From: Chris Wright <chris@wirex.com>
To: Junfeng Yang <yjf@stanford.edu>
Cc: linux-kernel@vger.kernel.org, mc@cs.stanford.edu, kas@fi.muni.cz
Subject: Re: [CHECKER] potential dereference of user pointer errors
Date: Fri, 21 Mar 2003 15:55:47 -0800 [thread overview]
Message-ID: <20030321155547.C646@figure1.int.wirex.com> (raw)
In-Reply-To: <Pine.GSO.4.44.0303202226230.24869-100000@elaine24.Stanford.EDU>; from yjf@stanford.edu on Thu, Mar 20, 2003 at 10:33:45PM -0800
* Junfeng Yang (yjf@stanford.edu) wrote:
>
> [BUG] cosa_getidstr calls copy_to_user on arg, which implies arg is
> tainted.
True, arg is a pointer from userspace call to ioctl().
> /home/junfeng/linux-2.5.63/drivers/net/wan/cosa.c:1109:cosa_readmem:
> ERROR:TAINTED deferencing "d" tainted by [dist=2][called by
> cosa_ioctl_common:parm3 calling cosa_getidstr:parm1 calling
> copy_to_user:parm0]
Both cosa_readmem and cosa_download don't seem to do any validation of
the user supplied ptr at all before dereferncing it in get_user. And
it'd make sense to use 'code' in cosa_reamdme (as in cosa_download)
instead of 'd->code'. Jan, does this look OK?
thanks,
-chris
--
Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net
===== drivers/net/wan/cosa.c 1.17 vs edited =====
--- 1.17/drivers/net/wan/cosa.c Mon Jan 13 17:11:59 2003
+++ edited/drivers/net/wan/cosa.c Fri Mar 21 15:53:38 2003
@@ -1057,7 +1057,8 @@
return -EPERM;
}
- if (get_user(addr, &(d->addr)) ||
+ if (verify_area(VERIFY_READ, d, sizeof(*d)) ||
+ __get_user(addr, &(d->addr)) ||
__get_user(len, &(d->len)) ||
__get_user(code, &(d->code)))
return -EFAULT;
@@ -1098,7 +1099,8 @@
return -EPERM;
}
- if (get_user(addr, &(d->addr)) ||
+ if (verify_area(VERIFY_READ, d, sizeof(*d)) ||
+ __get_user(addr, &(d->addr)) ||
__get_user(len, &(d->len)) ||
__get_user(code, &(d->code)))
return -EFAULT;
@@ -1106,7 +1108,7 @@
/* If something fails, force the user to reset the card */
cosa->firmware_status &= ~COSA_FW_RESET;
- if ((i=readmem(cosa, d->code, len, addr)) < 0) {
+ if ((i=readmem(cosa, code, len, addr)) < 0) {
printk(KERN_NOTICE "cosa%d: reading memory failed: %d\n",
cosa->num, i);
return -EIO;
next prev parent reply other threads:[~2003-03-21 23:46 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-04 11:12 [CHECKER] potential races in kernel/*.c mm/*.c net/*ipv4*.c Dawson Engler
2003-03-04 12:24 ` Hugh Dickins
2003-03-04 13:23 ` Martin Josefsson
2003-03-21 6:33 ` [CHECKER] potential dereference of user pointer errors Junfeng Yang
2003-03-21 21:44 ` Chris Wright
2003-03-21 21:58 ` Junfeng Yang
2003-03-21 22:06 ` Chris Wright
2003-03-21 22:08 ` Junfeng Yang
2003-03-21 22:15 ` Chris Wright
2003-03-22 20:49 ` Alan Cox
2003-03-22 20:19 ` Chris Wright
2003-03-21 23:55 ` Chris Wright [this message]
2003-03-27 8:07 ` Jan Kasprzak
2003-03-27 17:10 ` Chris Wright
2003-04-21 7:49 ` [CHECKER] Help Needed! Junfeng Yang
2003-04-21 21:26 ` Chris Wright
2003-04-26 2:18 ` [CHECKER] 30 potential dereference of user-pointer errors Junfeng Yang
2003-04-27 9:26 ` James Morris
2003-04-28 1:55 ` Junfeng Yang
2003-04-27 20:18 ` Nick Holloway
2003-04-27 21:14 ` Junfeng Yang
2003-04-27 21:29 ` Junfeng Yang
2003-04-28 6:43 ` [CHECKER] 3 potential user-pointer errors in drivers/usb/serial that can print out arbitrary kernel data Junfeng Yang
2003-04-29 7:25 ` Greg KH
2003-04-29 9:14 ` Junfeng Yang
2003-04-28 6:50 ` [CHECKER] 8 potential user-pointer errors that allow arbitrary writes to kernel Junfeng Yang
2003-04-28 12:49 ` Alan Cox
2003-04-28 19:11 ` Junfeng Yang
2003-04-29 0:02 ` [CHECKER] 5 potential user-pointer errors in write_proc Junfeng Yang
2003-04-29 7:26 ` [CHECKER] 30 potential dereference of user-pointer errors Greg KH
2003-03-22 0:15 ` [CHECKER] potential dereference of user pointer errors Chris Wright
2003-03-22 0:32 ` Greg KH
2003-03-22 0:47 ` Chris Wright
2003-03-22 1:00 ` Greg KH
2003-03-22 0:32 ` Chris Wright
2003-03-23 23:10 ` Junfeng Yang
2003-03-24 0:24 ` [CHECKER] 63 potential calling blocking functions with locks held errors Junfeng Yang
2003-03-24 12:35 ` [CHECKER] 8 potential calling blocking kmalloc(GFP_KERNEL) " Junfeng Yang
2003-03-24 0:29 ` [CHECKER] 1 potential double unlock error Junfeng Yang
2003-03-24 9:07 ` [CHECKER] potential dereference of user pointer errors Jaroslav Kysela
2003-03-24 22:28 ` Raja R Harinath
2003-03-25 0:44 ` David S. Miller
2003-03-25 18:52 ` Raja R Harinath
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