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Merge branch 'nonblock-fail-getrandom' (pull request #92)

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This commit is contained in:
Sebastian Pipping 2017-07-29 15:17:10 +02:00
commit ce5f210785
2 changed files with 52 additions and 5 deletions
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5
expat/Changes
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@ -12,14 +12,19 @@ Release 2.2.? ????????????????
Other changes:
Increase code coverage
#91 Linux: Allow getrandom to fail if nonblocking pool has not
yet been initialized and read /dev/urandom then, instead.
This is in line with what recent Python does.
#23 Test suite: Fix memory leaks
Rely on macro HAVE_ARC4RANDOM_BUF (rather than __CloudABI__)
for CloudABI
#100 Fix use of SIPHASH_MAIN in siphash.h
Special thanks to:
Chanho Park
Pascal Cuoq
Rhodri James
Simon McVittie
Vadim Zeitlin
Viktor Szakats
and

52
expat/lib/xmlparse.c
View file

@ -21,6 +21,8 @@
#include <sys/time.h> /* gettimeofday() */
#include <sys/types.h> /* getpid() */
#include <unistd.h> /* getpid() */
#include <fcntl.h> /* O_RDONLY */
#include <errno.h>
#endif
#define XML_BUILDING_EXPAT 1
@ -36,13 +38,15 @@
#include "siphash.h"
#if defined(HAVE_GETRANDOM) || defined(HAVE_SYSCALL_GETRANDOM)
# include <errno.h>
# if defined(HAVE_GETRANDOM)
# include <sys/random.h> /* getrandom */
# else
# include <unistd.h> /* syscall */
# include <sys/syscall.h> /* SYS_getrandom */
# endif
# if ! defined(GRND_NONBLOCK)
# define GRND_NONBLOCK 0x0001
# endif /* defined(GRND_NONBLOCK) */
#endif /* defined(HAVE_GETRANDOM) || defined(HAVE_SYSCALL_GETRANDOM) */
#if defined(HAVE_LIBBSD) \
@ -751,10 +755,10 @@ static const XML_Char implicitContext[] = {
/* Obtain entropy on Linux 3.17+ */
static int
writeRandomBytes_getrandom(void * target, size_t count) {
writeRandomBytes_getrandom_nonblock(void * target, size_t count) {
int success = 0; /* full count bytes written? */
size_t bytesWrittenTotal = 0;
const unsigned int getrandomFlags = 0;
const unsigned int getrandomFlags = GRND_NONBLOCK;
do {
void * const currentTarget = (void*)((char*)target + bytesWrittenTotal);
@ -772,7 +776,7 @@ writeRandomBytes_getrandom(void * target, size_t count) {
if (bytesWrittenTotal >= count)
success = 1;
}
} while (! success && (errno == EINTR || errno == EAGAIN));
} while (! success && (errno == EINTR));
return success;
}
@ -780,6 +784,39 @@ writeRandomBytes_getrandom(void * target, size_t count) {
#endif /* defined(HAVE_GETRANDOM) || defined(HAVE_SYSCALL_GETRANDOM) */
#if ! defined(_WIN32)
/* Extract entropy from /dev/urandom */
static int
writeRandomBytes_dev_urandom(void * target, size_t count) {
int success = 0; /* full count bytes written? */
size_t bytesWrittenTotal = 0;
const int fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
return 0;
}
do {
void * const currentTarget = (void*)((char*)target + bytesWrittenTotal);
const size_t bytesToWrite = count - bytesWrittenTotal;
const ssize_t bytesWrittenMore = read(fd, currentTarget, bytesToWrite);
if (bytesWrittenMore > 0) {
bytesWrittenTotal += bytesWrittenMore;
if (bytesWrittenTotal >= count)
success = 1;
}
} while (! success && (errno == EINTR));
close(fd);
return success;
}
#endif /* ! defined(_WIN32) */
#if defined(HAVE_ARC4RANDOM)
static void
@ -898,10 +935,15 @@ generate_hash_secret_salt(XML_Parser parser)
return ENTROPY_DEBUG("RtlGenRandom", entropy);
}
#elif defined(HAVE_GETRANDOM) || defined(HAVE_SYSCALL_GETRANDOM)
if (writeRandomBytes_getrandom((void *)&entropy, sizeof(entropy))) {
if (writeRandomBytes_getrandom_nonblock((void *)&entropy, sizeof(entropy))) {
return ENTROPY_DEBUG("getrandom", entropy);
}
#endif
#if ! defined(_WIN32)
if (writeRandomBytes_dev_urandom((void *)&entropy, sizeof(entropy))) {
return ENTROPY_DEBUG("/dev/urandom", entropy);
}
#endif /* ! defined(_WIN32) */
/* .. and self-made low quality for backup: */
/* Process ID is 0 bits entropy if attacker has local access */