From: Michael Ellerman mpe@ellerman.id.au
[ Upstream commit d6bce2137f5d6bb1093e96d2f801479099b28094 ]
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 Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/airo.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/airo.c b/drivers/net/wireless/airo.c index 82d24f2b9c190..94df9ddfb7eb1 100644 --- a/drivers/net/wireless/airo.c +++ b/drivers/net/wireless/airo.c @@ -7831,7 +7831,7 @@ 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);