Files
redis/src/util.h
ranshid eacca729a5 Avoid using unsafe C functions (#10932)
replace use of:
sprintf --> snprintf
strcpy/strncpy  --> redis_strlcpy
strcat/strncat  --> redis_strlcat

**why are we making this change?**
Much of the code uses some unsafe variants or deprecated buffer handling
functions.
While most cases are probably not presenting any issue on the known path
programming errors and unterminated strings might lead to potential
buffer overflows which are not covered by tests.

**As part of this PR we change**
1. added implementation for redis_strlcpy and redis_strlcat based on the strl implementation: https://linux.die.net/man/3/strl
2. change all occurrences of use of sprintf with use of snprintf
3. change occurrences of use of  strcpy/strncpy with redis_strlcpy
4. change occurrences of use of strcat/strncat with redis_strlcat
5. change the behavior of ll2string/ull2string/ld2string so that it will always place null
  termination ('\0') on the output buffer in the first index. this was done in order to make
  the use of these functions more safe in cases were the user will not check the output
  returned by them (for example in rdbRemoveTempFile)
6. we added a compiler directive to issue a deprecation error in case a use of
  sprintf/strcpy/strcat is found during compilation which will result in error during compile time.
  However keep in mind that since the deprecation attribute is not supported on all compilers,
  this is expected to fail during push workflows.


**NOTE:** while this is only an initial milestone. We might also consider
using the *_s implementation provided by the C11 Extensions (however not
yet widly supported). I would also suggest to start
looking at static code analyzers to track unsafe use cases.
For example LLVM clang checker supports security.insecureAPI.DeprecatedOrUnsafeBufferHandling
which can help locate unsafe function usage.
https://clang.llvm.org/docs/analyzer/checkers.html#security-insecureapi-deprecatedorunsafebufferhandling-c
The main reason not to onboard it at this stage is that the alternative
excepted by clang is to use the C11 extensions which are not always
supported by stdlib.
2022-07-18 10:56:26 +03:00

98 lines
4.1 KiB
C

/*
* Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __REDIS_UTIL_H
#define __REDIS_UTIL_H
#include <stdint.h>
#include "sds.h"
/* The maximum number of characters needed to represent a long double
* as a string (long double has a huge range of some 4952 chars, see LDBL_MAX).
* This should be the size of the buffer given to ld2string */
#define MAX_LONG_DOUBLE_CHARS 5*1024
/* The maximum number of characters needed to represent a double
* as a string (double has a huge range of some 328 chars, see DBL_MAX).
* This should be the size of the buffer for sprintf with %f */
#define MAX_DOUBLE_CHARS 400
/* The maximum number of characters needed to for d2string call.
* Since it uses %g and not %f, some 40 chars should be enough. */
#define MAX_D2STRING_CHARS 128
/* Bytes needed for long -> str + '\0' */
#define LONG_STR_SIZE 21
/* long double to string conversion options */
typedef enum {
LD_STR_AUTO, /* %.17Lg */
LD_STR_HUMAN, /* %.17Lf + Trimming of trailing zeros */
LD_STR_HEX /* %La */
} ld2string_mode;
int stringmatchlen(const char *p, int plen, const char *s, int slen, int nocase);
int stringmatch(const char *p, const char *s, int nocase);
int stringmatchlen_fuzz_test(void);
unsigned long long memtoull(const char *p, int *err);
const char *mempbrk(const char *s, size_t len, const char *chars, size_t charslen);
char *memmapchars(char *s, size_t len, const char *from, const char *to, size_t setlen);
uint32_t digits10(uint64_t v);
uint32_t sdigits10(int64_t v);
int ll2string(char *s, size_t len, long long value);
int ull2string(char *s, size_t len, unsigned long long value);
int string2ll(const char *s, size_t slen, long long *value);
int string2ull(const char *s, unsigned long long *value);
int string2l(const char *s, size_t slen, long *value);
int string2ld(const char *s, size_t slen, long double *dp);
int string2d(const char *s, size_t slen, double *dp);
int trimDoubleString(char *buf, size_t len);
int d2string(char *buf, size_t len, double value);
int ld2string(char *buf, size_t len, long double value, ld2string_mode mode);
int double2ll(double d, long long *out);
int yesnotoi(char *s);
sds getAbsolutePath(char *filename);
long getTimeZone(void);
int pathIsBaseName(char *path);
int dirCreateIfMissing(char *dname);
int dirExists(char *dname);
int dirRemove(char *dname);
int fileExist(char *filename);
sds makePath(char *path, char *filename);
int fsyncFileDir(const char *filename);
size_t redis_strlcpy(char *dst, const char *src, size_t dsize);
size_t redis_strlcat(char *dst, const char *src, size_t dsize);
#ifdef REDIS_TEST
int utilTest(int argc, char **argv, int flags);
#endif
#endif