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authorMarcel Holtmann <marcel@holtmann.org>2007-03-11 07:39:14 +0100
committerAdrian Bunk <bunk@stusta.de>2007-03-11 07:39:14 +0100
commitdfe67217aea3eb4ecbab736903f6ecee3458b8a8 (patch)
tree4e5e0d69e311e09765dabd2da322faa3b6cb2638 /drivers
parent59d2b001518d200ba99d213e41c892f5fe750d07 (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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/char/pcmcia/cm4040_cs.c3
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;
}