From: Arnd Bergmann Date: Fri, 9 Dec 2005 18:21:44 +0000 (+0100) Subject: [PATCH] powerpc: fix large nvram access X-Git-Tag: v2.6.16-rc1~666^2~56 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=f9ce299fc629d5c899a2e56b00e21f5da05cf590;p=linux-2.6-omap-h63xx.git [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 Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c index c0fcd29918c..fd7db8d542d 100644 --- a/arch/powerpc/kernel/nvram_64.c +++ b/arch/powerpc/kernel/nvram_64.c @@ -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,