From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     linux-kernel@vger.kernel.org, tytso@mit.edu
Cc:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH 2/7] random: cleanup integer types
Date:   Thu, 13 Jan 2022 16:44:08 +0100
Message-Id: <20220113154413.29513-3-Jason@zx2c4.com>
In-Reply-To: <20220113154413.29513-1-Jason@zx2c4.com>
References: <20220113154413.29513-1-Jason@zx2c4.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@zx2c4.com>
---
 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