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	Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value,
simply use the get_random_{u8,u16}() functions, which are faster than
wasting the additional bytes from a 32-bit value. This was done
mechanically with this coccinelle script:
@@
expression E;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
typedef __be16;
typedef __le16;
typedef u8;
@@
(
- (get_random_u32() & 0xffff)
+ get_random_u16()
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- (get_random_u32() & 0xff)
+ get_random_u8()
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- (get_random_u32() % 65536)
+ get_random_u16()
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- (get_random_u32() % 256)
+ get_random_u8()
|
- (get_random_u32() >> 16)
+ get_random_u16()
|
- (get_random_u32() >> 24)
+ get_random_u8()
|
- (u16)get_random_u32()
+ get_random_u16()
|
- (u8)get_random_u32()
+ get_random_u8()
|
- (__be16)get_random_u32()
+ (__be16)get_random_u16()
|
- (__le16)get_random_u32()
+ (__le16)get_random_u16()
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- prandom_u32_max(65536)
+ get_random_u16()
|
- prandom_u32_max(256)
+ get_random_u8()
|
- E->inet_id = get_random_u32()
+ E->inet_id = get_random_u16()
)
@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
identifier v;
@@
- u16 v = get_random_u32();
+ u16 v = get_random_u16();
@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u8;
identifier v;
@@
- u8 v = get_random_u32();
+ u8 v = get_random_u8();
@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
u16 v;
@@
-  v = get_random_u32();
+  v = get_random_u16();
@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u8;
u8 v;
@@
-  v = get_random_u32();
+  v = get_random_u8();
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
        ((T)get_random_u32()@p & (LITERAL))
// Examine limits
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value < 256:
        coccinelle.RESULT = cocci.make_ident("get_random_u8")
elif value < 65536:
        coccinelle.RESULT = cocci.make_ident("get_random_u16")
else:
        print("Skipping large mask of %s" % (literal))
        cocci.include_match(False)
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
identifier add_one.RESULT;
identifier FUNC;
@@
-       (FUNC()@p & (LITERAL))
+       (RESULT() & LITERAL)
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
		
	
			
		
			
				
	
	
		
			156 lines
		
	
	
	
		
			4.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			156 lines
		
	
	
	
		
			4.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0+
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/*
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 * Test cases for API provided by cmdline.c
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 */
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#include <kunit/test.h>
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#include <linux/kernel.h>
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#include <linux/random.h>
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#include <linux/string.h>
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static const char *cmdline_test_strings[] = {
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	"\"\"", ""  , "=" , "\"-", ","    , "-,"   , ",-"   , "-" ,
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	"+,"  , "--", ",,", "''" , "\"\",", "\",\"", "-\"\"", "\"",
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};
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static const int cmdline_test_values[] = {
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	1, 1, 1, 1, 2, 3, 2, 3,
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	1, 3, 2, 1, 1, 1, 3, 1,
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};
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static_assert(ARRAY_SIZE(cmdline_test_strings) == ARRAY_SIZE(cmdline_test_values));
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static const char *cmdline_test_range_strings[] = {
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	"-7" , "--7"  , "-1-2"    , "7--9",
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	"7-" , "-7--9", "7-9,"    , "9-7" ,
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	"5-a", "a-5"  , "5-8"     , ",8-5",
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	"+,1", "-,4"  , "-3,0-1,6", "4,-" ,
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	" +2", " -9"  , "0-1,-3,6", "- 9" ,
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};
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static const int cmdline_test_range_values[][16] = {
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	{ 1, -7, }, { 0, -0, }, { 4, -1, 0, +1, 2, }, { 0, 7, },
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	{ 0, +7, }, { 0, -7, }, { 3, +7, 8, +9, 0, }, { 0, 9, },
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	{ 0, +5, }, { 0, -0, }, { 4, +5, 6, +7, 8, }, { 0, 0, },
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	{ 0, +0, }, { 0, -0, }, { 4, -3, 0, +1, 6, }, { 1, 4, },
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	{ 0, +0, }, { 0, -0, }, { 4, +0, 1, -3, 6, }, { 0, 0, },
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};
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static_assert(ARRAY_SIZE(cmdline_test_range_strings) == ARRAY_SIZE(cmdline_test_range_values));
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static void cmdline_do_one_test(struct kunit *test, const char *in, int rc, int offset)
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{
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	const char *fmt = "Pattern: %s";
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	const char *out = in;
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	int dummy;
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	int ret;
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	ret = get_option((char **)&out, &dummy);
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	KUNIT_EXPECT_EQ_MSG(test, ret, rc, fmt, in);
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	KUNIT_EXPECT_PTR_EQ_MSG(test, out, in + offset, fmt, in);
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}
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static void cmdline_test_noint(struct kunit *test)
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{
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	unsigned int i = 0;
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	do {
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		const char *str = cmdline_test_strings[i];
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		int rc = 0;
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		int offset;
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		/* Only first and leading '-' will advance the pointer */
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		offset = !!(*str == '-');
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		cmdline_do_one_test(test, str, rc, offset);
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	} while (++i < ARRAY_SIZE(cmdline_test_strings));
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}
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static void cmdline_test_lead_int(struct kunit *test)
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{
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	unsigned int i = 0;
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	char in[32];
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	do {
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		const char *str = cmdline_test_strings[i];
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		int rc = cmdline_test_values[i];
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		int offset;
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		sprintf(in, "%u%s", get_random_u8(), str);
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		/* Only first '-' after the number will advance the pointer */
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		offset = strlen(in) - strlen(str) + !!(rc == 2);
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		cmdline_do_one_test(test, in, rc, offset);
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	} while (++i < ARRAY_SIZE(cmdline_test_strings));
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}
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static void cmdline_test_tail_int(struct kunit *test)
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{
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	unsigned int i = 0;
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	char in[32];
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	do {
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		const char *str = cmdline_test_strings[i];
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		/* When "" or "-" the result will be valid integer */
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		int rc = strcmp(str, "") ? (strcmp(str, "-") ? 0 : 1) : 1;
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		int offset;
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		sprintf(in, "%s%u", str, get_random_u8());
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		/*
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		 * Only first and leading '-' not followed by integer
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		 * will advance the pointer.
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		 */
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		offset = rc ? strlen(in) : !!(*str == '-');
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		cmdline_do_one_test(test, in, rc, offset);
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	} while (++i < ARRAY_SIZE(cmdline_test_strings));
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}
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static void cmdline_do_one_range_test(struct kunit *test, const char *in,
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				      unsigned int n, const int *e)
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{
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	unsigned int i;
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	int r[16];
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	int *p;
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	memset(r, 0, sizeof(r));
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	get_options(in, ARRAY_SIZE(r), r);
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	KUNIT_EXPECT_EQ_MSG(test, r[0], e[0], "in test %u (parsed) expected %d numbers, got %d",
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			    n, e[0], r[0]);
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	for (i = 1; i < ARRAY_SIZE(r); i++)
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		KUNIT_EXPECT_EQ_MSG(test, r[i], e[i], "in test %u at %u", n, i);
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	memset(r, 0, sizeof(r));
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	get_options(in, 0, r);
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	KUNIT_EXPECT_EQ_MSG(test, r[0], e[0], "in test %u (validated) expected %d numbers, got %d",
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			    n, e[0], r[0]);
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	p = memchr_inv(&r[1], 0, sizeof(r) - sizeof(r[0]));
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	KUNIT_EXPECT_PTR_EQ_MSG(test, p, NULL, "in test %u at %u out of bound", n, p - r);
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}
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static void cmdline_test_range(struct kunit *test)
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{
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	unsigned int i = 0;
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	do {
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		const char *str = cmdline_test_range_strings[i];
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		const int *e = cmdline_test_range_values[i];
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		cmdline_do_one_range_test(test, str, i, e);
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	} while (++i < ARRAY_SIZE(cmdline_test_range_strings));
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}
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static struct kunit_case cmdline_test_cases[] = {
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	KUNIT_CASE(cmdline_test_noint),
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	KUNIT_CASE(cmdline_test_lead_int),
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	KUNIT_CASE(cmdline_test_tail_int),
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	KUNIT_CASE(cmdline_test_range),
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	{}
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};
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static struct kunit_suite cmdline_test_suite = {
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	.name = "cmdline",
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	.test_cases = cmdline_test_cases,
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};
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kunit_test_suite(cmdline_test_suite);
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MODULE_LICENSE("GPL");
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