| From 08f5e0df46ce1ad617bcde1fd5542545397630b9 Mon Sep 17 00:00:00 2001 |
| From: Hans Dedecker <dedeckeh@gmail.com> |
| Date: Sat, 24 Oct 2020 21:13:30 +0200 |
| Subject: Revert "Disallow use of DES encryption functions in new programs." |
| |
| This reverts commit b10a0accee709a5efff2fadf0b0bbb79ff0ad759. |
| |
| ppp still uses the encrypt functions from the libc while musl libc also |
| provides them. |
| --- |
| conform/data/stdlib.h-data | 3 + |
| conform/data/unistd.h-data | 6 ++ |
| crypt/cert.c | 26 ----- |
| crypt/crypt-entry.c | 15 ++- |
| crypt/crypt.h | 16 +++ |
| crypt/crypt_util.c | 9 -- |
| manual/conf.texi | 2 - |
| manual/crypt.texi | 204 +++++++++++++++++++++++++++++++++++++ |
| manual/string.texi | 82 +++++++-------- |
| posix/unistd.h | 17 +++- |
| stdlib/stdlib.h | 6 ++ |
| sunrpc/des_crypt.c | 7 +- |
| sunrpc/des_soft.c | 2 +- |
| 13 files changed, 305 insertions(+), 90 deletions(-) |
| |
| --- a/conform/data/stdlib.h-data |
| +++ b/conform/data/stdlib.h-data |
| @@ -149,6 +149,9 @@ function {unsigned short int*} seed48 (u |
| #if !defined ISO && !defined ISO99 && !defined ISO11 && !defined POSIX && !defined XPG4 && !defined XPG42 && !defined UNIX98 |
| function int setenv (const char*, const char*, int) |
| #endif |
| +#if !defined ISO && !defined ISO99 && !defined ISO11 && !defined POSIX && !defined POSIX2008 |
| +function void setkey (const char*) |
| +#endif |
| #if !defined ISO && !defined ISO99 && !defined ISO11 && !defined XPG4 && !defined POSIX && !defined POSIX2008 |
| function {char*} setstate (char*) |
| #endif |
| --- a/conform/data/unistd.h-data |
| +++ b/conform/data/unistd.h-data |
| @@ -437,6 +437,9 @@ function int chroot (const char*) |
| function int chown (const char*, uid_t, gid_t) |
| function int close (int) |
| function size_t confstr (int, char*, size_t) |
| +#if !defined POSIX && !defined POSIX2008 |
| +function {char*} crypt (const char*, const char*) |
| +#endif |
| #if defined XPG4 || defined XPG42 || defined UNIX98 |
| function {char*} ctermid (char*) |
| function {char*} cuserid (char*) |
| @@ -446,6 +449,9 @@ allow cuserid |
| #endif |
| function int dup (int) |
| function int dup2 (int, int) |
| +#if !defined POSIX && !defined POSIX2008 |
| +function void encrypt (char[64], int) |
| +#endif |
| function int execl (const char*, const char*, ...) |
| function int execle (const char*, const char*, ...) |
| function int execlp (const char*, const char*, ...) |
| --- a/crypt/cert.c |
| +++ b/crypt/cert.c |
| @@ -10,22 +10,6 @@ |
| #include <stdlib.h> |
| #include "crypt.h" |
| |
| -/* This file tests the deprecated setkey/encrypt interface. */ |
| -#include <shlib-compat.h> |
| -#if TEST_COMPAT (libcrypt, GLIBC_2_0, GLIBC_2_28) |
| - |
| -#define libcrypt_version_reference(symbol, version) \ |
| - _libcrypt_version_reference (symbol, VERSION_libcrypt_##version) |
| -#define _libcrypt_version_reference(symbol, version) \ |
| - __libcrypt_version_reference (symbol, version) |
| -#define __libcrypt_version_reference(symbol, version) \ |
| - __asm__ (".symver " #symbol ", " #symbol "@" #version) |
| - |
| -extern void setkey (const char *); |
| -extern void encrypt (const char *, int); |
| -libcrypt_version_reference (setkey, GLIBC_2_0); |
| -libcrypt_version_reference (encrypt, GLIBC_2_0); |
| - |
| int totfails = 0; |
| |
| int main (int argc, char *argv[]); |
| @@ -123,13 +107,3 @@ put8 (char *cp) |
| printf("%02x", t); |
| } |
| } |
| - |
| -#else /* encrypt and setkey are not available. */ |
| - |
| -int |
| -main (void) |
| -{ |
| - return 77; /* UNSUPPORTED */ |
| -} |
| - |
| -#endif |
| --- a/crypt/crypt-entry.c |
| +++ b/crypt/crypt-entry.c |
| @@ -35,7 +35,6 @@ |
| #endif |
| |
| #include "crypt-private.h" |
| -#include <shlib-compat.h> |
| |
| /* Prototypes for local functions. */ |
| #ifndef __GNU_LIBRARY__ |
| @@ -177,7 +176,17 @@ crypt (const char *key, const char *salt |
| return __crypt_r (key, salt, &_ufc_foobar); |
| } |
| |
| -#if SHLIB_COMPAT (libcrypt, GLIBC_2_0, GLIBC_2_28) |
| + |
| +/* |
| + * To make fcrypt users happy. |
| + * They don't need to call init_des. |
| + */ |
| +#ifdef _LIBC |
| weak_alias (crypt, fcrypt) |
| -compat_symbol (libcrypt, fcrypt, fcrypt, GLIBC_2_0); |
| +#else |
| +char * |
| +__fcrypt (const char *key, const char *salt) |
| +{ |
| + return crypt (key, salt); |
| +} |
| #endif |
| --- a/crypt/crypt.h |
| +++ b/crypt/crypt.h |
| @@ -36,6 +36,14 @@ __BEGIN_DECLS |
| extern char *crypt (const char *__phrase, const char *__salt) |
| __THROW __nonnull ((1, 2)); |
| |
| +/* Setup DES tables according KEY. */ |
| +extern void setkey (const char *__key) __THROW __nonnull ((1)); |
| + |
| +/* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt |
| + block in place. */ |
| +extern void encrypt (char *__glibc_block, int __edflag) |
| + __THROW __nonnull ((1)); |
| + |
| #ifdef __USE_GNU |
| |
| /* This structure provides scratch and output buffers for 'crypt_r'. |
| @@ -63,6 +71,14 @@ struct crypt_data |
| extern char *crypt_r (const char *__phrase, const char *__salt, |
| struct crypt_data * __restrict __data) |
| __THROW __nonnull ((1, 2, 3)); |
| + |
| +extern void setkey_r (const char *__key, |
| + struct crypt_data * __restrict __data) |
| + __THROW __nonnull ((1, 2)); |
| + |
| +extern void encrypt_r (char *__glibc_block, int __edflag, |
| + struct crypt_data * __restrict __data) |
| + __THROW __nonnull ((1, 3)); |
| #endif |
| |
| __END_DECLS |
| --- a/crypt/crypt_util.c |
| +++ b/crypt/crypt_util.c |
| @@ -34,7 +34,6 @@ |
| #endif |
| |
| #include "crypt-private.h" |
| -#include <shlib-compat.h> |
| |
| /* Prototypes for local functions. */ |
| #ifndef __GNU_LIBRARY__ |
| @@ -151,7 +150,6 @@ static const int sbox[8][4][16]= { |
| } |
| }; |
| |
| -#if SHLIB_COMPAT (libcrypt, GLIBC_2_0, GLIBC_2_28) |
| /* |
| * This is the initial |
| * permutation matrix |
| @@ -162,7 +160,6 @@ static const int initial_perm[64] = { |
| 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, |
| 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 |
| }; |
| -#endif |
| |
| /* |
| * This is the final |
| @@ -788,7 +785,6 @@ _ufc_output_conversion_r (ufc_long v1, u |
| __data->crypt_3_buf[13] = 0; |
| } |
| |
| -#if SHLIB_COMPAT (libcrypt, GLIBC_2_0, GLIBC_2_28) |
| |
| /* |
| * UNIX encrypt function. Takes a bitvector |
| @@ -889,14 +885,12 @@ __encrypt_r (char *__block, int __edflag |
| } |
| } |
| weak_alias (__encrypt_r, encrypt_r) |
| -compat_symbol (libcrypt, encrypt_r, encrypt_r, GLIBC_2_0); |
| |
| void |
| encrypt (char *__block, int __edflag) |
| { |
| __encrypt_r(__block, __edflag, &_ufc_foobar); |
| } |
| -compat_symbol (libcrypt, encrypt, encrypt, GLIBC_2_0); |
| |
| |
| /* |
| @@ -921,15 +915,12 @@ __setkey_r (const char *__key, struct cr |
| _ufc_mk_keytab_r((char *) ktab, __data); |
| } |
| weak_alias (__setkey_r, setkey_r) |
| -compat_symbol (libcrypt, setkey_r, setkey_r, GLIBC_2_0); |
| |
| void |
| setkey (const char *__key) |
| { |
| __setkey_r(__key, &_ufc_foobar); |
| } |
| -compat_symbol (libcrypt, setkey, setkey, GLIBC_2_0); |
| -#endif /* SHLIB_COMPAT (libcrypt, GLIBC_2_0, GLIBC_2_28) */ |
| |
| void |
| __b64_from_24bit (char **cp, int *buflen, |
| --- a/manual/conf.texi |
| +++ b/manual/conf.texi |
| @@ -780,8 +780,6 @@ Inquire about the parameter correspondin |
| @item _SC_XOPEN_CRYPT |
| @standards{X/Open, unistd.h} |
| Inquire about the parameter corresponding to @code{_XOPEN_CRYPT}. |
| -@Theglibc no longer implements the @code{_XOPEN_CRYPT} extensions, |
| -so @samp{sysconf (_SC_XOPEN_CRYPT)} always returns @code{-1}. |
| |
| @item _SC_XOPEN_ENH_I18N |
| @standards{X/Open, unistd.h} |
| --- a/manual/crypt.texi |
| +++ b/manual/crypt.texi |
| @@ -16,8 +16,19 @@ subject to them, even if you do not use |
| yourself. The restrictions vary from place to place and are changed |
| often, so we cannot give any more specific advice than this warning. |
| |
| +@vindex AUTH_DES |
| +@cindex FIPS 140-2 |
| +It also provides support for Secure RPC, and some library functions that |
| +can be used to perform normal DES encryption. The @code{AUTH_DES} |
| +authentication flavor in Secure RPC, as provided by @theglibc{}, |
| +uses DES and does not comply with FIPS 140-2 nor does any other use of DES |
| +within @theglibc{}. It is recommended that Secure RPC should not be used |
| +for systems that need to comply with FIPS 140-2 since all flavors of |
| +encrypted authentication use normal DES. |
| + |
| @menu |
| * Passphrase Storage:: One-way hashing for passphrases. |
| +* crypt:: A one-way function for passwords. |
| * Unpredictable Bytes:: Randomness for cryptographic purposes. |
| @end menu |
| |
| @@ -190,6 +201,199 @@ unpredictable as possible; @pxref{Unpred |
| @include genpass.c.texi |
| @end smallexample |
| |
| +@node DES Encryption |
| +@section DES Encryption |
| + |
| +@cindex FIPS 46-3 |
| +The Data Encryption Standard is described in the US Government Federal |
| +Information Processing Standards (FIPS) 46-3 published by the National |
| +Institute of Standards and Technology. The DES has been very thoroughly |
| +analyzed since it was developed in the late 1970s, and no new |
| +significant flaws have been found. |
| + |
| +However, the DES uses only a 56-bit key (plus 8 parity bits), and a |
| +machine has been built in 1998 which can search through all possible |
| +keys in about 6 days, which cost about US$200000; faster searches would |
| +be possible with more money. This makes simple DES insecure for most |
| +purposes, and NIST no longer permits new US government systems |
| +to use simple DES. |
| + |
| +For serious encryption functionality, it is recommended that one of the |
| +many free encryption libraries be used instead of these routines. |
| + |
| +The DES is a reversible operation which takes a 64-bit block and a |
| +64-bit key, and produces another 64-bit block. Usually the bits are |
| +numbered so that the most-significant bit, the first bit, of each block |
| +is numbered 1. |
| + |
| +Under that numbering, every 8th bit of the key (the 8th, 16th, and so |
| +on) is not used by the encryption algorithm itself. But the key must |
| +have odd parity; that is, out of bits 1 through 8, and 9 through 16, and |
| +so on, there must be an odd number of `1' bits, and this completely |
| +specifies the unused bits. |
| + |
| +@deftypefun void setkey (const char *@var{key}) |
| +@standards{BSD, crypt.h} |
| +@standards{SVID, crypt.h} |
| +@safety{@prelim{}@mtunsafe{@mtasurace{:crypt}}@asunsafe{@asucorrupt{} @asulock{}}@acunsafe{@aculock{}}} |
| +@c The static buffer stores the key, making it fundamentally |
| +@c thread-unsafe. The locking issues are only in the initialization |
| +@c path; cancelling the initialization will leave the lock held, it |
| +@c would otherwise repeat the initialization on the next call. |
| + |
| +The @code{setkey} function sets an internal data structure to be an |
| +expanded form of @var{key}. @var{key} is specified as an array of 64 |
| +bits each stored in a @code{char}, the first bit is @code{key[0]} and |
| +the 64th bit is @code{key[63]}. The @var{key} should have the correct |
| +parity. |
| +@end deftypefun |
| + |
| +@deftypefun void encrypt (char *@var{block}, int @var{edflag}) |
| +@standards{BSD, crypt.h} |
| +@standards{SVID, crypt.h} |
| +@safety{@prelim{}@mtunsafe{@mtasurace{:crypt}}@asunsafe{@asucorrupt{} @asulock{}}@acunsafe{@aculock{}}} |
| +@c Same issues as setkey. |
| + |
| +The @code{encrypt} function encrypts @var{block} if |
| +@var{edflag} is 0, otherwise it decrypts @var{block}, using a key |
| +previously set by @code{setkey}. The result is |
| +placed in @var{block}. |
| + |
| +Like @code{setkey}, @var{block} is specified as an array of 64 bits each |
| +stored in a @code{char}, but there are no parity bits in @var{block}. |
| +@end deftypefun |
| + |
| +@deftypefun void setkey_r (const char *@var{key}, {struct crypt_data *} @var{data}) |
| +@deftypefunx void encrypt_r (char *@var{block}, int @var{edflag}, {struct crypt_data *} @var{data}) |
| +@standards{GNU, crypt.h} |
| +@c setkey_r: @safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{} @asulock{}}@acunsafe{@aculock{}}} |
| +@safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{} @asulock{}}@acunsafe{@aculock{}}} |
| + |
| +These are reentrant versions of @code{setkey} and @code{encrypt}. The |
| +only difference is the extra parameter, which stores the expanded |
| +version of @var{key}. Before calling @code{setkey_r} the first time, |
| +@code{data->initialized} must be cleared to zero. |
| +@end deftypefun |
| + |
| +The @code{setkey_r} and @code{encrypt_r} functions are GNU extensions. |
| +@code{setkey}, @code{encrypt}, @code{setkey_r}, and @code{encrypt_r} are |
| +defined in @file{crypt.h}. |
| + |
| +@deftypefun int ecb_crypt (char *@var{key}, char *@var{blocks}, unsigned int @var{len}, unsigned int @var{mode}) |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
| + |
| +The function @code{ecb_crypt} encrypts or decrypts one or more blocks |
| +using DES. Each block is encrypted independently. |
| + |
| +The @var{blocks} and the @var{key} are stored packed in 8-bit bytes, so |
| +that the first bit of the key is the most-significant bit of |
| +@code{key[0]} and the 63rd bit of the key is stored as the |
| +least-significant bit of @code{key[7]}. The @var{key} should have the |
| +correct parity. |
| + |
| +@var{len} is the number of bytes in @var{blocks}. It should be a |
| +multiple of 8 (so that there are a whole number of blocks to encrypt). |
| +@var{len} is limited to a maximum of @code{DES_MAXDATA} bytes. |
| + |
| +The result of the encryption replaces the input in @var{blocks}. |
| + |
| +The @var{mode} parameter is the bitwise OR of two of the following: |
| + |
| +@vtable @code |
| +@item DES_ENCRYPT |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +This constant, used in the @var{mode} parameter, specifies that |
| +@var{blocks} is to be encrypted. |
| + |
| +@item DES_DECRYPT |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +This constant, used in the @var{mode} parameter, specifies that |
| +@var{blocks} is to be decrypted. |
| + |
| +@item DES_HW |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +This constant, used in the @var{mode} parameter, asks to use a hardware |
| +device. If no hardware device is available, encryption happens anyway, |
| +but in software. |
| + |
| +@item DES_SW |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +This constant, used in the @var{mode} parameter, specifies that no |
| +hardware device is to be used. |
| +@end vtable |
| + |
| +The result of the function will be one of these values: |
| + |
| +@vtable @code |
| +@item DESERR_NONE |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +The encryption succeeded. |
| + |
| +@item DESERR_NOHWDEVICE |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +The encryption succeeded, but there was no hardware device available. |
| + |
| +@item DESERR_HWERROR |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +The encryption failed because of a hardware problem. |
| + |
| +@item DESERR_BADPARAM |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +The encryption failed because of a bad parameter, for instance @var{len} |
| +is not a multiple of 8 or @var{len} is larger than @code{DES_MAXDATA}. |
| +@end vtable |
| +@end deftypefun |
| + |
| +@deftypefun int DES_FAILED (int @var{err}) |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
| +This macro returns 1 if @var{err} is a `success' result code from |
| +@code{ecb_crypt} or @code{cbc_crypt}, and 0 otherwise. |
| +@end deftypefun |
| + |
| +@deftypefun int cbc_crypt (char *@var{key}, char *@var{blocks}, unsigned int @var{len}, unsigned int @var{mode}, char *@var{ivec}) |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
| + |
| +The function @code{cbc_crypt} encrypts or decrypts one or more blocks |
| +using DES in Cipher Block Chaining mode. |
| + |
| +For encryption in CBC mode, each block is exclusive-ored with @var{ivec} |
| +before being encrypted, then @var{ivec} is replaced with the result of |
| +the encryption, then the next block is processed. Decryption is the |
| +reverse of this process. |
| + |
| +This has the advantage that blocks which are the same before being |
| +encrypted are very unlikely to be the same after being encrypted, making |
| +it much harder to detect patterns in the data. |
| + |
| +Usually, @var{ivec} is set to 8 random bytes before encryption starts. |
| +Then the 8 random bytes are transmitted along with the encrypted data |
| +(without themselves being encrypted), and passed back in as @var{ivec} |
| +for decryption. Another possibility is to set @var{ivec} to 8 zeroes |
| +initially, and have the first block encrypted consist of 8 random |
| +bytes. |
| + |
| +Otherwise, all the parameters are similar to those for @code{ecb_crypt}. |
| +@end deftypefun |
| + |
| +@deftypefun void des_setparity (char *@var{key}) |
| +@standards{SUNRPC, rpc/des_crypt.h} |
| +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
| + |
| +The function @code{des_setparity} changes the 64-bit @var{key}, stored |
| +packed in 8-bit bytes, to have odd parity by altering the low bits of |
| +each byte. |
| +@end deftypefun |
| + |
| +The @code{ecb_crypt}, @code{cbc_crypt}, and @code{des_setparity} |
| +functions and their accompanying macros are all defined in the header |
| +@file{rpc/des_crypt.h}. |
| + |
| +@node Unpredictable Bytes |
| +@section Generating Unpredictable Bytes |
| + |
| The next program demonstrates how to verify a passphrase. It checks a |
| hash hardcoded into the program, because looking up real users' hashed |
| passphrases may require special privileges (@pxref{User Database}). |
| --- a/manual/string.texi |
| +++ b/manual/string.texi |
| @@ -36,8 +36,8 @@ too. |
| for delimiters. |
| * Erasing Sensitive Data:: Clearing memory which contains sensitive |
| data, after it's no longer needed. |
| -* Shuffling Bytes:: Or how to flash-cook a string. |
| -* Obfuscating Data:: Reversibly obscuring data from casual view. |
| +* strfry:: Function for flash-cooking a string. |
| +* Trivial Encryption:: Obscuring data. |
| * Encode Binary Data:: Encoding and Decoding of Binary Data. |
| * Argz and Envz Vectors:: Null-separated string vectors. |
| @end menu |
| @@ -2512,73 +2512,73 @@ functionality under a different name, su |
| systems it may be in @file{strings.h} instead. |
| @end deftypefun |
| |
| - |
| -@node Shuffling Bytes |
| -@section Shuffling Bytes |
| +@node strfry |
| +@section strfry |
| |
| The function below addresses the perennial programming quandary: ``How do |
| I take good data in string form and painlessly turn it into garbage?'' |
| -This is not a difficult thing to code for oneself, but the authors of |
| -@theglibc{} wish to make it as convenient as possible. |
| +This is actually a fairly simple task for C programmers who do not use |
| +@theglibc{} string functions, but for programs based on @theglibc{}, |
| +the @code{strfry} function is the preferred method for |
| +destroying string data. |
| |
| -To @emph{erase} data, use @code{explicit_bzero} (@pxref{Erasing |
| -Sensitive Data}); to obfuscate it reversibly, use @code{memfrob} |
| -(@pxref{Obfuscating Data}). |
| +The prototype for this function is in @file{string.h}. |
| |
| @deftypefun {char *} strfry (char *@var{string}) |
| @standards{GNU, string.h} |
| @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
| @c Calls initstate_r, time, getpid, strlen, and random_r. |
| |
| -@code{strfry} performs an in-place shuffle on @var{string}. Each |
| -character is swapped to a position selected at random, within the |
| -portion of the string starting with the character's original position. |
| -(This is the Fisher-Yates algorithm for unbiased shuffling.) |
| - |
| -Calling @code{strfry} will not disturb any of the random number |
| -generators that have global state (@pxref{Pseudo-Random Numbers}). |
| +@code{strfry} creates a pseudorandom anagram of a string, replacing the |
| +input with the anagram in place. For each position in the string, |
| +@code{strfry} swaps it with a position in the string selected at random |
| +(from a uniform distribution). The two positions may be the same. |
| |
| The return value of @code{strfry} is always @var{string}. |
| |
| @strong{Portability Note:} This function is unique to @theglibc{}. |
| -It is declared in @file{string.h}. |
| + |
| @end deftypefun |
| |
| |
| -@node Obfuscating Data |
| -@section Obfuscating Data |
| +@node Trivial Encryption |
| +@section Trivial Encryption |
| +@cindex encryption |
| + |
| + |
| +The @code{memfrob} function converts an array of data to something |
| +unrecognizable and back again. It is not encryption in its usual sense |
| +since it is easy for someone to convert the encrypted data back to clear |
| +text. The transformation is analogous to Usenet's ``Rot13'' encryption |
| +method for obscuring offensive jokes from sensitive eyes and such. |
| +Unlike Rot13, @code{memfrob} works on arbitrary binary data, not just |
| +text. |
| @cindex Rot13 |
| |
| -The @code{memfrob} function reversibly obfuscates an array of binary |
| -data. This is not true encryption; the obfuscated data still bears a |
| -clear relationship to the original, and no secret key is required to |
| -undo the obfuscation. It is analogous to the ``Rot13'' cipher used on |
| -Usenet for obscuring offensive jokes, spoilers for works of fiction, |
| -and so on, but it can be applied to arbitrary binary data. |
| - |
| -Programs that need true encryption---a transformation that completely |
| -obscures the original and cannot be reversed without knowledge of a |
| -secret key---should use a dedicated cryptography library, such as |
| -@uref{https://www.gnu.org/software/libgcrypt/,,libgcrypt}. |
| - |
| -Programs that need to @emph{destroy} data should use |
| -@code{explicit_bzero} (@pxref{Erasing Sensitive Data}), or possibly |
| -@code{strfry} (@pxref{Shuffling Bytes}). |
| +For true encryption, @xref{Cryptographic Functions}. |
| + |
| +This function is declared in @file{string.h}. |
| +@pindex string.h |
| |
| @deftypefun {void *} memfrob (void *@var{mem}, size_t @var{length}) |
| @standards{GNU, string.h} |
| @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
| |
| -The function @code{memfrob} obfuscates @var{length} bytes of data |
| -beginning at @var{mem}, in place. Each byte is bitwise xor-ed with |
| -the binary pattern 00101010 (hexadecimal 0x2A). The return value is |
| -always @var{mem}. |
| - |
| -@code{memfrob} a second time on the same data returns it to |
| -its original state. |
| +@code{memfrob} transforms (frobnicates) each byte of the data structure |
| +at @var{mem}, which is @var{length} bytes long, by bitwise exclusive |
| +oring it with binary 00101010. It does the transformation in place and |
| +its return value is always @var{mem}. |
| + |
| +Note that @code{memfrob} a second time on the same data structure |
| +returns it to its original state. |
| + |
| +This is a good function for hiding information from someone who doesn't |
| +want to see it or doesn't want to see it very much. To really prevent |
| +people from retrieving the information, use stronger encryption such as |
| +that described in @xref{Cryptographic Functions}. |
| |
| @strong{Portability Note:} This function is unique to @theglibc{}. |
| -It is declared in @file{string.h}. |
| + |
| @end deftypefun |
| |
| @node Encode Binary Data |
| --- a/posix/unistd.h |
| +++ b/posix/unistd.h |
| @@ -107,6 +107,9 @@ __BEGIN_DECLS |
| /* The X/Open Unix extensions are available. */ |
| #define _XOPEN_UNIX 1 |
| |
| +/* Encryption is present. */ |
| +#define _XOPEN_CRYPT 1 |
| + |
| /* The enhanced internationalization capabilities according to XPG4.2 |
| are present. */ |
| #define _XOPEN_ENH_I18N 1 |
| @@ -1150,17 +1153,25 @@ ssize_t copy_file_range (int __infd, __o |
| extern int fdatasync (int __fildes); |
| #endif /* Use POSIX199309 */ |
| |
| -#ifdef __USE_MISC |
| +/* XPG4.2 specifies that prototypes for the encryption functions must |
| + be defined here. */ |
| +#ifdef __USE_XOPEN |
| /* One-way hash PHRASE, returning a string suitable for storage in the |
| user database. SALT selects the one-way function to use, and |
| ensures that no two users' hashes are the same, even if they use |
| the same passphrase. The return value points to static storage |
| which will be overwritten by the next call to crypt. */ |
| + |
| +/* Encrypt at most 8 characters from KEY using salt to perturb DES. */ |
| extern char *crypt (const char *__key, const char *__salt) |
| __THROW __nonnull ((1, 2)); |
| -#endif |
| |
| -#ifdef __USE_XOPEN |
| +/* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt |
| + block in place. */ |
| +extern void encrypt (char *__glibc_block, int __edflag) |
| + __THROW __nonnull ((1)); |
| + |
| + |
| /* Swab pairs bytes in the first N bytes of the area pointed to by |
| FROM and copy the result to TO. The value of TO must not be in the |
| range [FROM - N + 1, FROM - 1]. If N is odd the first byte in FROM |
| --- a/stdlib/stdlib.h |
| +++ b/stdlib/stdlib.h |
| @@ -1103,6 +1103,12 @@ extern int getsubopt (char **__restrict |
| #endif |
| |
| |
| +#ifdef __USE_XOPEN |
| +/* Setup DES tables according KEY. */ |
| +extern void setkey (const char *__key) __THROW __nonnull ((1)); |
| +#endif |
| + |
| + |
| /* X/Open pseudo terminal handling. */ |
| |
| #ifdef __USE_XOPEN2KXSI |
| --- a/sunrpc/des_crypt.c |
| +++ b/sunrpc/des_crypt.c |
| @@ -86,9 +86,6 @@ common_crypt (char *key, char *buf, regi |
| return desdev == DES_SW ? DESERR_NONE : DESERR_NOHWDEVICE; |
| } |
| |
| -/* Note: these cannot be excluded from the build yet, because they are |
| - still used internally. */ |
| - |
| /* |
| * CBC mode encryption |
| */ |
| @@ -105,7 +102,7 @@ cbc_crypt (char *key, char *buf, unsigne |
| COPY8 (dp.des_ivec, ivec); |
| return err; |
| } |
| -hidden_nolink (cbc_crypt, libc, GLIBC_2_1) |
| +libc_hidden_nolink_sunrpc (cbc_crypt, GLIBC_2_1) |
| |
| /* |
| * ECB mode encryption |
| @@ -118,4 +115,4 @@ ecb_crypt (char *key, char *buf, unsigne |
| dp.des_mode = ECB; |
| return common_crypt (key, buf, len, mode, &dp); |
| } |
| -hidden_nolink (ecb_crypt, libc, GLIBC_2_1) |
| +libc_hidden_nolink_sunrpc (ecb_crypt, GLIBC_2_1) |
| --- a/sunrpc/des_soft.c |
| +++ b/sunrpc/des_soft.c |
| @@ -71,4 +71,4 @@ des_setparity (char *p) |
| p++; |
| } |
| } |
| -hidden_nolink (des_setparity, libc, GLIBC_2_1) |
| +libc_hidden_nolink_sunrpc (des_setparity, GLIBC_2_1) |