Commit 059819a4 authored Mar 06, 2007 by Marcel Holtmann Committed by Linus Torvalds Mar 06, 2007

[PATCH] Fix buffer overflow in Omnikey CardMan 4040 driver (CVE-2007-0005)



Based on a patch from Don Howard <dhoward@redhat.com>

When calling write() with a buffer larger than 512 bytes, the
driver's write buffer overflows, allowing to overwrite the EIP and
execute arbitrary code with kernel privileges.

In read(), there exists a similar problem, but coming from the device.
A malicous or buggy device sending more than 512 bytes can overflow
of the driver's read buffer, with the same effects as above.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 266d4f40

drivers/char/pcmcia/cm4040_cs.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -273,6 +273,7 @@ static ssize_t cm4040_read(struct file filp, char __user buf,
		DEBUGP(6, dev, "BytesToRead=%lu\n", bytes_to_read);

		min_bytes_to_read = min(count, bytes_to_read + 5);
		min_bytes_to_read = min_t(size_t, min_bytes_to_read, READ_WRITE_BUFFER_SIZE);

		DEBUGP(6, dev, "Min=%lu\n", min_bytes_to_read);

		@@ -340,7 +341,7 @@ static ssize_t cm4040_write(struct file filp, const char __user buf,
		return 0;
		}

		if (count < 5) {
		if ((count < 5) \|\| (count > READ_WRITE_BUFFER_SIZE)) {
		DEBUGP(2, dev, "<- cm4040_write buffersize=%Zd < 5\n", count);
		return -EIO;
		}