diff options
| author | Marcel Holtmann <marcel@holtmann.org> | 2007-03-11 07:39:14 +0100 |
|---|---|---|
| committer | Adrian Bunk <bunk@stusta.de> | 2007-03-11 07:39:14 +0100 |
| commit | dfe67217aea3eb4ecbab736903f6ecee3458b8a8 (patch) | |
| tree | 4e5e0d69e311e09765dabd2da322faa3b6cb2638 | |
| parent | 59d2b001518d200ba99d213e41c892f5fe750d07 (diff) | |
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: Adrian Bunk <bunk@stusta.de>
| -rw-r--r-- | drivers/char/pcmcia/cm4040_cs.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/char/pcmcia/cm4040_cs.c b/drivers/char/pcmcia/cm4040_cs.c index 744b57d9a589..bab4129171b4 100644 --- a/drivers/char/pcmcia/cm4040_cs.c +++ b/drivers/char/pcmcia/cm4040_cs.c @@ -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; } |