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odhcpd: improve odhcpd_urandom() #285

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Merged
openwrt-bot merged 1 commit into from
Oct 22, 2025
Merged

odhcpd: improve odhcpd_urandom() #285

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34 changes: 26 additions & 8 deletions src/odhcpd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -39,12 +39,12 @@
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/syscall.h>
#include <sys/random.h>

#include <libubox/uloop.h>
#include "odhcpd.h"

static int ioctl_sock = -1;
static int urandom_fd = -1;

void __iflog(int lvl, const char *fmt, ...)
{
Expand Down Expand Up @@ -148,13 +148,9 @@ int main(int argc, char **argv)
}

ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);

if (ioctl_sock < 0)
return 4;

if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
return 4;

signal(SIGUSR1, SIG_IGN);
signal(SIGINT, sighandler);
signal(SIGTERM, sighandler);
Expand Down Expand Up @@ -542,11 +538,33 @@ void odhcpd_process(struct odhcpd_event *event)
odhcpd_receive_packets(&event->uloop, 0);
}

int odhcpd_urandom(void *data, size_t len)
void odhcpd_urandom(void *data, size_t len)
{
return read(urandom_fd, data, len);
}
static bool warned_once = false;

while (true) {
ssize_t r;

if (len == 0)
return;

r = getrandom(data, len, GRND_INSECURE);
if (r < 0) {
if (errno == EINTR)
continue;

if (!warned_once) {
error("getrandom(): %m");
warned_once = true;
}

return;
}

len -= r;
data = (uint8_t *)data + r;
}
}

time_t odhcpd_time(void)
{
Expand Down
2 changes: 1 addition & 1 deletion src/odhcpd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -514,7 +514,7 @@ int odhcpd_get_interface_config(const char *ifname, const char *what);
int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6]);
int odhcpd_get_flags(const struct interface *iface);
struct interface* odhcpd_get_interface_by_index(int ifindex);
int odhcpd_urandom(void *data, size_t len);
void odhcpd_urandom(void *data, size_t len);

void odhcpd_run(void);
time_t odhcpd_time(void);
Expand Down