diff options
| author | Jeff Garzik <jeff@garzik.org> | 2006-10-17 00:10:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-17 08:18:49 -0700 |
| commit | 04518bfe8eac2e82b476fb2b0093527adc2bc791 (patch) | |
| tree | 4b90b18cb60d1db94325675886b74f0aa0bf346f /drivers/isdn/i4l | |
| parent | 078d396598401dbaa88d5f95ec45579f9d3dce0e (diff) | |
| download | lwn-04518bfe8eac2e82b476fb2b0093527adc2bc791.tar.gz lwn-04518bfe8eac2e82b476fb2b0093527adc2bc791.zip | |
[PATCH] 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>
Cc: Karsten Keil <kkeil@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/isdn/i4l')
| -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 c3d79eef9e32..69aee2602aa6 100644 --- a/drivers/isdn/i4l/isdn_common.c +++ b/drivers/isdn/i4l/isdn_common.c @@ -1134,9 +1134,12 @@ 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; } |