This is a major rewrite of the description of 'crypt', 'getentropy',
and 'getrandom'.
A few highlights of the content changes:
- Throughout the manual, public headers, and user-visible messages,
I replaced the term "password" with "passphrase", the term
"password database" with "user database", and the term
"encrypt(ion)" with "(one-way) hashing" whenever it was applied to
passphrases. I didn't bother making this change in internal code
or tests. The use of the term "password" in ruserpass.c survives,
because that refers to a keyword in netrc files, but it is adjusted
to make this clearer.
There is a note in crypt.texi explaining that they were
traditionally called passwords but single words are not good enough
anymore, and a note in users.texi explaining that actual passphrase
hashes are found in a "shadow" database nowadays.
- There is a new short introduction to the "Cryptographic Functions"
section, explaining how we do not intend to be a general-purpose
cryptography library, and cautioning that there _are_, or have
been, legal restrictions on the use of cryptography in many
countries, without getting into any kind of detail that we can't
promise to keep up to date.
- I added more detail about what a "one-way function" is, and why
they are used to obscure passphrases for storage. I removed the
paragraph saying that systems not connected to a network need no
user authentication, because that's a pretty rare situation
nowadays. (It still says "sometimes it is necessary" to
authenticate the user, though.)
- I added documentation for all of the hash functions that glibc
actually supports, but not for the additional hash functions
supported by libxcrypt. If we're going to keep this manual section
around after the transition is more advanced, it would probably
make sense to add them then.
- There is much more detailed discussion of how to generate a salt,
and the failure behavior for crypt is documented. (Returning an
invalid hash on failure is what libxcrypt does; Solar Designer's
notes say that this was done "for compatibility with old programs
that assume crypt can never fail".)
- As far as I can tell, the header 'crypt.h' is entirely a GNU
invention, and never existed on any other Unix lineage. The
function 'crypt', however, was in Issue 1 of the SVID and is now
in the XSI component of POSIX. I tried to make all of the
@standards annotations consistent with this, but I'm not sure I got
them perfectly right.
- The genpass.c example has been improved to use getentropy instead
of the current time to generate the salt, and to use a SHA-256 hash
instead of MD5. It uses more random bytes than is strictly
necessary because I didn't want to complicate the code with proper
base64 encoding.
- The testpass.c example has three hardwired hashes now, to
demonstrate that different one-way functions produce different
hashes for the same input. It also demonstrates how DES hashing
only pays attention to the first eight characters of the input.
- There is new text explaining in more detail how a CSPRNG differs
from a regular random number generator, and how
getentropy/getrandom are not exactly a CSPRNG. I tried not to make
specific falsifiable claims here. I also tried to make the
blocking/cancellation/error behavior of both getentropy and
getrandom clearer.
This automatically-generated patch converts 29 function definitions in
glibc (including one in an example in the manual) from old-style K&R
to prototype-style. Following my other recent such patches, this one
deals with the case of function definitions where one K&R parameter
declaration declares multiple parameters, as in:
void
foo (a, b)
int a, *b;
{
}
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* crypt/crypt.c (_ufc_doit_r): Convert to prototype-style function
definition.
(_ufc_doit_r): Likewise.
* crypt/crypt_util.c (_ufc_copymem): Likewise.
(_ufc_output_conversion_r): Likewise.
* inet/inet_mkadr.c (__inet_makeaddr): Likewise.
* inet/rcmd.c (rcmd_af): Likewise.
(rcmd): Likewise.
(ruserok_af): Likewise.
(ruserok): Likewise.
(ruserok2_sa): Likewise.
(ruserok_sa): Likewise.
(iruserok_af): Likewise.
(iruserok): Likewise.
(__ivaliduser): Likewise.
(__validuser2_sa): Likewise.
* inet/rexec.c (rexec_af): Likewise.
(rexec): Likewise.
* inet/ruserpass.c (ruserpass): Likewise.
* locale/programs/xmalloc.c (xcalloc): Likewise.
* manual/examples/timeval_subtract.c (timeval_subtract): Likewise.
* math/w_drem.c (__drem): Likewise.
* math/w_dremf.c (__dremf): Likewise.
* math/w_dreml.c (__dreml): Likewise.
* misc/daemon.c (daemon): Likewise.
* resolv/res_debug.c (p_fqnname): Likewise.
* stdlib/div.c (div): Likewise.
* string/memcmp.c (memcmp_bytes): Likewise.
* sunrpc/pmap_rmt.c (pmap_rmtcall): Likewise.
* sunrpc/svc_udp.c (svcudp_bufcreate): Likewise.
1998-05-23 Philip Blundell <Philip.Blundell@pobox.com>
* sysdeps/unix/sysv/linux/arm/syscalls.list: Add `syscall'.
* sysdeps/unix/sysv/linux/arm/syscall.S: Deleted.
1998-07-05 Ulrich Drepper <drepper@cygnus.com>
* misc/getttyent.c (getttyent): Explicitly lock the FILE and use
_unlocked functions.
* inet/ruserpass.c (ruserpass): Use _unlocked functions since this
is a private FILE.
Sat Sep 28 03:02:49 1996 Ulrich Drepper <drepper@cygnus.com>
* dirent/Makefile (routines): Add readdir_r.
* dirent/readdir_r.c: New file. Wrapper around readdir.c.
* dirent/dirent.h: Add prototype for readdir_r.
* misc/hsearch_r.c (ENTRY): Make field `used' of type `unsigned int'
to prevent warnings.
* sysdeps/unix/sysv/linux/getsysstats.c (get_proc_path):
Initialize `result'.
Sat Sep 28 01:16:42 1996 Ulrich Drepper <drepper@cygnus.com>
* sysdeps/generic/strsep.c: Rename to __strsep and make strsep
weak alias.
* string/string.h: Add prototype for __strsep.
* misc/mntent_r.c: Use __strsep instead of strsep to keep
namespace clean.
* sysdeps/stub/nanosleep.c: Rename to __libc_nanosleep and make
__nanosleep and nanosleep weak aliases.
* sysdeps/unix/sysv/linux/syscalls.list: Add __nanosleep as weak
alias.
* sysdeps/unix/sysv/linux/sleep.c: Call __nanosleep instead of
nanosleep to keep namespace clean.
* sysdeps/posix/ttyname.c (ttyname): Add cast to prevent warning.
* sysdeps/posix/ttyname_r.c (ttyname_r): Likewise.
* sysdeps/posix/getcwd.c (__getcwd): Likewise.
* sysdeps/unix/nlist.c: Use ISO C definition since we don't always
have prototype.
* login/Makefile (headers): Add pty.h.
* login/pty.h: New file.
* sysdeps/generic/pty.h: Include <pty.h>.
* login/pututline_r.c: Add cast to prevent warning.
* gmon/gmon.c: Add prototype for __profile_frequency.
(monstartup): Add cast to prevent warning.
* sysdeps/generic/prof-freq.c: Change to use ISO C style definition.
* locale/programs/ld-time.c (time_output): Write `era' information
in correct order.
Sat Sep 28 00:11:08 1996 Ulrich Drepper <drepper@cygnus.com>
* sysdeps/unix/sysv/linux/syscalls.list: Add weak alias
`adjtimex'.
Set caller for mlock, mlockall, mremap, munlock, and munlockall
to EXTRA.
Reported by Matthias Urlichs <smurf@smurf.noris.de>.
1996-09-27 Paul Eggert <eggert@twinsun.com>
* strftime.c (strftime): Output incomplete formats like %E
at end of string.
1996-09-27 Paul Eggert <eggert@twinsun.com>
* strftime.c (strftime): Add support for %EC and %Ey.
Fix support for %EY. This uses the new _nl_get_era_entry function.
Fri Sep 27 14:12:27 1996 Ulrich Drepper <drepper@cygnus.com>
Security related patch by Elliot Lee <sopwith@redhat.com> and
David Holland <dholland@eecs.harvard.edu>.
* inet/rexec.c (rexec): Increase size of `num' array from 8 to 32.
* inet/ruserpass.c (ruserpass): Don't allow $HOME envvar to not exist.
* sysdeps/generic/getenv.c (__secure_getenv): New function. Return
NULL when programs runs with SUID or SGID enabled.
* sysdeps/stub/getenv.c: Make __secure_getenv an alias of getenv.
* stdlib/stdlib.h: Add prototype for __secure_getenv.
* locale/setlocale.c: Use __secure_getenv.
* resolv/res_init.c: Likewise.
* resolv/res_query.c: Likewise.
* inet/ruserpass.c: Likewise.
* sysdeps/posix/tempname.c: Likewise.
* malloc/mtrace.c: Likewise.
* catgets/catgets.c: Likewise.
Make temporary file handling functions reentrant.
* stdio-common/tmpnam.c: Rewrite to have own buffer to write
result to. The called __stdio_gen_tempname function must be
thread safe.
* stdio-common/tmpnam_r.c: New file.
* stdio/stdio.h: Add prototype for `tmpnam_r'.
Change prototype for __stdio_gen_tempname.
* stdio/libio.h: Likewise.
* sysdeps/posix/tempname.c: Add new parameters and use them instead
of static buffer.
Don't reset `indeces' when PID changed between calls.
Don't fail for long running programs when index counter once
reached the limit.
* sysdeps/stub/tempname.c: Likewise.
* stdio-common/tempnam.c: Provide local buffer as extra argument
to __stdio_gen_tempname. This makes this function reentrant.
* stdio-common/tmpfile.c: Likewise.
* stdio-common/temptest.c: Provide extra argument to
__stdio_gen_tempname.
* manual/filesys.texi: Describe tmpnam_r and add comments about
reentrancy of the functions.
* inet/rcmd.c: Fixed address length handling.
* sysdeps/posix/mk-stdiolim.c: Count final \0 byte in L_tmpnam value.
* time/strftime.c: Remove unused variables alt_digits and
end_alt_digits.
* sysdeps/unix/sysv/linux/sys/sysinfo.h: Correct prototype names
for get_nprocs and get_nprocs_conf.
* sysdeps/generic/sys/sysinfo.h: Likewise.
* stdlib/test-canon.c: Finally do the right fix.
* misc/Makefile: Only compile force-wrapper when compiling
reentrant libc.
