Messages in this thread Patch in this message | | | Date | Wed, 7 Mar 2007 15:12:49 -0800 | From | Chris Wright <> | Subject | [patch 103/101] Fix buffer overflow in Omnikey CardMan 4040 driver (CVE-2007-0005) |
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From: Marcel Holtmann <marcel@holtmann.org>
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> Signed-off-by: Chris Wright <chrisw@sous-sol.org> --- drivers/char/pcmcia/cm4040_cs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- linux-2.6.20.1.orig/drivers/char/pcmcia/cm4040_cs.c +++ linux-2.6.20.1/drivers/char/pcmcia/cm4040_cs.c @@ -273,6 +273,7 @@ static ssize_t cm4040_read(struct file * 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 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; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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