[PATCH 2/7] random: cleanup integer types

From: Jason A. Donenfeld
Date: Thu Jan 13 2022 - 10:44:48 EST


Rather than using the userspace type, __uXX, switch to using uXX. And
rather than using variously chosen `char *` or `unsigned char *`, use
`u8 *` uniformly for things that aren't strings, in the case where we
are doing byte-by-byte traversal.

Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
---
drivers/char/random.c | 95 +++++++++++++++++++++----------------------
1 file changed, 47 insertions(+), 48 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index c8f05b7551dc..4b84b95428bc 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -456,7 +456,7 @@ static DEFINE_SPINLOCK(random_ready_list_lock);
static LIST_HEAD(random_ready_list);

struct crng_state {
- __u32 state[16];
+ u32 state[16];
unsigned long init_time;
spinlock_t lock;
};
@@ -483,9 +483,9 @@ static bool crng_need_final_init = false;
static int crng_init_cnt = 0;
static unsigned long crng_global_init_time = 0;
#define CRNG_INIT_CNT_THRESH (2*CHACHA_KEY_SIZE)
-static void _extract_crng(struct crng_state *crng, __u8 out[CHACHA_BLOCK_SIZE]);
+static void _extract_crng(struct crng_state *crng, u8 out[CHACHA_BLOCK_SIZE]);
static void _crng_backtrack_protect(struct crng_state *crng,
- __u8 tmp[CHACHA_BLOCK_SIZE], int used);
+ u8 tmp[CHACHA_BLOCK_SIZE], int used);
static void process_random_ready_list(void);
static void _get_random_bytes(void *buf, int nbytes);

@@ -509,7 +509,7 @@ MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression");
struct entropy_store;
struct entropy_store {
/* read-only data: */
- __u32 *pool;
+ u32 *pool;
const char *name;

/* read-write data: */
@@ -518,7 +518,7 @@ struct entropy_store {
unsigned short input_rotate;
int entropy_count;
unsigned int last_data_init:1;
- __u8 last_data[EXTRACT_SIZE];
+ u8 last_data[EXTRACT_SIZE];
};

static ssize_t extract_entropy(struct entropy_store *r, void *buf,
@@ -527,7 +527,7 @@ static ssize_t _extract_entropy(struct entropy_store *r, void *buf,
size_t nbytes, int fips);

static void crng_reseed(struct crng_state *crng, struct entropy_store *r);
-static __u32 input_pool_data[INPUT_POOL_WORDS] __latent_entropy;
+static u32 input_pool_data[INPUT_POOL_WORDS] __latent_entropy;

static struct entropy_store input_pool = {
.name = "input",
@@ -535,7 +535,7 @@ static struct entropy_store input_pool = {
.pool = input_pool_data
};

-static __u32 const twist_table[8] = {
+static u32 const twist_table[8] = {
0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };

@@ -554,8 +554,8 @@ static void _mix_pool_bytes(struct entropy_store *r, const void *in,
{
unsigned long i;
int input_rotate;
- const unsigned char *bytes = in;
- __u32 w;
+ const u8 *bytes = in;
+ u32 w;

input_rotate = r->input_rotate;
i = r->add_ptr;
@@ -608,10 +608,10 @@ static void mix_pool_bytes(struct entropy_store *r, const void *in,
}

struct fast_pool {
- __u32 pool[4];
+ u32 pool[4];
unsigned long last;
- unsigned short reg_idx;
- unsigned char count;
+ u16 reg_idx;
+ u8 count;
};

/*
@@ -621,8 +621,8 @@ struct fast_pool {
*/
static void fast_mix(struct fast_pool *f)
{
- __u32 a = f->pool[0], b = f->pool[1];
- __u32 c = f->pool[2], d = f->pool[3];
+ u32 a = f->pool[0], b = f->pool[1];
+ u32 c = f->pool[2], d = f->pool[3];

a += b; c += d;
b = rol32(b, 6); d = rol32(d, 27);
@@ -814,14 +814,14 @@ static bool __init crng_init_try_arch_early(struct crng_state *crng)
static void crng_initialize_secondary(struct crng_state *crng)
{
chacha_init_consts(crng->state);
- _get_random_bytes(&crng->state[4], sizeof(__u32) * 12);
+ _get_random_bytes(&crng->state[4], sizeof(u32) * 12);
crng_init_try_arch(crng);
crng->init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
}

static void __init crng_initialize_primary(struct crng_state *crng)
{
- _extract_entropy(&input_pool, &crng->state[4], sizeof(__u32) * 12, 0);
+ _extract_entropy(&input_pool, &crng->state[4], sizeof(u32) * 12, 0);
if (crng_init_try_arch_early(crng) && trust_cpu && crng_init < 2) {
invalidate_batched_entropy();
numa_crng_init();
@@ -911,10 +911,10 @@ static struct crng_state *select_crng(void)
* path. So we can't afford to dilly-dally. Returns the number of
* bytes processed from cp.
*/
-static size_t crng_fast_load(const char *cp, size_t len)
+static size_t crng_fast_load(const u8 *cp, size_t len)
{
unsigned long flags;
- char *p;
+ u8 *p;
size_t ret = 0;

if (!spin_trylock_irqsave(&primary_crng.lock, flags))
@@ -923,7 +923,7 @@ static size_t crng_fast_load(const char *cp, size_t len)
spin_unlock_irqrestore(&primary_crng.lock, flags);
return 0;
}
- p = (unsigned char *) &primary_crng.state[4];
+ p = (u8 *) &primary_crng.state[4];
while (len > 0 && crng_init_cnt < CRNG_INIT_CNT_THRESH) {
p[crng_init_cnt % CHACHA_KEY_SIZE] ^= *cp;
cp++; crng_init_cnt++; len--; ret++;
@@ -951,14 +951,14 @@ static size_t crng_fast_load(const char *cp, size_t len)
* like a fixed DMI table (for example), which might very well be
* unique to the machine, but is otherwise unvarying.
*/
-static int crng_slow_load(const char *cp, size_t len)
+static int crng_slow_load(const u8 *cp, size_t len)
{
unsigned long flags;
- static unsigned char lfsr = 1;
- unsigned char tmp;
+ static u8 lfsr = 1;
+ u8 tmp;
unsigned i, max = CHACHA_KEY_SIZE;
- const char * src_buf = cp;
- char * dest_buf = (char *) &primary_crng.state[4];
+ const u8 * src_buf = cp;
+ u8 * dest_buf = (u8 *) &primary_crng.state[4];

if (!spin_trylock_irqsave(&primary_crng.lock, flags))
return 0;
@@ -987,8 +987,8 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
unsigned long flags;
int i, num;
union {
- __u8 block[CHACHA_BLOCK_SIZE];
- __u32 key[8];
+ u8 block[CHACHA_BLOCK_SIZE];
+ u32 key[8];
} buf;

if (r) {
@@ -1015,7 +1015,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
}

static void _extract_crng(struct crng_state *crng,
- __u8 out[CHACHA_BLOCK_SIZE])
+ u8 out[CHACHA_BLOCK_SIZE])
{
unsigned long flags, init_time;

@@ -1033,7 +1033,7 @@ static void _extract_crng(struct crng_state *crng,
spin_unlock_irqrestore(&crng->lock, flags);
}

-static void extract_crng(__u8 out[CHACHA_BLOCK_SIZE])
+static void extract_crng(u8 out[CHACHA_BLOCK_SIZE])
{
_extract_crng(select_crng(), out);
}
@@ -1043,26 +1043,26 @@ static void extract_crng(__u8 out[CHACHA_BLOCK_SIZE])
* enough) to mutate the CRNG key to provide backtracking protection.
*/
static void _crng_backtrack_protect(struct crng_state *crng,
- __u8 tmp[CHACHA_BLOCK_SIZE], int used)
+ u8 tmp[CHACHA_BLOCK_SIZE], int used)
{
unsigned long flags;
- __u32 *s, *d;
+ u32 *s, *d;
int i;

- used = round_up(used, sizeof(__u32));
+ used = round_up(used, sizeof(u32));
if (used + CHACHA_KEY_SIZE > CHACHA_BLOCK_SIZE) {
extract_crng(tmp);
used = 0;
}
spin_lock_irqsave(&crng->lock, flags);
- s = (__u32 *) &tmp[used];
+ s = (u32 *) &tmp[used];
d = &crng->state[4];
for (i=0; i < 8; i++)
*d++ ^= *s++;
spin_unlock_irqrestore(&crng->lock, flags);
}

-static void crng_backtrack_protect(__u8 tmp[CHACHA_BLOCK_SIZE], int used)
+static void crng_backtrack_protect(u8 tmp[CHACHA_BLOCK_SIZE], int used)
{
_crng_backtrack_protect(select_crng(), tmp, used);
}
@@ -1070,7 +1070,7 @@ static void crng_backtrack_protect(__u8 tmp[CHACHA_BLOCK_SIZE], int used)
static ssize_t extract_crng_user(void __user *buf, size_t nbytes)
{
ssize_t ret = 0, i = CHACHA_BLOCK_SIZE;
- __u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4);
+ u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4);
int large_request = (nbytes > 256);

while (nbytes) {
@@ -1241,15 +1241,15 @@ static void add_interrupt_bench(cycles_t start)
#define add_interrupt_bench(x)
#endif

-static __u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
+static u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
{
- __u32 *ptr = (__u32 *) regs;
+ u32 *ptr = (u32 *) regs;
unsigned int idx;

if (regs == NULL)
return 0;
idx = READ_ONCE(f->reg_idx);
- if (idx >= sizeof(struct pt_regs) / sizeof(__u32))
+ if (idx >= sizeof(struct pt_regs) / sizeof(u32))
idx = 0;
ptr += idx++;
WRITE_ONCE(f->reg_idx, idx);
@@ -1263,8 +1263,8 @@ void add_interrupt_randomness(int irq)
struct pt_regs *regs = get_irq_regs();
unsigned long now = jiffies;
cycles_t cycles = random_get_entropy();
- __u32 c_high, j_high;
- __u64 ip;
+ u32 c_high, j_high;
+ u64 ip;

if (cycles == 0)
cycles = get_reg(fast_pool, regs);
@@ -1282,8 +1282,7 @@ void add_interrupt_randomness(int irq)

if (unlikely(crng_init == 0)) {
if ((fast_pool->count >= 64) &&
- crng_fast_load((char *) fast_pool->pool,
- sizeof(fast_pool->pool)) > 0) {
+ crng_fast_load((u8 *)fast_pool->pool, sizeof(fast_pool->pool)) > 0) {
fast_pool->count = 0;
fast_pool->last = now;
}
@@ -1380,7 +1379,7 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
*
* Note: we assume that .poolwords is a multiple of 16 words.
*/
-static void extract_buf(struct entropy_store *r, __u8 *out)
+static void extract_buf(struct entropy_store *r, u8 *out)
{
struct blake2s_state state __aligned(__alignof__(unsigned long));
u8 hash[BLAKE2S_HASH_SIZE];
@@ -1430,7 +1429,7 @@ static ssize_t _extract_entropy(struct entropy_store *r, void *buf,
size_t nbytes, int fips)
{
ssize_t ret = 0, i;
- __u8 tmp[EXTRACT_SIZE];
+ u8 tmp[EXTRACT_SIZE];
unsigned long flags;

while (nbytes) {
@@ -1468,7 +1467,7 @@ static ssize_t _extract_entropy(struct entropy_store *r, void *buf,
static ssize_t extract_entropy(struct entropy_store *r, void *buf,
size_t nbytes, int min, int reserved)
{
- __u8 tmp[EXTRACT_SIZE];
+ u8 tmp[EXTRACT_SIZE];
unsigned long flags;

/* if last_data isn't primed, we need EXTRACT_SIZE extra bytes */
@@ -1530,7 +1529,7 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller,
*/
static void _get_random_bytes(void *buf, int nbytes)
{
- __u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4);
+ u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4);

trace_get_random_bytes(nbytes, _RET_IP_);

@@ -1724,7 +1723,7 @@ EXPORT_SYMBOL(del_random_ready_callback);
int __must_check get_random_bytes_arch(void *buf, int nbytes)
{
int left = nbytes;
- char *p = buf;
+ u8 *p = buf;

trace_get_random_bytes_arch(left, _RET_IP_);
while (left) {
@@ -1866,7 +1865,7 @@ static int
write_pool(struct entropy_store *r, const char __user *buffer, size_t count)
{
size_t bytes;
- __u32 t, buf[16];
+ u32 t, buf[16];
const char __user *p = buffer;

while (count > 0) {
@@ -1876,7 +1875,7 @@ write_pool(struct entropy_store *r, const char __user *buffer, size_t count)
if (copy_from_user(&buf, p, bytes))
return -EFAULT;

- for (b = bytes ; b > 0 ; b -= sizeof(__u32), i++) {
+ for (b = bytes; b > 0; b -= sizeof(u32), i++) {
if (!arch_get_random_int(&t))
break;
buf[i] ^= t;
--
2.34.1