Messages in this thread Patch in this message | | | From | Paul Gortmaker <> | Subject | [34-longterm 131/209] Fix pktcdvd ioctl dev_minor range check | Date | Thu, 14 Apr 2011 13:54:49 -0400 |
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From: Dan Rosenberg <drosenberg@vsecurity.com>
===================================================================== | This is a commit scheduled for the next v2.6.34 longterm release. | | If you see a problem with using this for longterm, please comment.| =====================================================================
commit 252a52aa4fa22a668f019e55b3aac3ff71ec1c29 upstream
The PKT_CTRL_CMD_STATUS device ioctl retrieves a pointer to a pktcdvd_device from the global pkt_devs array. The index into this array is provided directly by the user and is a signed integer, so the comparison to ensure that it falls within the bounds of this array will fail when provided with a negative index.
This can be used to read arbitrary kernel memory or cause a crash due to an invalid pointer dereference. This can be exploited by users with permission to open /dev/pktcdvd/control (on many distributions, this is readable by group "cdrom").
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com> [ Rather than add a cast, just make the function take the right type -Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- drivers/block/pktcdvd.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index 8a549db..8403fd5 100644 --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -2368,7 +2368,7 @@ static void pkt_release_dev(struct pktcdvd_device *pd, int flush) pkt_shrink_pktlist(pd); } -static struct pktcdvd_device *pkt_find_dev_from_minor(int dev_minor) +static struct pktcdvd_device *pkt_find_dev_from_minor(unsigned int dev_minor) { if (dev_minor >= MAX_WRITERS) return NULL; -- 1.7.4.4
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