From: Arend van Spriel Date: Tue, 26 May 2015 13:19:46 +0200 Subject: [PATCH] brcmfmac: avoid null pointer access when brcmf_msgbuf_get_pktid() fails 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: [] 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:[] [] 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: [] ? brcmf_msgbuf_process_rx+0x404/0x480 [brcmfmac] [] ? irq_finalize_oneshot.part.30+0xf0/0xf0 [] brcmf_proto_msgbuf_rx_trigger+0x35/0xf0 [brcmfmac] [] brcmf_pcie_isr_thread_v2+0x8a/0x130 [brcmfmac] [] irq_thread_fn+0x20/0x50 [] irq_thread+0x13f/0x170 [] ? wake_threads_waitq+0x30/0x30 [] ? irq_thread_dtor+0xb0/0xb0 [] kthread+0xd8/0xf0 [] ? kthread_create_on_node+0x1c0/0x1c0 [] ret_from_fork+0x58/0x90 [] ? 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 [] skb_pull+0x5/0x50 RSP CR2: 0000000000000080 ---[ end trace b074c0f90e7c997d ]--- [1] http://mid.gmane.org/20150430193259.GA5630@googlemail.com Cc: # v3.18, v3.19, v4.0, v4.1 Reported-by: Michael Hornung Reviewed-by: Hante Meuleman Reviewed-by: Pieter-Paul Giesberts Signed-off-by: Arend van Spriel --- --- a/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c +++ b/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c @@ -500,11 +500,9 @@ static int brcmf_msgbuf_query_dcmd(struc 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); } @@ -866,10 +864,8 @@ brcmf_msgbuf_process_txstatus(struct brc 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]; @@ -1148,6 +1144,8 @@ brcmf_msgbuf_process_rx_complete(struct 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);