| Message ID | 20200122040728.8437-2-mpe@ellerman.id.au (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | [1/2] airo: Fix possible info leak in AIROOLDIOCTL/SIOCDEVPRIVATE | expand |
From: Michael Ellerman <mpe@ellerman.id.au> Date: Wed, 22 Jan 2020 15:07:28 +1100 > The driver for Cisco Aironet 4500 and 4800 series cards (airo.c), > implements AIROOLDIOCTL/SIOCDEVPRIVATE in airo_ioctl(). > > The ioctl handler copies an aironet_ioctl struct from userspace, which > includes a command. Some of the commands are handled in readrids(), > where the user controlled command is converted into a driver-internal > value called "ridcode". > > There are two command values, AIROGWEPKTMP and AIROGWEPKNV, which > correspond to ridcode values of RID_WEP_TEMP and RID_WEP_PERM > respectively. These commands both have checks that the user has > CAP_NET_ADMIN, with the comment that "Only super-user can read WEP > keys", otherwise they return -EPERM. > > However there is another command value, AIRORRID, that lets the user > specify the ridcode value directly, with no other checks. This means > the user can bypass the CAP_NET_ADMIN check on AIROGWEPKTMP and > AIROGWEPKNV. > > Fix it by moving the CAP_NET_ADMIN check out of the command handling > and instead do it later based on the ridcode. That way regardless of > whether the ridcode is set via AIROGWEPKTMP or AIROGWEPKNV, or passed > in using AIRORID, we always do the CAP_NET_ADMIN check. > > Found by Ilja by code inspection, not tested as I don't have the > required hardware. > > Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Applied and queued up for -stable.
diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c index d69c2ee7e206..c4c8f1b62e1e 100644 --- a/drivers/net/wireless/cisco/airo.c +++ b/drivers/net/wireless/cisco/airo.c @@ -7790,16 +7790,8 @@ static int readrids(struct net_device *dev, aironet_ioctl *comp) { case AIROGVLIST: ridcode = RID_APLIST; break; case AIROGDRVNAM: ridcode = RID_DRVNAME; break; case AIROGEHTENC: ridcode = RID_ETHERENCAP; break; - case AIROGWEPKTMP: ridcode = RID_WEP_TEMP; - /* Only super-user can read WEP keys */ - if (!capable(CAP_NET_ADMIN)) - return -EPERM; - break; - case AIROGWEPKNV: ridcode = RID_WEP_PERM; - /* Only super-user can read WEP keys */ - if (!capable(CAP_NET_ADMIN)) - return -EPERM; - break; + case AIROGWEPKTMP: ridcode = RID_WEP_TEMP; break; + case AIROGWEPKNV: ridcode = RID_WEP_PERM; break; case AIROGSTAT: ridcode = RID_STATUS; break; case AIROGSTATSD32: ridcode = RID_STATSDELTA; break; case AIROGSTATSC32: ridcode = RID_STATS; break; @@ -7813,6 +7805,12 @@ static int readrids(struct net_device *dev, aironet_ioctl *comp) { return -EINVAL; } + if (ridcode == RID_WEP_TEMP || ridcode == RID_WEP_PERM) { + /* Only super-user can read WEP keys */ + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + } + if ((iobuf = kzalloc(RIDSIZE, GFP_KERNEL)) == NULL) return -ENOMEM;
The driver for Cisco Aironet 4500 and 4800 series cards (airo.c), implements AIROOLDIOCTL/SIOCDEVPRIVATE in airo_ioctl(). The ioctl handler copies an aironet_ioctl struct from userspace, which includes a command. Some of the commands are handled in readrids(), where the user controlled command is converted into a driver-internal value called "ridcode". There are two command values, AIROGWEPKTMP and AIROGWEPKNV, which correspond to ridcode values of RID_WEP_TEMP and RID_WEP_PERM respectively. These commands both have checks that the user has CAP_NET_ADMIN, with the comment that "Only super-user can read WEP keys", otherwise they return -EPERM. However there is another command value, AIRORRID, that lets the user specify the ridcode value directly, with no other checks. This means the user can bypass the CAP_NET_ADMIN check on AIROGWEPKTMP and AIROGWEPKNV. Fix it by moving the CAP_NET_ADMIN check out of the command handling and instead do it later based on the ridcode. That way regardless of whether the ridcode is set via AIROGWEPKTMP or AIROGWEPKNV, or passed in using AIRORID, we always do the CAP_NET_ADMIN check. Found by Ilja by code inspection, not tested as I don't have the required hardware. Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- drivers/net/wireless/cisco/airo.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)