Re: [PATCH for-4.1] brcmfmac: avoid null pointer access when brcmf_msgbuf_get_pktid() fails

[Arend van Spriel <arend@broadcom.com>]

On 05/26/15 13:19, Arend van Spriel wrote:
> The function brcmf_msgbuf_get_pktid() may return a NULL pointer so
> the callers should check the return pointer before accessing it to
> avoid the crash below (see [1]):
>
> brcmfmac: brcmf_msgbuf_get_pktid: Invalid packet id 273 (not in use)
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
> IP: [<ffffffff8145b225>] skb_pull+0x5/0x50
> PGD 0
> Oops: 0000 [#1] PREEMPT SMP
> Modules linked in: pci_stub vboxpci(O) vboxnetflt(O) vboxnetadp(O) vboxdrv(O)
>   snd_hda_codec_hdmi bnep mousedev hid_generic ushwmon msr ext4 crc16 mbcache
>   jbd2 sd_mod uas usb_storage ahci libahci libata scsi_mod xhci_pci xhci_hcd
>   usbcore usb_common
> CPU: 0 PID: 1661 Comm: irq/61-brcmf_pc Tainted: G O    4.0.1-MacbookPro-ARCH #1
> Hardware name: Apple Inc. MacBookPro12,1/Mac-E43C1C25D4880AD6,
>   BIOS MBP121.88Z.0167.B02.1503241251 03/24/2015
> task: ffff880264203cc0 ti: ffff88025ffe4000 task.ti: ffff88025ffe4000
> RIP: 0010:[<ffffffff8145b225>]  [<ffffffff8145b225>] skb_pull+0x5/0x50
> RSP: 0018:ffff88025ffe7d40  EFLAGS: 00010202
> RAX: 0000000000000000 RBX: ffff88008a33c000 RCX: 0000000000000044
> RDX: 0000000000000000 RSI: 000000000000004a RDI: 0000000000000000
> RBP: ffff88025ffe7da8 R08: 0000000000000096 R09: 000000000000004a
> R10: 0000000000000000 R11: 000000000000048e R12: ffff88025ff14f00
> R13: 0000000000000000 R14: ffff880263b48200 R15: ffff88008a33c000
> FS:  0000000000000000(0000) GS:ffff88026ec00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000080 CR3: 000000000180b000 CR4: 00000000003407f0
> Stack:
>   ffffffffa06aed74 ffff88025ffe7dc8 ffff880263b48270 ffff880263b48278
>   05ea88020000004a 0002ffff81014635 000000001720b2f6 ffff88026ec116c0
>   ffff880263b48200 0000000000010000 ffff880263b4ae00 ffff880264203cc0
> Call Trace:
>   [<ffffffffa06aed74>] ? brcmf_msgbuf_process_rx+0x404/0x480 [brcmfmac]
>   [<ffffffff810cea60>] ? irq_finalize_oneshot.part.30+0xf0/0xf0
>   [<ffffffffa06afb55>] brcmf_proto_msgbuf_rx_trigger+0x35/0xf0 [brcmfmac]
>   [<ffffffffa06baf2a>] brcmf_pcie_isr_thread_v2+0x8a/0x130 [brcmfmac]
>   [<ffffffff810cea80>] irq_thread_fn+0x20/0x50
>   [<ffffffff810ceddf>] irq_thread+0x13f/0x170
>   [<ffffffff810cebf0>] ? wake_threads_waitq+0x30/0x30
>   [<ffffffff810ceca0>] ? irq_thread_dtor+0xb0/0xb0
>   [<ffffffff81092a08>] kthread+0xd8/0xf0
>   [<ffffffff81092930>] ? kthread_create_on_node+0x1c0/0x1c0
>   [<ffffffff8156d898>] ret_from_fork+0x58/0x90
>   [<ffffffff81092930>] ? kthread_create_on_node+0x1c0/0x1c0
> Code: 01 83 e2 f7 88 50 01 48 83 c4 08 5b 5d f3 c3 0f 1f 80 00 00 00 00 83 e2
>   f7 88 50 01 c3 66 0f 1f 84 00 00 00 00 00 0f 1f
> RIP  [<ffffffff8145b225>] skb_pull+0x5/0x50
>   RSP<ffff88025ffe7d40>
> CR2: 0000000000000080
> ---[ end trace b074c0f90e7c997d ]---
>
> [1] http://mid.gmane.org/20150430193259.GA5630@googlemail.com
>
> Cc:<stable@vger.kernel.org>  # v3.18, v3.19, v4.0, v4.1
> Reported-by: Michael Hornung<mhornung.linux@gmail.com>
> Reviewed-by: Hante Meuleman<meuleman@broadcom.com>
> Reviewed-by: Pieter-Paul Giesberts<pieterpg@broadcom.com>
> Signed-off-by: Arend van Spriel<arend@broadcom.com>

> Change-Id: Ia82879e6acc3c768133e80de391a6a5cf9799b17
> Reviewed-on: http://hnd-swgit.sj.broadcom.com:8080/3281

Sorry, Kalle

These should not have been here. Oh well.

Regards,
Arend

> ---
>   drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c | 12 +++++-------
>   1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c b/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c
> index 4ec9811..65efb14 100644
> --- a/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c
> +++ b/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c
> @@ -511,11 +511,9 @@ static int brcmf_msgbuf_query_dcmd(struct brcmf_pub *drvr, int ifidx,
>   				     msgbuf->rx_pktids,
>   				     msgbuf->ioctl_resp_pktid);
>   	if (msgbuf->ioctl_resp_ret_len != 0) {
> -		if (!skb) {
> -			brcmf_err("Invalid packet id idx recv'd %d\n",
> -				  msgbuf->ioctl_resp_pktid);
> +		if (!skb)
>   			return -EBADF;
> -		}
> +
>   		memcpy(buf, skb->data, (len<  msgbuf->ioctl_resp_ret_len) ?
>   				       len : msgbuf->ioctl_resp_ret_len);
>   	}
> @@ -874,10 +872,8 @@ brcmf_msgbuf_process_txstatus(struct brcmf_msgbuf *msgbuf, void *buf)
>   	flowid -= BRCMF_NROF_H2D_COMMON_MSGRINGS;
>   	skb = brcmf_msgbuf_get_pktid(msgbuf->drvr->bus_if->dev,
>   				     msgbuf->tx_pktids, idx);
> -	if (!skb) {
> -		brcmf_err("Invalid packet id idx recv'd %d\n", idx);
> +	if (!skb)
>   		return;
> -	}
>
>   	set_bit(flowid, msgbuf->txstatus_done_map);
>   	commonring = msgbuf->flowrings[flowid];
> @@ -1156,6 +1152,8 @@ brcmf_msgbuf_process_rx_complete(struct brcmf_msgbuf *msgbuf, void *buf)
>
>   	skb = brcmf_msgbuf_get_pktid(msgbuf->drvr->bus_if->dev,
>   				     msgbuf->rx_pktids, idx);
> +	if (!skb)
> +		return;
>
>   	if (data_offset)
>   		skb_pull(skb, data_offset);