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systemd/SOURCES/0656-random-seed-make-the-l...

80 lines
2.7 KiB

From b16d2d2da2d84552cfe7437d728ab8d65bacb03c Mon Sep 17 00:00:00 2001
From: Franck Bui <fbui@suse.com>
Date: Thu, 20 Oct 2022 08:45:02 +0200
Subject: [PATCH] random-seed: make the logic to calculate the number of bytes
read from the random seed file clearer
We want the size to lie within [/proc/sys/kernel/random/poolsize,RANDOM_POOL_SIZE_MAX]
interval. Let's make it more obvious.
Also move the logic in a dedicated function.
(cherry picked from commit 205138d88abf2e087440803ee046128092b722c6)
Related: RHEL-16952
---
src/random-seed/random-seed.c | 29 +++++++++++++++++++----------
1 file changed, 19 insertions(+), 10 deletions(-)
diff --git a/src/random-seed/random-seed.c b/src/random-seed/random-seed.c
index 2ca2181ddb..5b5629d817 100644
--- a/src/random-seed/random-seed.c
+++ b/src/random-seed/random-seed.c
@@ -115,6 +115,22 @@ static CreditEntropy may_credit(int seed_fd) {
return CREDIT_ENTROPY_NO_WAY;
}
+static int random_seed_size(int seed_fd, size_t *ret_size) {
+ struct stat st;
+
+ assert(ret_size);
+ assert(seed_fd >= 0);
+
+ if (fstat(seed_fd, &st) < 0)
+ return log_error_errno(errno, "Failed to stat() seed file " RANDOM_SEED ": %m");
+
+ /* If the seed file is larger than what the kernel expects, then honour the existing size and
+ * save/restore as much as it says */
+
+ *ret_size = CLAMP((uint64_t)st.st_size, random_pool_size(), RANDOM_POOL_SIZE_MAX);
+ return 0;
+}
+
static int help(int argc, char *argv[], void *userdata) {
_cleanup_free_ char *link = NULL;
int r;
@@ -193,7 +209,6 @@ static int run(int argc, char *argv[]) {
_cleanup_free_ void* buf = NULL;
struct sha256_ctx hash_state;
size_t buf_size;
- struct stat st;
ssize_t k, l;
int r;
@@ -205,8 +220,6 @@ static int run(int argc, char *argv[]) {
umask(0022);
- buf_size = random_pool_size();
-
r = mkdir_parents(RANDOM_SEED, 0755);
if (r < 0)
return log_error_errno(r, "Failed to create directory " RANDOM_SEED_DIR ": %m");
@@ -261,13 +274,9 @@ static int run(int argc, char *argv[]) {
assert_not_reached();
}
- if (fstat(seed_fd, &st) < 0)
- return log_error_errno(errno, "Failed to stat() seed file " RANDOM_SEED ": %m");
-
- /* If the seed file is larger than what we expect, then honour the existing size and save/restore as
- * much as it says */
- if ((uint64_t) st.st_size > buf_size)
- buf_size = MIN(st.st_size, RANDOM_POOL_SIZE_MAX);
+ r = random_seed_size(seed_fd, &buf_size);
+ if (r < 0)
+ return r;
buf = malloc(buf_size);
if (!buf)