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[PATCH] powerpc: fix large nvram access

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/dev/nvram uses the user-provided read/write size
for kmalloc, which fails, if a large number is passed.
This will always use a single page at most, which
can be expected to succeed.

Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Arnd Bergmann 2005-12-09 19:21:44 +01:00 committed by Paul Mackerras
parent d52771fce4
commit f9ce299fc6
1 changed files with 50 additions and 56 deletions
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106
arch/powerpc/kernel/nvram_64.c
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@ -80,80 +80,74 @@ static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
static ssize_t dev_nvram_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
ssize_t len;
char *tmp_buffer;
int size;
ssize_t ret;
char *tmp = NULL;
ssize_t size;
if (ppc_md.nvram_size == NULL)
return -ENODEV;
ret = -ENODEV;
if (!ppc_md.nvram_size)
goto out;
ret = 0;
size = ppc_md.nvram_size();
if (*ppos >= size || size < 0)
goto out;
if (!access_ok(VERIFY_WRITE, buf, count))
return -EFAULT;
if (*ppos >= size)
return 0;
if (count > size)
count = size;
count = min_t(size_t, count, size - *ppos);
count = min(count, PAGE_SIZE);
tmp_buffer = (char *) kmalloc(count, GFP_KERNEL);
if (!tmp_buffer) {
printk(KERN_ERR "dev_read_nvram: kmalloc failed\n");
return -ENOMEM;
}
ret = -ENOMEM;
tmp = kmalloc(count, GFP_KERNEL);
if (!tmp)
goto out;
len = ppc_md.nvram_read(tmp_buffer, count, ppos);
if ((long)len <= 0) {
kfree(tmp_buffer);
return len;
}
ret = ppc_md.nvram_read(tmp, count, ppos);
if (ret <= 0)
goto out;
if (copy_to_user(buf, tmp_buffer, len)) {
kfree(tmp_buffer);
return -EFAULT;
}
if (copy_to_user(buf, tmp, ret))
ret = -EFAULT;
kfree(tmp_buffer);
return len;
out:
kfree(tmp);
return ret;
}
static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
size_t count, loff_t *ppos)
{
ssize_t len;
char * tmp_buffer;
int size;
ssize_t ret;
char *tmp = NULL;
ssize_t size;
if (ppc_md.nvram_size == NULL)
return -ENODEV;
ret = -ENODEV;
if (!ppc_md.nvram_size)
goto out;
ret = 0;
size = ppc_md.nvram_size();
if (*ppos >= size || size < 0)
goto out;
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
if (*ppos >= size)
return 0;
if (count > size)
count = size;
count = min_t(size_t, count, size - *ppos);
count = min(count, PAGE_SIZE);
tmp_buffer = (char *) kmalloc(count, GFP_KERNEL);
if (!tmp_buffer) {
printk(KERN_ERR "dev_nvram_write: kmalloc failed\n");
return -ENOMEM;
}
if (copy_from_user(tmp_buffer, buf, count)) {
kfree(tmp_buffer);
return -EFAULT;
}
ret = -ENOMEM;
tmp = kmalloc(count, GFP_KERNEL);
if (!tmp)
goto out;
len = ppc_md.nvram_write(tmp_buffer, count, ppos);
if ((long)len <= 0) {
kfree(tmp_buffer);
return len;
}
ret = -EFAULT;
if (copy_from_user(tmp, buf, count))
goto out;
ret = ppc_md.nvram_write(tmp, count, ppos);
out:
kfree(tmp);
return ret;
kfree(tmp_buffer);
return len;
}
static int dev_nvram_ioctl(struct inode *inode, struct file *file,