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-rw-r--r--drivers/char/random.c67
1 files changed, 38 insertions, 29 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 46c1b97748b6..0474cac4a84e 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -760,7 +760,7 @@ 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, x;
+ int i;
__u32 data[16], buf[5 + SHA_WORKSPACE_WORDS];
sha_init(buf);
@@ -772,9 +772,11 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
* attempts to find previous ouputs), unless the hash
* function can be inverted.
*/
- for (i = 0, x = 0; i < r->poolinfo->poolwords; i += 16, x+=2) {
- sha_transform(buf, (__u8 *)r->pool+i, buf + 5);
- add_entropy_words(r, &buf[x % 5], 1);
+ for (i = 0; i < r->poolinfo->poolwords; i += 16) {
+ /* hash blocks of 16 words = 512 bits */
+ sha_transform(buf, (__u8 *)(r->pool + i), buf + 5);
+ /* feed back portion of the resulting hash */
+ add_entropy_words(r, &buf[i % 5], 1);
}
/*
@@ -782,7 +784,7 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
* portion of the pool while mixing, and hash one
* final time.
*/
- __add_entropy_words(r, &buf[x % 5], 1, data);
+ __add_entropy_words(r, &buf[i % 5], 1, data);
sha_transform(buf, (__u8 *)data, buf + 5);
/*
@@ -1018,37 +1020,44 @@ random_poll(struct file *file, poll_table * wait)
return mask;
}
-static ssize_t
-random_write(struct file * file, const char __user * buffer,
- size_t count, loff_t *ppos)
+static int
+write_pool(struct entropy_store *r, const char __user *buffer, size_t count)
{
- int ret = 0;
size_t bytes;
__u32 buf[16];
const char __user *p = buffer;
- size_t c = count;
- while (c > 0) {
- bytes = min(c, sizeof(buf));
+ while (count > 0) {
+ bytes = min(count, sizeof(buf));
+ if (copy_from_user(&buf, p, bytes))
+ return -EFAULT;
- bytes -= copy_from_user(&buf, p, bytes);
- if (!bytes) {
- ret = -EFAULT;
- break;
- }
- c -= bytes;
+ count -= bytes;
p += bytes;
- add_entropy_words(&input_pool, buf, (bytes + 3) / 4);
- }
- if (p == buffer) {
- return (ssize_t)ret;
- } else {
- struct inode *inode = file->f_path.dentry->d_inode;
- inode->i_mtime = current_fs_time(inode->i_sb);
- mark_inode_dirty(inode);
- return (ssize_t)(p - buffer);
+ add_entropy_words(r, buf, (bytes + 3) / 4);
}
+
+ return 0;
+}
+
+static ssize_t
+random_write(struct file * file, const char __user * buffer,
+ size_t count, loff_t *ppos)
+{
+ size_t ret;
+ struct inode *inode = file->f_path.dentry->d_inode;
+
+ ret = write_pool(&blocking_pool, buffer, count);
+ if (ret)
+ return ret;
+ ret = write_pool(&nonblocking_pool, buffer, count);
+ if (ret)
+ return ret;
+
+ inode->i_mtime = current_fs_time(inode->i_sb);
+ mark_inode_dirty(inode);
+ return (ssize_t)count;
}
static int
@@ -1087,8 +1096,8 @@ random_ioctl(struct inode * inode, struct file * file,
return -EINVAL;
if (get_user(size, p++))
return -EFAULT;
- retval = random_write(file, (const char __user *) p,
- size, &file->f_pos);
+ retval = write_pool(&input_pool, (const char __user *)p,
+ size);
if (retval < 0)
return retval;
credit_entropy_store(&input_pool, ent_count);