diff options
| -rw-r--r-- | drivers/char/random.c | 37 |
1 files changed, 19 insertions, 18 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index ba0d70305384..d33f52cd437b 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -439,7 +439,7 @@ static struct entropy_store nonblocking_pool = { }; /* - * This function adds a byte into the entropy "pool". It does not + * This function adds bytes into the entropy "pool". It does not * update the entropy estimate. The caller should call * credit_entropy_store if this is appropriate. * @@ -448,8 +448,8 @@ static struct entropy_store nonblocking_pool = { * it's cheap to do so and helps slightly in the expected case where * the entropy is concentrated in the low-order bits. */ -static void __add_entropy_words(struct entropy_store *r, const __u32 *in, - int nwords, __u32 out[16]) +static void mix_pool_bytes_extract(struct entropy_store *r, const void *in, + int nbytes, __u8 out[64]) { static __u32 const twist_table[8] = { 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, @@ -457,6 +457,7 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, unsigned long i, j, tap1, tap2, tap3, tap4, tap5; int input_rotate; int wordmask = r->poolinfo->poolwords - 1; + const char *bytes = in; __u32 w; unsigned long flags; @@ -471,8 +472,9 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, input_rotate = r->input_rotate; i = r->add_ptr; - while (nwords--) { - w = rol32(*in++, input_rotate & 31); + /* mix one byte at a time to simplify size handling and churn faster */ + while (nbytes--) { + w = rol32(*bytes++, input_rotate & 31); i = (i - 1) & wordmask; /* XOR in the various taps */ @@ -500,15 +502,14 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, if (out) for (j = 0; j < 16; j++) - out[j] = r->pool[(i - j) & wordmask]; + ((__u32 *)out)[j] = r->pool[(i - j) & wordmask]; spin_unlock_irqrestore(&r->lock, flags); } -static inline void add_entropy_words(struct entropy_store *r, const __u32 *in, - int nwords) +static void mix_pool_bytes(struct entropy_store *r, const void *in, int bytes) { - __add_entropy_words(r, in, nwords, NULL); + mix_pool_bytes_extract(r, in, bytes, NULL); } /* @@ -584,7 +585,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num) sample.jiffies = jiffies; sample.cycles = get_cycles(); sample.num = num; - add_entropy_words(&input_pool, (u32 *)&sample, sizeof(sample)/4); + mix_pool_bytes(&input_pool, &sample, sizeof(sample)); /* * Calculate number of bits of randomness we probably added. @@ -700,7 +701,7 @@ static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes) bytes = extract_entropy(r->pull, tmp, bytes, random_read_wakeup_thresh / 8, rsvd); - add_entropy_words(r, tmp, (bytes + 3) / 4); + mix_pool_bytes(r, tmp, bytes); credit_entropy_store(r, bytes*8); } } @@ -758,7 +759,8 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, static void extract_buf(struct entropy_store *r, __u8 *out) { int i; - __u32 extract[16], hash[5], workspace[SHA_WORKSPACE_WORDS]; + __u32 hash[5], workspace[SHA_WORKSPACE_WORDS]; + __u8 extract[64]; /* Generate a hash across the pool, 16 words (512 bits) at a time */ sha_init(hash); @@ -774,13 +776,13 @@ static void extract_buf(struct entropy_store *r, __u8 *out) * brute-forcing the feedback as hard as brute-forcing the * hash. */ - __add_entropy_words(r, hash, 5, extract); + mix_pool_bytes_extract(r, hash, sizeof(hash), extract); /* * To avoid duplicates, we atomically extract a portion of the * pool while mixing, and hash one final time. */ - sha_transform(hash, (__u8 *)extract, workspace); + sha_transform(hash, extract, workspace); memset(extract, 0, sizeof(extract)); memset(workspace, 0, sizeof(workspace)); @@ -887,9 +889,8 @@ static void init_std_data(struct entropy_store *r) spin_unlock_irqrestore(&r->lock, flags); now = ktime_get_real(); - add_entropy_words(r, (__u32 *)&now, sizeof(now)/4); - add_entropy_words(r, (__u32 *)utsname(), - sizeof(*(utsname()))/4); + mix_pool_bytes(r, &now, sizeof(now)); + mix_pool_bytes(r, utsname(), sizeof(*(utsname()))); } static int rand_initialize(void) @@ -1030,7 +1031,7 @@ write_pool(struct entropy_store *r, const char __user *buffer, size_t count) count -= bytes; p += bytes; - add_entropy_words(r, buf, (bytes + 3) / 4); + mix_pool_bytes(r, buf, bytes); cond_resched(); } |