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seedrng: manually inline seed_rng

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We can now remove a separate buffer

function                                             old     new   delta
seedrng_main                                         930     884     -46

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Bernhard Reutner-Fischer 2022-05-01 17:01:14 +02:00 committed by Denys Vlasenko
parent 54867fec12
commit a157c4c978
1 changed files with 15 additions and 21 deletions
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36
util-linux/seedrng.c
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@ -112,31 +112,16 @@ static bool read_new_seed(uint8_t *seed, size_t len)
return is_creditable;
}
static void seed_rng(uint8_t *seed, size_t len, bool credit)
static void seed_from_file_if_exists(const char *filename, int dfd, bool credit, sha256_ctx_t *hash)
{
struct {
int entropy_count;
int buf_size;
uint8_t buffer[MAX_SEED_LEN];
uint8_t buf[MAX_SEED_LEN];
} req;
int random_fd;
req.entropy_count = credit ? len * 8 : 0;
req.buf_size = len;
memcpy(req.buffer, seed, len);
random_fd = xopen("/dev/urandom", O_RDONLY);
xioctl(random_fd, RNDADDENTROPY, &req);
if (ENABLE_FEATURE_CLEAN_UP)
close(random_fd);
}
static void seed_from_file_if_exists(const char *filename, int dfd, bool credit, sha256_ctx_t *hash)
{
uint8_t seed[MAX_SEED_LEN];
ssize_t seed_len;
seed_len = open_read_close(filename, seed, sizeof(seed));
seed_len = open_read_close(filename, req.buf, sizeof(req.buf));
if (seed_len < 0) {
if (errno != ENOENT)
bb_perror_msg_and_die("can't read '%s'", filename);
@ -144,6 +129,8 @@ static void seed_from_file_if_exists(const char *filename, int dfd, bool credit,
}
xunlink(filename);
if (seed_len != 0) {
int fd;
/* We are going to use this data to seed the RNG:
* we believe it to genuinely containing entropy.
* If this just-unlinked file survives
@ -156,10 +143,17 @@ static void seed_from_file_if_exists(const char *filename, int dfd, bool credit,
//Length is not random, and taking its address spills variable to stack
// sha256_hash(hash, &seed_len, sizeof(seed_len));
sha256_hash(hash, seed, seed_len);
sha256_hash(hash, req.buf, seed_len);
req.buf_size = seed_len;
seed_len *= 8;
req.entropy_count = credit ? seed_len : 0;
printf("Seeding %u bits %s crediting\n",
(unsigned)seed_len * 8, credit ? "and" : "without");
seed_rng(seed, seed_len, credit);
(unsigned)seed_len, credit ? "and" : "without");
fd = xopen("/dev/urandom", O_RDONLY);
xioctl(fd, RNDADDENTROPY, &req);
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
}
}