From: Michael Ellerman <mpe@ellerman.id.au>
To: netdev@vger.kernel.org
Cc: linux-wireless@vger.kernel.org, kvalo@codeaurora.org,
davem@davemloft.net, linux-kernel@vger.kernel.org,
security@kernel.org, ivansprundel@ioactive.com
Subject: [PATCH 1/2] airo: Fix possible info leak in AIROOLDIOCTL/SIOCDEVPRIVATE
Date: Wed, 22 Jan 2020 15:07:27 +1100 [thread overview]
Message-ID: <20200122040728.8437-1-mpe@ellerman.id.au> (raw)
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 and a length. Some of the commands are handled in
readrids(), which kmalloc()'s a buffer of RIDSIZE (2048) bytes.
That buffer is then passed to PC4500_readrid(), which has two cases.
The else case does some setup and then reads up to RIDSIZE bytes from
the hardware into the kmalloc()'ed buffer.
Here len == RIDSIZE, pBuf is the kmalloc()'ed buffer:
// read the rid length field
bap_read(ai, pBuf, 2, BAP1);
// length for remaining part of rid
len = min(len, (int)le16_to_cpu(*(__le16*)pBuf)) - 2;
...
// read remainder of the rid
rc = bap_read(ai, ((__le16*)pBuf)+1, len, BAP1);
PC4500_readrid() then returns to readrids() which does:
len = comp->len;
if (copy_to_user(comp->data, iobuf, min(len, (int)RIDSIZE))) {
Where comp->len is the user controlled length field.
So if the "rid length field" returned by the hardware is < 2048, and
the user requests 2048 bytes in comp->len, we will leak the previous
contents of the kmalloc()'ed buffer to userspace.
Fix it by kzalloc()'ing the buffer.
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 | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
index f43c06569ea1..d69c2ee7e206 100644
--- a/drivers/net/wireless/cisco/airo.c
+++ b/drivers/net/wireless/cisco/airo.c
@@ -7813,7 +7813,7 @@ static int readrids(struct net_device *dev, aironet_ioctl *comp) {
return -EINVAL;
}
- if ((iobuf = kmalloc(RIDSIZE, GFP_KERNEL)) == NULL)
+ if ((iobuf = kzalloc(RIDSIZE, GFP_KERNEL)) == NULL)
return -ENOMEM;
PC4500_readrid(ai,ridcode,iobuf,RIDSIZE, 1);
--
2.21.1
next reply other threads:[~2020-01-22 4:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 4:07 Michael Ellerman [this message]
2020-01-22 4:07 ` [PATCH 2/2] airo: Add missing CAP_NET_ADMIN check in AIROOLDIOCTL/SIOCDEVPRIVATE Michael Ellerman
2020-01-23 10:03 ` David Miller
2020-01-23 10:03 ` [PATCH 1/2] airo: Fix possible info leak " David Miller
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