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Make EXPAT_ENTROPY_DEBUG=1 print entropy source and bytes

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Sebastian Pipping 2017-05-31 12:40:28 +02:00
parent ad8521ca84
commit 9e02465f09
2 changed files with 21 additions and 5 deletions
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1
expat/Changes
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@ -9,6 +9,7 @@ Release ??????????
In a way, that's still part of CVE-2016-5300.
For packaging, feel free to configure using
--(with|without)-libbsd to bypass auto-detection.
For run-time debug output, EXPAT_ENTROPY_DEBUG=1 can be used.
Bug fixes:
#539 Fix regression from fix to CVE-2016-0718 cutting off

25
expat/lib/xmlparse.c
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@ -6,6 +6,8 @@
#include <string.h> /* memset(), memcpy() */
#include <assert.h>
#include <limits.h> /* UINT_MAX */
#include <stdio.h> /* fprintf */
#include <stdlib.h> /* getenv */
#ifdef _WIN32
#define getpid GetCurrentProcessId
@ -783,6 +785,18 @@ gather_time_entropy(void)
# include <bsd/stdlib.h>
#endif
static unsigned long
ENTROPY_DEBUG(const char * label, unsigned long entropy) {
const char * const EXPAT_ENTROPY_DEBUG = getenv("EXPAT_ENTROPY_DEBUG");
if (EXPAT_ENTROPY_DEBUG && ! strcmp(EXPAT_ENTROPY_DEBUG, "1")) {
fprintf(stderr, "Entropy: %s --> 0x%0*lx (%lu bytes)\n",
label,
(int)sizeof(unsigned long) * 2, entropy,
sizeof(unsigned long));
}
return entropy;
}
static unsigned long
generate_hash_secret_salt(XML_Parser parser)
{
@ -791,16 +805,16 @@ generate_hash_secret_salt(XML_Parser parser)
#if defined(HAVE_ARC4RANDOM_BUF) || defined(__CloudABI__)
(void)gather_time_entropy;
arc4random_buf(&entropy, sizeof(entropy));
return entropy;
return ENTROPY_DEBUG("arc4random_buf", entropy);
#else
/* Try high quality providers first .. */
#ifdef _WIN32
if (writeRandomBytes_RtlGenRandom((void *)&entropy, sizeof(entropy))) {
return entropy;
return ENTROPY_DEBUG("RtlGenRandom", entropy);
}
#elif defined(HAVE_GETRANDOM)
if (writeRandomBytes_getrandom((void *)&entropy, sizeof(entropy))) {
return entropy;
return ENTROPY_DEBUG("getrandom", entropy);
}
#endif
/* .. and self-made low quality for backup: */
@ -810,9 +824,10 @@ generate_hash_secret_salt(XML_Parser parser)
/* Factors are 2^31-1 and 2^61-1 (Mersenne primes M31 and M61) */
if (sizeof(unsigned long) == 4) {
return entropy * 2147483647;
return ENTROPY_DEBUG("fallback(4)", entropy * 2147483647);
} else {
return entropy * (unsigned long)2305843009213693951;
return ENTROPY_DEBUG("fallback(8)",
entropy * (unsigned long)2305843009213693951);
}
#endif
}