Commit ff05d1c4 authored Jan 23, 2007 by Joel Becker Committed by Mark Fasheh Feb 07, 2007

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>

parent b559292e

fs/configfs/file.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -162,14 +162,17 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size
		int error;

		if (!buffer->page)
		buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
		buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);
		if (!buffer->page)
		return -ENOMEM;

		if (count > PAGE_SIZE)
		count = PAGE_SIZE;
		if (count >= PAGE_SIZE)
		count = PAGE_SIZE - 1;
		error = copy_from_user(buffer->page,buf,count);
		buffer->needs_read_fill = 1;
		/* if buf is assumed to contain a string, terminate it by \0,
		* so e.g. sscanf() can scan the string easily */
		buffer->page[count] = 0;
		return error ? -EFAULT : count;
		}

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