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linux/lib/test-string_helpers.c
Rasmus Villemoes 41416f2330 lib/string_helpers.c: change semantics of string_escape_mem 
The current semantics of string_escape_mem are inadequate for one of its
current users, vsnprintf().  If that is to honour its contract, it must
know how much space would be needed for the entire escaped buffer, and
string_escape_mem provides no way of obtaining that (short of allocating a
large enough buffer (~4 times input string) to let it play with, and
that's definitely a big no-no inside vsnprintf).

So change the semantics for string_escape_mem to be more snprintf-like:
Return the size of the output that would be generated if the destination
buffer was big enough, but of course still only write to the part of dst
it is allowed to, and (contrary to snprintf) don't do '\0'-termination.
It is then up to the caller to detect whether output was truncated and to
append a '\0' if desired.  Also, we must output partial escape sequences,
otherwise a call such as snprintf(buf, 3, "%1pE", "\123") would cause
printf to write a \0 to buf[2] but leaving buf[0] and buf[1] with whatever
they previously contained.

This also fixes a bug in the escaped_string() helper function, which used
to unconditionally pass a length of "end-buf" to string_escape_mem();
since the latter doesn't check osz for being insanely large, it would
happily write to dst.  For example, kasprintf(GFP_KERNEL, "something and
then %pE", ...); is an easy way to trigger an oops.

In test-string_helpers.c, the -ENOMEM test is replaced with testing for
getting the expected return value even if the buffer is too small.  We
also ensure that nothing is written (by relying on a NULL pointer deref)
if the output size is 0 by passing NULL - this has to work for
kasprintf("%pE") to work.

In net/sunrpc/cache.c, I think qword_add still has the same semantics.
Someone should definitely double-check this.

In fs/proc/array.c, I made the minimum possible change, but longer-term it
should stop poking around in seq_file internals.

[andriy.shevchenko@linux.intel.com: simplify qword_add]
[andriy.shevchenko@linux.intel.com: add missed curly braces]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 16:35:24 -07:00

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/*
* Test cases for lib/string_helpers.c module.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/string.h>
#include <linux/string_helpers.h>
static __init bool test_string_check_buf(const char *name, unsigned int flags,
char *in, size_t p,
char *out_real, size_t q_real,
char *out_test, size_t q_test)
{
if (q_real == q_test && !memcmp(out_test, out_real, q_test))
return true;
pr_warn("Test '%s' failed: flags = %u\n", name, flags);
print_hex_dump(KERN_WARNING, "Input: ", DUMP_PREFIX_NONE, 16, 1,
in, p, true);
print_hex_dump(KERN_WARNING, "Expected: ", DUMP_PREFIX_NONE, 16, 1,
out_test, q_test, true);
print_hex_dump(KERN_WARNING, "Got: ", DUMP_PREFIX_NONE, 16, 1,
out_real, q_real, true);
return false;
}
struct test_string {
const char *in;
const char *out;
unsigned int flags;
};
static const struct test_string strings[] __initconst = {
{
.in = "\\f\\ \\n\\r\\t\\v",
.out = "\f\\ \n\r\t\v",
.flags = UNESCAPE_SPACE,
},
{
.in = "\\40\\1\\387\\0064\\05\\040\\8a\\110\\777",
.out = " \001\00387\0064\005 \\8aH?7",
.flags = UNESCAPE_OCTAL,
},
{
.in = "\\xv\\xa\\x2c\\xD\\x6f2",
.out = "\\xv\n,\ro2",
.flags = UNESCAPE_HEX,
},
{
.in = "\\h\\\\\\\"\\a\\e\\",
.out = "\\h\\\"\a\e\\",
.flags = UNESCAPE_SPECIAL,
},
};
static void __init test_string_unescape(const char *name, unsigned int flags,
bool inplace)
{
int q_real = 256;
char *in = kmalloc(q_real, GFP_KERNEL);
char *out_test = kmalloc(q_real, GFP_KERNEL);
char *out_real = kmalloc(q_real, GFP_KERNEL);
int i, p = 0, q_test = 0;
if (!in || !out_test || !out_real)
goto out;
for (i = 0; i < ARRAY_SIZE(strings); i++) {
const char *s = strings[i].in;
int len = strlen(strings[i].in);
/* Copy string to in buffer */
memcpy(&in[p], s, len);
p += len;
/* Copy expected result for given flags */
if (flags & strings[i].flags) {
s = strings[i].out;
len = strlen(strings[i].out);
}
memcpy(&out_test[q_test], s, len);
q_test += len;
}
in[p++] = '\0';
/* Call string_unescape and compare result */
if (inplace) {
memcpy(out_real, in, p);
if (flags == UNESCAPE_ANY)
q_real = string_unescape_any_inplace(out_real);
else
q_real = string_unescape_inplace(out_real, flags);
} else if (flags == UNESCAPE_ANY) {
q_real = string_unescape_any(in, out_real, q_real);
} else {
q_real = string_unescape(in, out_real, q_real, flags);
}
test_string_check_buf(name, flags, in, p - 1, out_real, q_real,
out_test, q_test);
out:
kfree(out_real);
kfree(out_test);
kfree(in);
}
struct test_string_1 {
const char *out;
unsigned int flags;
};
#define TEST_STRING_2_MAX_S1 32
struct test_string_2 {
const char *in;
struct test_string_1 s1[TEST_STRING_2_MAX_S1];
};
#define TEST_STRING_2_DICT_0 NULL
static const struct test_string_2 escape0[] __initconst = {{
.in = "\f\\ \n\r\t\v",
.s1 = {{
.out = "\\f\\ \\n\\r\\t\\v",
.flags = ESCAPE_SPACE,
},{
.out = "\\f\\134\\040\\n\\r\\t\\v",
.flags = ESCAPE_SPACE | ESCAPE_OCTAL,
},{
.out = "\\f\\x5c\\x20\\n\\r\\t\\v",
.flags = ESCAPE_SPACE | ESCAPE_HEX,
},{
/* terminator */
}},
},{
.in = "\\h\\\"\a\e\\",
.s1 = {{
.out = "\\\\h\\\\\"\\a\\e\\\\",
.flags = ESCAPE_SPECIAL,
},{
.out = "\\\\\\150\\\\\\042\\a\\e\\\\",
.flags = ESCAPE_SPECIAL | ESCAPE_OCTAL,
},{
.out = "\\\\\\x68\\\\\\x22\\a\\e\\\\",
.flags = ESCAPE_SPECIAL | ESCAPE_HEX,
},{
/* terminator */
}},
},{
.in = "\eb \\C\007\"\x90\r]",
.s1 = {{
.out = "\eb \\C\007\"\x90\\r]",
.flags = ESCAPE_SPACE,
},{
.out = "\\eb \\\\C\\a\"\x90\r]",
.flags = ESCAPE_SPECIAL,
},{
.out = "\\eb \\\\C\\a\"\x90\\r]",
.flags = ESCAPE_SPACE | ESCAPE_SPECIAL,
},{
.out = "\\033\\142\\040\\134\\103\\007\\042\\220\\015\\135",
.flags = ESCAPE_OCTAL,
},{
.out = "\\033\\142\\040\\134\\103\\007\\042\\220\\r\\135",
.flags = ESCAPE_SPACE | ESCAPE_OCTAL,
},{
.out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\015\\135",
.flags = ESCAPE_SPECIAL | ESCAPE_OCTAL,
},{
.out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\r\\135",
.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_OCTAL,
},{
.out = "\eb \\C\007\"\x90\r]",
.flags = ESCAPE_NP,
},{
.out = "\eb \\C\007\"\x90\\r]",
.flags = ESCAPE_SPACE | ESCAPE_NP,
},{
.out = "\\eb \\C\\a\"\x90\r]",
.flags = ESCAPE_SPECIAL | ESCAPE_NP,
},{
.out = "\\eb \\C\\a\"\x90\\r]",
.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_NP,
},{
.out = "\\033b \\C\\007\"\\220\\015]",
.flags = ESCAPE_OCTAL | ESCAPE_NP,
},{
.out = "\\033b \\C\\007\"\\220\\r]",
.flags = ESCAPE_SPACE | ESCAPE_OCTAL | ESCAPE_NP,
},{
.out = "\\eb \\C\\a\"\\220\\r]",
.flags = ESCAPE_SPECIAL | ESCAPE_SPACE | ESCAPE_OCTAL |
ESCAPE_NP,
},{
.out = "\\x1bb \\C\\x07\"\\x90\\x0d]",
.flags = ESCAPE_NP | ESCAPE_HEX,
},{
/* terminator */
}},
},{
/* terminator */
}};
#define TEST_STRING_2_DICT_1 "b\\ \t\r"
static const struct test_string_2 escape1[] __initconst = {{
.in = "\f\\ \n\r\t\v",
.s1 = {{
.out = "\f\\134\\040\n\\015\\011\v",
.flags = ESCAPE_OCTAL,
},{
.out = "\f\\x5c\\x20\n\\x0d\\x09\v",
.flags = ESCAPE_HEX,
},{
/* terminator */
}},
},{
.in = "\\h\\\"\a\e\\",
.s1 = {{
.out = "\\134h\\134\"\a\e\\134",
.flags = ESCAPE_OCTAL,
},{
/* terminator */
}},
},{
.in = "\eb \\C\007\"\x90\r]",
.s1 = {{
.out = "\e\\142\\040\\134C\007\"\x90\\015]",
.flags = ESCAPE_OCTAL,
},{
/* terminator */
}},
},{
/* terminator */
}};
static __init const char *test_string_find_match(const struct test_string_2 *s2,
unsigned int flags)
{
const struct test_string_1 *s1 = s2->s1;
unsigned int i;
if (!flags)
return s2->in;
/* Test cases are NULL-aware */
flags &= ~ESCAPE_NULL;
/* ESCAPE_OCTAL has a higher priority */
if (flags & ESCAPE_OCTAL)
flags &= ~ESCAPE_HEX;
for (i = 0; i < TEST_STRING_2_MAX_S1 && s1->out; i++, s1++)
if (s1->flags == flags)
return s1->out;
return NULL;
}
static __init void
test_string_escape_overflow(const char *in, int p, unsigned int flags, const char *esc,
int q_test, const char *name)
{
int q_real;
q_real = string_escape_mem(in, p, NULL, 0, flags, esc);
if (q_real != q_test)
pr_warn("Test '%s' failed: flags = %u, osz = 0, expected %d, got %d\n",
name, flags, q_test, q_real);
}
static __init void test_string_escape(const char *name,
const struct test_string_2 *s2,
unsigned int flags, const char *esc)
{
size_t out_size = 512;
char *out_test = kmalloc(out_size, GFP_KERNEL);
char *out_real = kmalloc(out_size, GFP_KERNEL);
char *in = kmalloc(256, GFP_KERNEL);
int p = 0, q_test = 0;
int q_real;
if (!out_test || !out_real || !in)
goto out;
for (; s2->in; s2++) {
const char *out;
int len;
/* NULL injection */
if (flags & ESCAPE_NULL) {
in[p++] = '\0';
out_test[q_test++] = '\\';
out_test[q_test++] = '0';
}
/* Don't try strings that have no output */
out = test_string_find_match(s2, flags);
if (!out)
continue;
/* Copy string to in buffer */
len = strlen(s2->in);
memcpy(&in[p], s2->in, len);
p += len;
/* Copy expected result for given flags */
len = strlen(out);
memcpy(&out_test[q_test], out, len);
q_test += len;
}
q_real = string_escape_mem(in, p, out_real, out_size, flags, esc);
test_string_check_buf(name, flags, in, p, out_real, q_real, out_test,
q_test);
test_string_escape_overflow(in, p, flags, esc, q_test, name);
out:
kfree(in);
kfree(out_real);
kfree(out_test);
}
static int __init test_string_helpers_init(void)
{
unsigned int i;
pr_info("Running tests...\n");
for (i = 0; i < UNESCAPE_ANY + 1; i++)
test_string_unescape("unescape", i, false);
test_string_unescape("unescape inplace",
get_random_int() % (UNESCAPE_ANY + 1), true);
/* Without dictionary */
for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
test_string_escape("escape 0", escape0, i, TEST_STRING_2_DICT_0);
/* With dictionary */
for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
test_string_escape("escape 1", escape1, i, TEST_STRING_2_DICT_1);
return -EINVAL;
}
module_init(test_string_helpers_init);
MODULE_LICENSE("Dual BSD/GPL");
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