seedrng: do not hash in a constant string, it's not adding entropy

function                                             old     new   delta
seedrng_main                                         906     880     -26
.rodata                                           104899  104873     -26
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-52)             Total: -52 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/miscutils/seedrng.c b/miscutils/seedrng.c
index 4f2441abc..967741dc7 100644
--- a/miscutils/seedrng.c
+++ b/miscutils/seedrng.c
@@ -169,7 +169,7 @@ int seedrng_main(int argc UNUSED_PARAM, char **argv)
         uint8_t new_seed[MAX_SEED_LEN];
         size_t new_seed_len;
         bool new_seed_creditable;
-        struct timespec timestamp;
+        struct timespec timestamp[2];
         sha256_ctx_t hash;
 
         enum {
@@ -197,19 +197,19 @@ int seedrng_main(int argc UNUSED_PARAM, char **argv)
          * Avoid concurrent runs by taking a blocking lock on the directory.
          * Not checking for errors. Looking at manpage,
          * ENOLCK "The kernel ran out of memory for allocating lock records"
-         * seems to be the only one which is likely - and if that happens,
+         * seems to be the only one which is possible - and if that happens,
          * machine is OOMing (much worse problem than inability to lock...).
          * Also, typically configured Linux machines do not fail GFP_KERNEL
          * allocations (they trigger memory reclaim instead).
          */
-        flock(dfd, LOCK_EX); /* would block while another copy runs */
+        flock(dfd, LOCK_EX); /* blocks while another instance runs */
 
         sha256_begin(&hash);
-        sha256_hash(&hash, "SeedRNG v1 Old+New Prefix", 25);
-        clock_gettime(CLOCK_REALTIME, &timestamp);
-        sha256_hash(&hash, &timestamp, sizeof(timestamp));
-        clock_gettime(CLOCK_BOOTTIME, &timestamp);
-        sha256_hash(&hash, &timestamp, sizeof(timestamp));
+//Hashing in a constant string doesn't add any entropy
+//      sha256_hash(&hash, "SeedRNG v1 Old+New Prefix", 25);
+        clock_gettime(CLOCK_REALTIME, &timestamp[0]);
+        clock_gettime(CLOCK_BOOTTIME, &timestamp[1]);
+        sha256_hash(&hash, timestamp, sizeof(timestamp));
 
         for (i = 0; i <= 1; i++) {
                 seed_from_file_if_exists(