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Merge "Ensure that the port number and TXID are properly randomized." into jb-dev

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Geremy Condra 2012-05-30 11:06:54 -07:00 committed by Android (Google) Code Review
commit 03539a36b6
1 changed files with 37 additions and 1 deletions
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38
libc/netbsd/resolv/res_init.c
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@ -99,6 +99,8 @@ __RCSID("$NetBSD: res_init.c,v 1.8 2006/03/19 03:10:08 christos Exp $");
#include <netdb.h>
#ifdef ANDROID_CHANGES
#include <errno.h>
#include <fcntl.h>
#include <sys/system_properties.h>
#endif /* ANDROID_CHANGES */
@ -716,10 +718,44 @@ net_mask(in) /* XXX - should really use system's version of this */
return (htonl(IN_CLASSC_NET));
}
#ifdef ANDROID_CHANGES
static int
real_randomid(u_int *random_value) {
/* open the nonblocking random device, returning -1 on failure */
int random_device = open("/dev/urandom", O_RDONLY);
if (random_device < 0) {
return -1;
}
/* read from the random device, returning -1 on failure (or too many retries)*/
u_int retry = 5;
for (retry; retry > 0; retry--) {
int retval = read(random_device, random_value, sizeof(u_int));
if (retval == sizeof(u_int)) {
*random_value &= 0xffff;
close(random_device);
return 0;
} else if ((retval < 0) && (errno != EINTR)) {
break;
}
}
close(random_device);
return -1;
}
#endif /* ANDROID_CHANGES */
u_int
res_randomid(void) {
#ifdef ANDROID_CHANGES
int status = 0;
u_int output = 0;
status = real_randomid(&output);
if (status != -1) {
return output;
}
#endif /* ANDROID_CHANGES */
struct timeval now;
gettimeofday(&now, NULL);
return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
}