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postfix-3.8-20220129

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This commit is contained in:
Wietse Venema 2022-01-29 00:00:00 -05:00 committed by Viktor Dukhovni
parent 50247b25ed
commit c3bcf4783e
10 changed files with 241 additions and 126 deletions
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12
postfix/HISTORY
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@ -26258,6 +26258,12 @@ Apologies for any names omitted.
20220128
Clenaup: standardize on FNV hash, having verified that
collisions will depend on the hash seed value, and that the
collision rate is low. Files: util/htable.c, util/fnv_hash.[hc].
Clenaup: standardize on FNV hash, after having verified
that collisions will change with the hash seed value, and
that the collision rate is low. Files: util/htable.c,
util/hash_fnv.[hc].
20220129
Cleanup: factored out the non-cryptographic seeder. Files:
ldseed.[hc].

1
postfix/proto/stop.double-cc
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@ -327,3 +327,4 @@ more more useful and more consistent
Fatal error error opening existing file
XXX XXX
int compar DNS_RR DNS_RR
NO_64_BITS NO_64_BITS

11
postfix/proto/stop.spell-cc
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@ -1770,3 +1770,14 @@ vars
verboten
versioning
wiki
DSTRICT
FNV
NONBLOCK
Vo
chongo
fnv
isthe
ldseed
softwareengineering
stackexchange
stdint

2
postfix/src/global/mail_version.h
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@ -20,7 +20,7 @@
* Patches change both the patchlevel and the release date. Snapshots have no
* patchlevel; they change the release date only.
*/
#define MAIL_RELEASE_DATE "20220128"
#define MAIL_RELEASE_DATE "20220129"
#define MAIL_VERSION_NUMBER "3.8"
#ifdef SNAPSHOT

12
postfix/src/util/Makefile.in
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@ -43,7 +43,7 @@ SRCS = alldig.c allprint.c argv.c argv_split.c attr_clnt.c attr_print0.c \
split_qnameval.c argv_attr_print.c argv_attr_scan.c dict_file.c \
msg_logger.c logwriter.c unix_dgram_connect.c unix_dgram_listen.c \
byte_mask.c known_tcp_ports.c argv_split_at.c dict_stream.c \
sane_strtol.c hash_fnv.c
sane_strtol.c hash_fnv.c ldseed.c
OBJS = alldig.o allprint.o argv.o argv_split.o attr_clnt.o attr_print0.o \
attr_print64.o attr_print_plain.o attr_scan0.o attr_scan64.o \
attr_scan_plain.o auto_clnt.o base64_code.o basename.o binhash.o \
@ -88,7 +88,7 @@ OBJS = alldig.o allprint.o argv.o argv_split.o attr_clnt.o attr_print0.o \
split_qnameval.o argv_attr_print.o argv_attr_scan.o dict_file.o \
msg_logger.o logwriter.o unix_dgram_connect.o unix_dgram_listen.o \
byte_mask.o known_tcp_ports.o argv_split_at.o dict_stream.o \
sane_strtol.o hash_fnv.o
sane_strtol.o hash_fnv.o ldseed.o
# MAP_OBJ is for maps that may be dynamically loaded with dynamicmaps.cf.
# When hard-linking these, makedefs sets NON_PLUGIN_MAP_OBJ=$(MAP_OBJ),
# otherwise it sets the PLUGIN_* macros.
@ -119,7 +119,7 @@ HDRS = argv.h attr.h attr_clnt.h auto_clnt.h base64_code.h binhash.h \
slmdb.h compat_va_copy.h dict_pipe.h dict_random.h \
valid_utf8_hostname.h midna_domain.h dict_union.h dict_inline.h \
check_arg.h argv_attr.h msg_logger.h logwriter.h byte_mask.h \
known_tcp_ports.h sane_strtol.h hash_fnv.h
known_tcp_ports.h sane_strtol.h hash_fnv.h ldseed.h
TESTSRC = fifo_open.c fifo_rdwr_bug.c fifo_rdonly_bug.c select_bug.c \
stream_test.c dup2_pass_on_exec.c
DEFS = -I. -D$(SYSTYPE)
@ -1909,6 +1909,7 @@ get_hostname.o: sys_defs.h
get_hostname.o: valid_hostname.h
hash_fnv.o: hash_fnv.c
hash_fnv.o: hash_fnv.h
hash_fnv.o: ldseed.h
hash_fnv.o: msg.h
hash_fnv.o: sys_defs.h
hex_code.o: check_arg.h
@ -2038,6 +2039,10 @@ known_tcp_ports.o: stringops.h
known_tcp_ports.o: sys_defs.h
known_tcp_ports.o: vbuf.h
known_tcp_ports.o: vstring.h
ldseed.o: iostuff.h
ldseed.o: ldseed.c
ldseed.o: msg.h
ldseed.o: sys_defs.h
line_number.o: check_arg.h
line_number.o: line_number.c
line_number.o: line_number.h
@ -2541,6 +2546,7 @@ stream_trigger.o: mymalloc.h
stream_trigger.o: stream_trigger.c
stream_trigger.o: sys_defs.h
stream_trigger.o: trigger.h
sys_compat.o: iostuff.h
sys_compat.o: sys_compat.c
sys_compat.o: sys_defs.h
timecmp.o: timecmp.c

126
postfix/src/util/hash_fnv.c
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@ -10,21 +10,27 @@
/* const void *src,
/* size_t len)
/* DESCRIPTION
/* hash_fnv() implements the FNV type 1a hash function.
/* hash_fnv() implements a modified FNV type 1a hash function.
/*
/* To thwart collision attacks, the hash function is seeded
/* once from /dev/urandom, and if that is unavailable, from
/* wallclock time, monotonic system clocks, and the process
/* ID. To disable seeding in tests, specify the NORANDOMIZE
/* environment variable (the value does not matter).
/* ID. To disable seeding (typically, for regression tests),
/* specify the NORANDOMIZE environment variable; the value
/* does not matter.
/*
/* By default, the function is modified to avoid a sticky state
/* where a zero hash value remains zero when the next input
/* byte value is zero. Compile with -DSTRICT_FNV1A to get the
/* standard behavior.
/* This function implements a workaround for a "sticky state"
/* problem with FNV hash functions: when an input produces a
/* zero intermediate hash state, and the next input byte is
/* zero, then the operations "hash ^= 0" and "hash *= FNV_prime"
/* would not change the hash value. To avoid this, hash_fnv()
/* adds 1 to each input byte. Compile with -DSTRICT_FNV1A to
/* get the standard behavior.
/*
/* The default HASH_FNV_T result type is uint64_t. When compiled
/* with -DNO_64_BITS, the result type is uint32_t.
/* with -DNO_64_BITS, the result type is uint32_t. On ancient
/* systems without <stdint.h>, define HASH_FNV_T on the compiler
/* command line as an unsigned 32-bit or 64-bit integer type.
/* SEE ALSO
/* http://www.isthe.com/chongo/tech/comp/fnv/index.html
/* https://softwareengineering.stackexchange.com/questions/49550/
@ -43,17 +49,14 @@
* System library
*/
#include <sys_defs.h>
#include <string.h>
#include <sys/time.h>
#include <time.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
/*
* Utility library.
*/
#include <msg.h>
#include <ldseed.h>
#include <hash_fnv.h>
/*
@ -67,80 +70,6 @@
#define FNV_offset_basis 0xcbf29ce484222325ULL
#endif
/*
* Fall back to a mix of absolute and time-since-boot information in the
* rare case that /dev/urandom is unavailable.
*/
#ifdef CLOCK_UPTIME
#define NON_WALLTIME_CLOCK CLOCK_UPTIME
#elif defined(CLOCK_BOOTTIME)
#define NON_WALLTIME_CLOCK CLOCK_BOOTTIME
#elif defined(CLOCK_MONOTONIC)
#define NON_WALLTIME_CLOCK CLOCK_MONOTONIC
#elif defined(CLOCK_HIGHRES)
#define NON_WALLTIME_CLOCK CLOCK_HIGHRES
#endif
/* fnv_seed - randomize the hash function */
static HASH_FNV_T fnv_seed(void)
{
HASH_FNV_T result = 0;
/*
* Medium-quality seed, for defenses against local and remote attacks.
*/
int fd;
int count;
if ((fd = open("/dev/urandom", O_RDONLY)) > 0) {
count = read(fd, &result, sizeof(result));
(void) close(fd);
if (count == sizeof(result) && result != 0)
return (result);
}
/*
* Low-quality seed, for defenses against remote attacks. Based on 1) the
* time since boot (good when an attacker knows the program start time
* but not the system boot time), and 2) absolute time (good when an
* attacker does not know the program start time). Assumes a system with
* better than microsecond resolution, and a network stack that does not
* leak the time since boot, for example, through TCP or ICMP timestamps.
* With those caveats, this seed is good for 20-30 bits of randomness.
*/
#ifdef NON_WALLTIME_CLOCK
{
struct timespec ts;
if (clock_gettime(NON_WALLTIME_CLOCK, &ts) != 0)
msg_fatal("clock_gettime() failed: %m");
result += (HASH_FNV_T) ts.tv_sec ^ (HASH_FNV_T) ts.tv_nsec;
}
#elif defined(USE_GETHRTIME)
result += gethrtime();
#endif
#ifdef CLOCK_REALTIME
{
struct timespec ts;
if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
msg_fatal("clock_gettime() failed: %m");
result += (HASH_FNV_T) ts.tv_sec ^ (HASH_FNV_T) ts.tv_nsec;
}
#else
{
struct timeval tv;
if (GETTIMEOFDAY(&tv) != 0)
msg_fatal("gettimeofday() failed: %m");
result += (HASH_FNV_T) tv.tv_sec + (HASH_FNV_T) tv.tv_usec;
}
#endif
return (result + getpid());
}
/* hash_fnv - modified FNV 1a hash */
HASH_FNV_T hash_fnv(const void *src, size_t len)
@ -152,30 +81,25 @@ HASH_FNV_T hash_fnv(const void *src, size_t len)
/*
* Initialize.
*/
while (randomize) {
if (getenv("NORANDOMIZE")) {
randomize = 0;
} else {
basis ^= fnv_seed();
if (basis != FNV_offset_basis)
randomize = 0;
if (randomize) {
if (!getenv("NORANDOMIZE")) {
HASH_FNV_T seed;
ldseed(&seed, sizeof(seed));
basis ^= seed;
}
randomize = 0;
}
/*
* Add 1 to each input character, to avoid a sticky state (with hash ==
* 0, doing "hash ^= 0" and "hash *= FNV_prime" would not change the hash
* value.
*/
#ifdef STRICT_FNV1A
#define FNV_NEXT_CHAR(s) ((HASH_FNV_T) * (const unsigned char *) s++)
#define FNV_NEXT_BYTE(s) ((HASH_FNV_T) * (const unsigned char *) s++)
#else
#define FNV_NEXT_CHAR(s) (1 + (HASH_FNV_T) * (const unsigned char *) s++)
#define FNV_NEXT_BYTE(s) (1 + (HASH_FNV_T) * (const unsigned char *) s++)
#endif
hash = basis;
while (len-- > 0) {
hash ^= FNV_NEXT_CHAR(src);
hash ^= FNV_NEXT_BYTE(src);
hash *= FNV_prime;
}
return (hash);

16
postfix/src/util/hash_fnv.h
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@ -11,21 +11,17 @@
/* DESCRIPTION
/* .nf
/*
* Systemn library.
*/
#ifndef NO_STDINT_H
#include <stdint.h>
#endif
/*
* External interface.
*/
#ifndef HASH_FNV_T
#include <stdint.h>
#ifdef NO_64_BITS
#define HASH_FNV_T uint32_t
#else
#define HASH_FNV_T uint64_t
#endif
#else /* NO_64_BITS */
#define HASH_FNV_T uint64_t
#endif /* NO_64_BITS */
#endif /* HASH_FNV_T */
extern HASH_FNV_T hash_fnv(const void *, size_t);

20
postfix/src/util/htable.c
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@ -113,6 +113,11 @@
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/* C library */
@ -124,14 +129,12 @@
#include "mymalloc.h"
#include "msg.h"
#ifndef NO_HASH_FNV
#include "hash_fnv.h"
#endif
#include "htable.h"
/* htable_hash - hash a string */
#ifndef NO_HASH_FNV
#include "hash_fnv.h"
#define htable_hash(s, size) (hash_fnv((s), strlen(s)) % (size))
@ -147,14 +150,15 @@ static size_t htable_hash(const char *s, size_t size)
*/
while (*s) {
h = (h << 4U) + *(unsigned const char *) s++;
if ((g = (h & 0xf0000000)) != 0) {
h ^= (g >> 24U);
h ^= g;
}
h = (h << 4U) + *(unsigned const char *) s++;
if ((g = (h & 0xf0000000)) != 0) {
h ^= (g >> 24U);
h ^= g;
}
}
return (h % size);
}
#endif
/* htable_link - insert element into table */

137
postfix/src/util/ldseed.c Normal file
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@ -0,0 +1,137 @@
/*++
/* NAME
/* ldseed 3
/* SUMMARY
/* seed for non-cryptographic applications
/* SYNOPSIS
/* #include <ldseed.h>
/*
/* void ldseed(
/* void *dst,
/* size_t len)
/* DESCRIPTION
/* ldseed() preferably extracts pseudo-random bits from
/* /dev/urandom, a non-blocking device that is available on
/* modern systems.
/*
/* On systems where /dev/urandom is unavailable or does not
/* immediately return the requested amount of randomness,
/* ldseed() falls back to a combination of wallclock time,
/* the time since boot, and the process ID.
/* BUGS
/* With Linux "the O_NONBLOCK flag has no effect when opening
/* /dev/urandom", but reads "can incur an appreciable delay
/* when requesting large amounts of data". Apparently, "large"
/* means more than 256 bytes.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/*
* System library
*/
#include <sys_defs.h>
#include <string.h>
#include <sys/time.h>
#include <time.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <limits.h> /* CHAR_BIT */
/*
* Utility library.
*/
#include <iostuff.h>
#include <msg.h>
/*
* Different systems have different names for non-wallclock time.
*/
#ifdef CLOCK_UPTIME
#define NON_WALLTIME_CLOCK CLOCK_UPTIME
#elif defined(CLOCK_BOOTTIME)
#define NON_WALLTIME_CLOCK CLOCK_BOOTTIME
#elif defined(CLOCK_MONOTONIC)
#define NON_WALLTIME_CLOCK CLOCK_MONOTONIC
#elif defined(CLOCK_HIGHRES)
#define NON_WALLTIME_CLOCK CLOCK_HIGHRES
#endif
/* ldseed - best-effort, low-dependency seed */
void ldseed(void *dst, size_t len)
{
int count;
int fd;
int n;
time_t fallback = 0;
/*
* Medium-quality seed.
*/
if ((fd = open("/dev/urandom", O_RDONLY)) > 0) {
non_blocking(fd, NON_BLOCKING);
count = read(fd, dst, len);
(void) close(fd);
if (count == len)
return;
}
/*
* Low-quality seed. Based on 1) the time since boot (good when an
* attacker knows the program start time but not the system boot time),
* and 2) absolute time (good when an attacker does not know the program
* start time). Assumes a system with better than microsecond resolution,
* and a network stack that does not leak the time since boot, for
* example, through TCP or ICMP timestamps. With those caveats, this seed
* is good for 20-30 bits of randomness.
*/
#ifdef NON_WALLTIME_CLOCK
{
struct timespec ts;
if (clock_gettime(NON_WALLTIME_CLOCK, &ts) != 0)
msg_fatal("clock_gettime() failed: %m");
fallback += ts.tv_sec ^ ts.tv_nsec;
}
#elif defined(USE_GETHRTIME)
fallback += gethrtime();
#endif
#ifdef CLOCK_REALTIME
{
struct timespec ts;
if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
msg_fatal("clock_gettime() failed: %m");
fallback += ts.tv_sec ^ ts.tv_nsec;
}
#else
{
struct timeval tv;
if (GETTIMEOFDAY(&tv) != 0)
msg_fatal("gettimeofday() failed: %m");
fallback += tv.tv_sec + tv.tv_usec;
}
#endif
fallback += getpid();
/*
* Copy the least significant bytes first, because those are the most
* volatile.
*/
for (n = 0; n < sizeof(fallback) && n < len; n++) {
*(char *) dst++ ^= (fallback & 0xff);
fallback >>= CHAR_BIT;
}
return;
}

30
postfix/src/util/ldseed.h Normal file
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@ -0,0 +1,30 @@
#ifndef _LDSEED_H_INCLUDED_
#define _LDSEED_H_INCLUDED_
/*++
/* NAME
/* ldseed 3h
/* SUMMARY
/* seed for non-cryptographic applications
/* SYNOPSIS
/* #include <ldseed.h>
/* DESCRIPTION
/* .nf
/*
* External interface.
*/
extern void ldseed(void *, size_t);
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
#endif