From: Dan Rosenberg Date: Mon, 27 Sep 2010 16:30:28 +0000 (-0400) Subject: Fix pktcdvd ioctl dev_minor range check X-Git-Tag: v2.6.36-rc6~8 X-Git-Url: https://bbs.cooldavid.org/git/?a=commitdiff_plain;h=252a52aa4fa22a668f019e55b3aac3ff71ec1c29;hp=95929eff2cb01e9858779283795f4e3943ee020d;p=net-next-2.6.git Fix pktcdvd ioctl dev_minor range check 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 [ Rather than add a cast, just make the function take the right type -Linus ] Signed-off-by: Linus Torvalds --- diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index b1cbeb59bb7..37a2bb59507 100644 --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -2369,7 +2369,7 @@ 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;