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glib-aux: also use getrandom() for seeding pseudo random generator

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It's worth a try.

Also, drop STATIC_SALT.
This commit is contained in:
Thomas Haller 2021-07-13 16:29:48 +02:00
parent 5eb1b706fc
commit 18597e33cb
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GPG key ID: 29C2366E4DFC5728
1 changed files with 13 additions and 5 deletions
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18
src/libnm-glib-aux/nm-random-utils.c
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@ -30,6 +30,10 @@
#define GRND_NONBLOCK 0x01 #define GRND_NONBLOCK 0x01
#endif #endif
#ifndef GRND_INSECURE
#define GRND_INSECURE 0x04
#endif
#if !HAVE_GETRANDOM && defined(SYS_getrandom) #if !HAVE_GETRANDOM && defined(SYS_getrandom)
static int static int
getrandom(void *buf, size_t buflen, unsigned flags) getrandom(void *buf, size_t buflen, unsigned flags)
@ -42,8 +46,6 @@ getrandom(void *buf, size_t buflen, unsigned flags)
/*****************************************************************************/ /*****************************************************************************/
#define STATIC_SALT "l6z5vMBldDlCD6na"
typedef struct _nm_packed { typedef struct _nm_packed {
uintptr_t heap_ptr; uintptr_t heap_ptr;
uintptr_t stack_ptr; uintptr_t stack_ptr;
@ -54,7 +56,7 @@ typedef struct _nm_packed {
pid_t tid; pid_t tid;
guint32 grand[16]; guint32 grand[16];
guint8 auxval[16]; guint8 auxval[16];
char static_salt[NM_STRLEN(STATIC_SALT)]; guint8 getrandom_buf[20];
} BadRandSeed; } BadRandSeed;
typedef struct _nm_packed { typedef struct _nm_packed {
@ -80,8 +82,6 @@ _bad_random_init_seed(BadRandSeed *seed)
int seed_idx; int seed_idx;
GRand * rand; GRand * rand;
memcpy(seed->static_salt, STATIC_SALT, NM_STRLEN(STATIC_SALT));
/* g_rand_new() reads /dev/urandom, but we already noticed that /* g_rand_new() reads /dev/urandom, but we already noticed that
* /dev/urandom fails to give us good randomness (which is why * /dev/urandom fails to give us good randomness (which is why
* we hit the "bad randomness" code path). So this may not be as * we hit the "bad randomness" code path). So this may not be as
@ -106,6 +106,14 @@ _bad_random_init_seed(BadRandSeed *seed)
memcpy(&seed->auxval, p_at_random, 16); memcpy(&seed->auxval, p_at_random, 16);
} }
#if HAVE_GETRANDOM
/* This is likely to fail, because we already failed a moment earlier. Still, give
* it a try. */
(void) getrandom(seed->getrandom_buf,
sizeof(seed->getrandom_buf),
GRND_INSECURE | GRND_NONBLOCK);
#endif
seed->now_bootime = nm_utils_clock_gettime_nsec(CLOCK_BOOTTIME); seed->now_bootime = nm_utils_clock_gettime_nsec(CLOCK_BOOTTIME);
seed->now_real = g_get_real_time(); seed->now_real = g_get_real_time();
seed->pid = getpid(); seed->pid = getpid();