configfs: Zero terminate data in configfs attribute writes.
Attributes in configfs are text files. As such, most handlers expect to be able to call functions like simple_strtoul() without checking the bounds of the buffer. Change the call to zero terminate the buffer before calling the client's ->store() method. This does reduce the attribute size from PAGE_SIZE to PAGE_SIZE-1. Also, change get_zeroed_page() to alloc_page(), as we are handling the termination. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
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@ -162,14 +162,17 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size
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int error;
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if (!buffer->page)
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buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
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buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);
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if (!buffer->page)
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return -ENOMEM;
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if (count > PAGE_SIZE)
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count = PAGE_SIZE;
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if (count >= PAGE_SIZE)
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count = PAGE_SIZE - 1;
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error = copy_from_user(buffer->page,buf,count);
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buffer->needs_read_fill = 1;
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/* if buf is assumed to contain a string, terminate it by \0,
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* so e.g. sscanf() can scan the string easily */
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buffer->page[count] = 0;
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return error ? -EFAULT : count;
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}
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