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[PATCH] powerpc: fix large nvram access 

/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
View File

@ -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, static ssize_t dev_nvram_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos) size_t count, loff_t *ppos)
{ {
ssize_t len; ssize_t ret;
char *tmp_buffer; char *tmp = NULL;
int size; ssize_t size;
if (ppc_md.nvram_size == NULL) ret = -ENODEV;
return -ENODEV; if (!ppc_md.nvram_size)
goto out;
ret = 0;
size = ppc_md.nvram_size(); size = ppc_md.nvram_size();
if (*ppos >= size || size < 0)
goto out;
if (!access_ok(VERIFY_WRITE, buf, count)) count = min_t(size_t, count, size - *ppos);
return -EFAULT; count = min(count, PAGE_SIZE);
if (*ppos >= size)
return 0;
if (count > size)
count = size;
tmp_buffer = (char *) kmalloc(count, GFP_KERNEL); ret = -ENOMEM;
if (!tmp_buffer) { tmp = kmalloc(count, GFP_KERNEL);
printk(KERN_ERR "dev_read_nvram: kmalloc failed\n"); if (!tmp)
return -ENOMEM; goto out;
}
len = ppc_md.nvram_read(tmp_buffer, count, ppos); ret = ppc_md.nvram_read(tmp, count, ppos);
if ((long)len <= 0) { if (ret <= 0)
kfree(tmp_buffer); goto out;
return len;
}
if (copy_to_user(buf, tmp_buffer, len)) { if (copy_to_user(buf, tmp, ret))
kfree(tmp_buffer); ret = -EFAULT;
return -EFAULT;
}
kfree(tmp_buffer); out:
return len; kfree(tmp);
return ret;
} }
static ssize_t dev_nvram_write(struct file *file, const char __user *buf, 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; ssize_t ret;
char * tmp_buffer; char *tmp = NULL;
int size; ssize_t size;
if (ppc_md.nvram_size == NULL) ret = -ENODEV;
return -ENODEV; if (!ppc_md.nvram_size)
goto out;
ret = 0;
size = ppc_md.nvram_size(); size = ppc_md.nvram_size();
if (*ppos >= size || size < 0)
goto out;
if (!access_ok(VERIFY_READ, buf, count)) count = min_t(size_t, count, size - *ppos);
return -EFAULT; count = min(count, PAGE_SIZE);
if (*ppos >= size)
return 0;
if (count > size)
count = size;
tmp_buffer = (char *) kmalloc(count, GFP_KERNEL); ret = -ENOMEM;
if (!tmp_buffer) { tmp = kmalloc(count, GFP_KERNEL);
printk(KERN_ERR "dev_nvram_write: kmalloc failed\n"); if (!tmp)
return -ENOMEM; goto out;
}
if (copy_from_user(tmp_buffer, buf, count)) {
kfree(tmp_buffer);
return -EFAULT;
}
len = ppc_md.nvram_write(tmp_buffer, count, ppos); ret = -EFAULT;
if ((long)len <= 0) { if (copy_from_user(tmp, buf, count))
kfree(tmp_buffer); goto out;
return len;
} 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, static int dev_nvram_ioctl(struct inode *inode, struct file *file,