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authorLaurent Bercot <ska-skaware@skarnet.org>2022-04-09 02:28:05 +0000
committerLaurent Bercot <ska@appnovation.com>2022-04-09 02:28:05 +0000
commit4e75b40d8a96c5d51490ddea43566fe8e6d4168c (patch)
tree06358f285c713a7f05297cb7d2826319d6561683 /src/librandom/autosurf.c
parent1fedaae65b56b8548cdf2d8c26e2becece5fec07 (diff)
downloadskalibs-4e75b40d8a96c5d51490ddea43566fe8e6d4168c.tar.xz
Prepare for 2.12.0.0. librandom revamp.
Signed-off-by: Laurent Bercot <ska@appnovation.com>
Diffstat (limited to 'src/librandom/autosurf.c')
-rw-r--r--src/librandom/autosurf.c48
1 files changed, 45 insertions, 3 deletions
diff --git a/src/librandom/autosurf.c b/src/librandom/autosurf.c
index 04a47c2..0a219b8 100644
--- a/src/librandom/autosurf.c
+++ b/src/librandom/autosurf.c
@@ -1,17 +1,59 @@
/* ISC license. */
+#include <unistd.h>
+#include <stdint.h>
+
+#include <skalibs/uint32.h>
+#include <skalibs/tai.h>
+#include <skalibs/sha1.h>
#include <skalibs/random.h>
#include <skalibs/surf.h>
+/*
+ Writes 160 bytes of crap into s.
+ Certainly not cryptographically secure or 100% unpredictable,
+ but we're only using this to seed a fallback internal PRNG.
+*/
+
+static void makeseed (char *s)
+{
+ SHA1Schedule bak = SHA1_INIT() ;
+ {
+ tain now ;
+ char tmp[256] ;
+ uint32_t x = getpid() ;
+ uint32_pack(tmp, x) ; /* if valgrind sends you here, tell it to stfu */
+ x = getppid() ;
+ uint32_pack(tmp + 4, x) ;
+ tain_now(&now) ;
+ tain_pack(tmp + 8, &now) ;
+ sha1_update(&bak, tmp, 8 + TAIN_PACK) ;
+ gethostname(tmp, 256) ;
+ sha1_update(&bak, tmp, 256) ;
+ sha1_final(&bak, tmp) ;
+ sha1_init(&bak) ;
+ sha1_update(&bak, tmp, 20) ;
+ }
+ {
+ char i = 0 ;
+ for (; i < 8 ; i++)
+ {
+ SHA1Schedule ctx = bak ;
+ sha1_update(&ctx, &i, 1) ;
+ sha1_final(&ctx, s + 20*i) ;
+ }
+ }
+}
+
void autosurf (char *s, size_t n)
{
static SURFSchedule ctx = SURFSCHEDULE_ZERO ;
static int need4seed = 1 ;
if (need4seed)
{
- char tmp[160] ;
- random_makeseed(tmp) ;
- surf_init(&ctx, tmp) ;
+ char seed[160] ;
+ makeseed(seed) ;
+ surf_init(&ctx, seed) ;
need4seed = 0 ;
}
surf(&ctx, s, n) ;