;
>> +
>> +fail:
>> + failed_tests++;
>> + va_end(ap);
>> +}
>> +
>> +#define test_one_number(T, gen_fmt, scan_fmt, val, fn) \
>> +do { \
>> + const T expect_val = (T)(val); \
>> + T result = ~expect_val; /* should be overwritten */ \
>
> If I get it correctly, this is supposed to initialize the temporary
> variable with a value that is different from the expected value.
> It will cause test failure when it is not updated by vsscanf().
>
> It does not work for zero value. A better solution might be to add
That's a ~, not a -
~0 = 0xFFFFFFFF
~-1 = 0
> a constant, for example:
>
> T result = expect_val + 3; /* do not match when not overwritten */ \
>
> I did not use "+ 1" intentionally because it might hide some overflow
> issues.
>
>> + \
>> + snprintf(test_buffer, BUF_SIZE, gen_fmt, expect_val); \
>> + _test(fn, &expect_val, test_buffer, "%" scan_fmt, 1, &result); \
>> +} while (0)
>
> Otherwise, it looks good to me.
>
> Best Regards,
> Petr
>
On 12/9/20 7:22 AM, Petr Mladek wrote:
> On Mon 2020-11-30 14:58:00, Richard Fitzgerald wrote:
>> Adds the new scanf test to the VSPRINTF group.
>>
>> Signed-off-by: Richard Fitzgerald <[email protected]>
>
> I would prefer to squash this into the 2nd patch that adds the
> file. But anyway:
>
> Reviewed-by: Petr Mladek <[email protected]>
>
Agree with Petr. Squashing this with patch 2 is preferred.
thanks,
-- Shuah