diff options
| author | Jeff Garzik <jeff@garzik.org> | 2006-12-18 00:07:43 +0100 |
|---|---|---|
| committer | Adrian Bunk <bunk@stusta.de> | 2006-12-18 00:07:43 +0100 |
| commit | 99146a2190e4606aa6803f5995de885f178ebccd (patch) | |
| tree | 680a9eae9cc94255f4aee183b5ddfdf502a9a113 | |
| parent | 83eda202f1f04d5aa2297998fe44cf6641a03b1d (diff) | |
ISDN: fix drivers, by handling errors thrown by ->readstat()
This is a particularly ugly on-failure bug, possibly security, since the
lack of error handling here is covering up another class of bug: failure to
handle copy_to_user() return values.
The I4L API function ->readstat() returns an integer, and by looking at
several existing driver implementations, it is clear that a negative return
value was meant to indicate an error.
Given that several drivers already return a negative value indicating an
errno-style error, the current code would blindly accept that [negative]
value as a valid amount of bytes read. Obvious damage ensues.
Correcting ->readstat() handling to properly notice errors fixes the
existing code to work correctly on error, and enables future patches to
more easily indicate errors during operation.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
| -rw-r--r-- | drivers/isdn/i4l/isdn_common.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c index 22759c01746a..4cd1a5a0b710 100644 --- a/drivers/isdn/i4l/isdn_common.c +++ b/drivers/isdn/i4l/isdn_common.c @@ -1125,9 +1125,12 @@ isdn_read(struct file *file, char __user *buf, size_t count, loff_t * off) if (dev->drv[drvidx]->interface->readstat) { if (count > dev->drv[drvidx]->stavail) count = dev->drv[drvidx]->stavail; - len = dev->drv[drvidx]->interface-> - readstat(buf, count, drvidx, - isdn_minor2chan(minor)); + len = dev->drv[drvidx]->interface->readstat(buf, count, + drvidx, isdn_minor2chan(minor)); + if (len < 0) { + retval = len; + goto out; + } } else { len = 0; } |