From: Jens Axboe axboe@kernel.dk
commit 22b0a222af4df8ee9bb8e07013ab44da9511b047 upstream.
Now that the read side has been converted to fix a regression with splice, convert the write side as well to have some symmetry in the interface used (and help deprecate ->write()).
Signed-off-by: Jens Axboe axboe@kernel.dk [Jason: cleaned up random_ioctl a bit, require full writes in RNDADDENTROPY since it's crediting entropy, simplify control flow of write_pool(), and incorporate suggestions from Al.] Cc: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/random.c | 67 ++++++++++++++++++++++++++------------------------ 1 file changed, 35 insertions(+), 32 deletions(-)
--- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1251,39 +1251,31 @@ static __poll_t random_poll(struct file return crng_ready() ? EPOLLIN | EPOLLRDNORM : EPOLLOUT | EPOLLWRNORM; }
-static int write_pool(const char __user *ubuf, size_t len) +static ssize_t write_pool(struct iov_iter *iter) { - size_t block_len; - int ret = 0; u8 block[BLAKE2S_BLOCK_SIZE]; + ssize_t ret = 0; + size_t copied;
- while (len) { - block_len = min(len, sizeof(block)); - if (copy_from_user(block, ubuf, block_len)) { - ret = -EFAULT; - goto out; - } - len -= block_len; - ubuf += block_len; - mix_pool_bytes(block, block_len); + if (unlikely(!iov_iter_count(iter))) + return 0; + + for (;;) { + copied = copy_from_iter(block, sizeof(block), iter); + ret += copied; + mix_pool_bytes(block, copied); + if (!iov_iter_count(iter) || copied != sizeof(block)) + break; cond_resched(); }
-out: memzero_explicit(block, sizeof(block)); - return ret; + return ret ? ret : -EFAULT; }
-static ssize_t random_write(struct file *file, const char __user *ubuf, - size_t len, loff_t *ppos) +static ssize_t random_write_iter(struct kiocb *kiocb, struct iov_iter *iter) { - int ret; - - ret = write_pool(ubuf, len); - if (ret) - return ret; - - return (ssize_t)len; + return write_pool(iter); }
static ssize_t urandom_read_iter(struct kiocb *kiocb, struct iov_iter *iter) @@ -1315,9 +1307,8 @@ static ssize_t random_read_iter(struct k
static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) { - int size, ent_count; int __user *p = (int __user *)arg; - int retval; + int ent_count;
switch (cmd) { case RNDGETENTCNT: @@ -1334,20 +1325,32 @@ static long random_ioctl(struct file *f, return -EINVAL; credit_init_bits(ent_count); return 0; - case RNDADDENTROPY: + case RNDADDENTROPY: { + struct iov_iter iter; + struct iovec iov; + ssize_t ret; + int len; + if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (get_user(ent_count, p++)) return -EFAULT; if (ent_count < 0) return -EINVAL; - if (get_user(size, p++)) + if (get_user(len, p++)) + return -EFAULT; + ret = import_single_range(WRITE, p, len, &iov, &iter); + if (unlikely(ret)) + return ret; + ret = write_pool(&iter); + if (unlikely(ret < 0)) + return ret; + /* Since we're crediting, enforce that it was all written into the pool. */ + if (unlikely(ret != len)) return -EFAULT; - retval = write_pool((const char __user *)p, size); - if (retval < 0) - return retval; credit_init_bits(ent_count); return 0; + } case RNDZAPENTCNT: case RNDCLEARPOOL: /* No longer has any effect. */ @@ -1373,7 +1376,7 @@ static int random_fasync(int fd, struct
const struct file_operations random_fops = { .read_iter = random_read_iter, - .write = random_write, + .write_iter = random_write_iter, .poll = random_poll, .unlocked_ioctl = random_ioctl, .fasync = random_fasync, @@ -1382,7 +1385,7 @@ const struct file_operations random_fops
const struct file_operations urandom_fops = { .read_iter = urandom_read_iter, - .write = random_write, + .write_iter = random_write_iter, .unlocked_ioctl = random_ioctl, .fasync = random_fasync, .llseek = noop_llseek,