| Message ID | 20190827003326.147452-1-drinkcat@chromium.org (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | [RFC] ath10k: Fix skb->len (properly) in ath10k_sdio_mbox_rx_packet | expand |
> -----Original Message----- > From: ath10k <ath10k-bounces@lists.infradead.org> On Behalf Of Nicolas > Boichat > Sent: Tuesday, August 27, 2019 8:33 AM > To: kvalo@codeaurora.org > Cc: Alagu Sankar <alagusankar@silex-india.com>; netdev@vger.kernel.org; > briannorris@chromium.org; linux-wireless@vger.kernel.org; linux- > kernel@vger.kernel.org; ath10k@lists.infradead.org; > wgong@codeaurora.org; niklas.cassel@linaro.org; tientzu@chromium.org; > David S . Miller <davem@davemloft.net> > Subject: [EXT] [PATCH, RFC] ath10k: Fix skb->len (properly) in > ath10k_sdio_mbox_rx_packet > > (not a formal patch, take this as a bug report for now, I can clean > up depending on the feedback I get here) > > There's at least 3 issues here, and the patch fixes 2/3 only, I'm not sure > how/if 1 should be handled. > 1. ath10k_sdio_mbox_rx_alloc allocating skb of a incorrect size (too > small) > 2. ath10k_sdio_mbox_rx_packet calling skb_put with that incorrect size. > 3. ath10k_sdio_mbox_rx_process_packet attempts to fixup the size, but > does not use proper skb_put commands to do so, so we end up with > a mismatch between skb->head + skb->tail and skb->data + skb->len. > > Let's start with 3, this is quite serious as this and causes corruptions > in the TCP stack, as the stack tries to coalesce packets, and relies on > skb->tail being correct (that is, skb_tail_pointer must point to the > first byte _after_ the data): one must never manipulate skb->len > directly. > > Instead, we need to use skb_put to allocate more space (which updates > skb->len and skb->tail). But it seems odd to do that in > ath10k_sdio_mbox_rx_process_packet, so I move the code to > ath10k_sdio_mbox_rx_packet (point 2 above). > > However, there is still something strange (point 1 above), why is > ath10k_sdio_mbox_rx_alloc allocating packets of the incorrect > (too small?) size? What happens if the packet is bigger than alloc_len? > Does this lead to corruption/lost data? > > Fixes: 8530b4e7b22bc3b ("ath10k: sdio: set skb len for all rx packets") > Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> > > --- > > One simple way to test this is this scriplet, that sends a lot of > small packets over SSH: > (for i in `seq 1 300`; do echo $i; sleep 0.1; done) | ssh $IP cat > > In my testing it rarely ever reach 300 without failure. > > drivers/net/wireless/ath/ath10k/sdio.c | 18 ++++++++++++------ > 1 file changed, 12 insertions(+), 6 deletions(-) > > diff --git a/drivers/net/wireless/ath/ath10k/sdio.c > b/drivers/net/wireless/ath/ath10k/sdio.c > index 8ed4fbd8d6c3888..a9f5002863ee7bb 100644 > --- a/drivers/net/wireless/ath/ath10k/sdio.c > +++ b/drivers/net/wireless/ath/ath10k/sdio.c > @@ -381,16 +381,14 @@ static int > ath10k_sdio_mbox_rx_process_packet(struct ath10k *ar, > struct ath10k_htc_hdr *htc_hdr = (struct ath10k_htc_hdr *)skb->data; > bool trailer_present = htc_hdr->flags & > ATH10K_HTC_FLAG_TRAILER_PRESENT; > enum ath10k_htc_ep_id eid; > - u16 payload_len; > u8 *trailer; > int ret; > > - payload_len = le16_to_cpu(htc_hdr->len); > - skb->len = payload_len + sizeof(struct ath10k_htc_hdr); > + /* TODO: Remove this? */ If the pkt->act_len has set again in ath10k_sdio_mbox_rx_packet, seems not needed. > + WARN_ON(skb->len != le16_to_cpu(htc_hdr->len) + sizeof(*htc_hdr)); > > if (trailer_present) { > - trailer = skb->data + sizeof(*htc_hdr) + > - payload_len - htc_hdr->trailer_len; > + trailer = skb->data + skb->len - htc_hdr->trailer_len; > > eid = pipe_id_to_eid(htc_hdr->eid); > > @@ -637,8 +635,16 @@ static int ath10k_sdio_mbox_rx_packet(struct > ath10k *ar, > ret = ath10k_sdio_readsb(ar, ar_sdio->mbox_info.htc_addr, > skb->data, pkt->alloc_len); > pkt->status = ret; > - if (!ret) > + if (!ret) { > + /* Update actual length. */ > + /* FIXME: This looks quite wrong, why is pkt->act_len not > + * correct in the first place? > + */ Firmware will do bundle for rx packet, and the aligned length by block size(256) of each packet's len is same in a bundle. Eg. packet 1 len: 300, aligned length:512 packet 2 len: 400, aligned length:512 packet 3 len: 200, aligned length:256 packet 4 len: 100, aligned length:256 packet 5 len: 700, aligned length:768 packet 6 len: 600, aligned length:768 then packet 1,2 will in bundle 1, packet 3,4 in a bundle 2, packet 5,6 in a bundle 3. For bundle 1, packet 1,2 will both allocate with len 512, and act_len is 300 first, then packet 2's len will be overwrite to 400. For bundle 2, packet 3,4 will both allocate with len 256, and act_len is 200 first, then packet 4's len will be overwrite to 100. For bundle 3, packet 5,6 will both allocate with len 768, and act_len is 700 first, then packet 6's len will be overwrite to 600. > + struct ath10k_htc_hdr *htc_hdr = > + (struct ath10k_htc_hdr *)skb->data; > + pkt->act_len = le16_to_cpu(htc_hdr->len) + sizeof(*htc_hdr); > skb_put(skb, pkt->act_len); > + } > > return ret; > } > -- > 2.23.0.187.g17f5b7556c-goog > > > _______________________________________________ > ath10k mailing list > ath10k@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/ath10k
On Tue, Aug 27, 2019 at 11:34 AM Wen Gong <wgong@qti.qualcomm.com> wrote: > > > -----Original Message----- > > From: ath10k <ath10k-bounces@lists.infradead.org> On Behalf Of Nicolas > > Boichat > > Sent: Tuesday, August 27, 2019 8:33 AM > > To: kvalo@codeaurora.org > > Cc: Alagu Sankar <alagusankar@silex-india.com>; netdev@vger.kernel.org; > > briannorris@chromium.org; linux-wireless@vger.kernel.org; linux- > > kernel@vger.kernel.org; ath10k@lists.infradead.org; > > wgong@codeaurora.org; niklas.cassel@linaro.org; tientzu@chromium.org; > > David S . Miller <davem@davemloft.net> > > Subject: [EXT] [PATCH, RFC] ath10k: Fix skb->len (properly) in > > ath10k_sdio_mbox_rx_packet > > > > (not a formal patch, take this as a bug report for now, I can clean > > up depending on the feedback I get here) > > > > There's at least 3 issues here, and the patch fixes 2/3 only, I'm not sure > > how/if 1 should be handled. > > 1. ath10k_sdio_mbox_rx_alloc allocating skb of a incorrect size (too > > small) > > 2. ath10k_sdio_mbox_rx_packet calling skb_put with that incorrect size. > > 3. ath10k_sdio_mbox_rx_process_packet attempts to fixup the size, but > > does not use proper skb_put commands to do so, so we end up with > > a mismatch between skb->head + skb->tail and skb->data + skb->len. > > > > Let's start with 3, this is quite serious as this and causes corruptions > > in the TCP stack, as the stack tries to coalesce packets, and relies on > > skb->tail being correct (that is, skb_tail_pointer must point to the > > first byte _after_ the data): one must never manipulate skb->len > > directly. > > > > Instead, we need to use skb_put to allocate more space (which updates > > skb->len and skb->tail). But it seems odd to do that in > > ath10k_sdio_mbox_rx_process_packet, so I move the code to > > ath10k_sdio_mbox_rx_packet (point 2 above). > > > > However, there is still something strange (point 1 above), why is > > ath10k_sdio_mbox_rx_alloc allocating packets of the incorrect > > (too small?) size? What happens if the packet is bigger than alloc_len? > > Does this lead to corruption/lost data? > > > > Fixes: 8530b4e7b22bc3b ("ath10k: sdio: set skb len for all rx packets") > > Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> > > > > --- > > > > One simple way to test this is this scriplet, that sends a lot of > > small packets over SSH: > > (for i in `seq 1 300`; do echo $i; sleep 0.1; done) | ssh $IP cat > > > > In my testing it rarely ever reach 300 without failure. > > > > drivers/net/wireless/ath/ath10k/sdio.c | 18 ++++++++++++------ > > 1 file changed, 12 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/net/wireless/ath/ath10k/sdio.c > > b/drivers/net/wireless/ath/ath10k/sdio.c > > index 8ed4fbd8d6c3888..a9f5002863ee7bb 100644 > > --- a/drivers/net/wireless/ath/ath10k/sdio.c > > +++ b/drivers/net/wireless/ath/ath10k/sdio.c > > @@ -381,16 +381,14 @@ static int > > ath10k_sdio_mbox_rx_process_packet(struct ath10k *ar, > > struct ath10k_htc_hdr *htc_hdr = (struct ath10k_htc_hdr *)skb->data; > > bool trailer_present = htc_hdr->flags & > > ATH10K_HTC_FLAG_TRAILER_PRESENT; > > enum ath10k_htc_ep_id eid; > > - u16 payload_len; > > u8 *trailer; > > int ret; > > > > - payload_len = le16_to_cpu(htc_hdr->len); > > - skb->len = payload_len + sizeof(struct ath10k_htc_hdr); > > + /* TODO: Remove this? */ > If the pkt->act_len has set again in ath10k_sdio_mbox_rx_packet, seems not needed. Sure, will drop. > > + WARN_ON(skb->len != le16_to_cpu(htc_hdr->len) + sizeof(*htc_hdr)); > > > > if (trailer_present) { > > - trailer = skb->data + sizeof(*htc_hdr) + > > - payload_len - htc_hdr->trailer_len; > > + trailer = skb->data + skb->len - htc_hdr->trailer_len; > > > > eid = pipe_id_to_eid(htc_hdr->eid); > > > > @@ -637,8 +635,16 @@ static int ath10k_sdio_mbox_rx_packet(struct > > ath10k *ar, > > ret = ath10k_sdio_readsb(ar, ar_sdio->mbox_info.htc_addr, > > skb->data, pkt->alloc_len); > > pkt->status = ret; > > - if (!ret) > > + if (!ret) { > > + /* Update actual length. */ > > + /* FIXME: This looks quite wrong, why is pkt->act_len not > > + * correct in the first place? > > + */ > Firmware will do bundle for rx packet, and the aligned length by block size(256) of each packet's len is same > in a bundle. > > Eg. > packet 1 len: 300, aligned length:512 > packet 2 len: 400, aligned length:512 > packet 3 len: 200, aligned length:256 > packet 4 len: 100, aligned length:256 > packet 5 len: 700, aligned length:768 > packet 6 len: 600, aligned length:768 > > then packet 1,2 will in bundle 1, packet 3,4 in a bundle 2, packet 5,6 in a bundle 3. > > For bundle 1, packet 1,2 will both allocate with len 512, and act_len is 300 first, > then packet 2's len will be overwrite to 400. > > For bundle 2, packet 3,4 will both allocate with len 256, and act_len is 200 first, > then packet 4's len will be overwrite to 100. > > For bundle 3, packet 5,6 will both allocate with len 768, and act_len is 700 first, > then packet 6's len will be overwrite to 600. Ok thanks, I'll send a v2 with an improved description. > > + struct ath10k_htc_hdr *htc_hdr = > > + (struct ath10k_htc_hdr *)skb->data; > > + pkt->act_len = le16_to_cpu(htc_hdr->len) + sizeof(*htc_hdr); > > skb_put(skb, pkt->act_len); > > + } > > > > return ret; > > } > > -- > > 2.23.0.187.g17f5b7556c-goog > > > > > > _______________________________________________ > > ath10k mailing list > > ath10k@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/ath10k
diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c index 8ed4fbd8d6c3888..a9f5002863ee7bb 100644 --- a/drivers/net/wireless/ath/ath10k/sdio.c +++ b/drivers/net/wireless/ath/ath10k/sdio.c @@ -381,16 +381,14 @@ static int ath10k_sdio_mbox_rx_process_packet(struct ath10k *ar, struct ath10k_htc_hdr *htc_hdr = (struct ath10k_htc_hdr *)skb->data; bool trailer_present = htc_hdr->flags & ATH10K_HTC_FLAG_TRAILER_PRESENT; enum ath10k_htc_ep_id eid; - u16 payload_len; u8 *trailer; int ret; - payload_len = le16_to_cpu(htc_hdr->len); - skb->len = payload_len + sizeof(struct ath10k_htc_hdr); + /* TODO: Remove this? */ + WARN_ON(skb->len != le16_to_cpu(htc_hdr->len) + sizeof(*htc_hdr)); if (trailer_present) { - trailer = skb->data + sizeof(*htc_hdr) + - payload_len - htc_hdr->trailer_len; + trailer = skb->data + skb->len - htc_hdr->trailer_len; eid = pipe_id_to_eid(htc_hdr->eid); @@ -637,8 +635,16 @@ static int ath10k_sdio_mbox_rx_packet(struct ath10k *ar, ret = ath10k_sdio_readsb(ar, ar_sdio->mbox_info.htc_addr, skb->data, pkt->alloc_len); pkt->status = ret; - if (!ret) + if (!ret) { + /* Update actual length. */ + /* FIXME: This looks quite wrong, why is pkt->act_len not + * correct in the first place? + */ + struct ath10k_htc_hdr *htc_hdr = + (struct ath10k_htc_hdr *)skb->data; + pkt->act_len = le16_to_cpu(htc_hdr->len) + sizeof(*htc_hdr); skb_put(skb, pkt->act_len); + } return ret; }
(not a formal patch, take this as a bug report for now, I can clean up depending on the feedback I get here) There's at least 3 issues here, and the patch fixes 2/3 only, I'm not sure how/if 1 should be handled. 1. ath10k_sdio_mbox_rx_alloc allocating skb of a incorrect size (too small) 2. ath10k_sdio_mbox_rx_packet calling skb_put with that incorrect size. 3. ath10k_sdio_mbox_rx_process_packet attempts to fixup the size, but does not use proper skb_put commands to do so, so we end up with a mismatch between skb->head + skb->tail and skb->data + skb->len. Let's start with 3, this is quite serious as this and causes corruptions in the TCP stack, as the stack tries to coalesce packets, and relies on skb->tail being correct (that is, skb_tail_pointer must point to the first byte _after_ the data): one must never manipulate skb->len directly. Instead, we need to use skb_put to allocate more space (which updates skb->len and skb->tail). But it seems odd to do that in ath10k_sdio_mbox_rx_process_packet, so I move the code to ath10k_sdio_mbox_rx_packet (point 2 above). However, there is still something strange (point 1 above), why is ath10k_sdio_mbox_rx_alloc allocating packets of the incorrect (too small?) size? What happens if the packet is bigger than alloc_len? Does this lead to corruption/lost data? Fixes: 8530b4e7b22bc3b ("ath10k: sdio: set skb len for all rx packets") Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> --- One simple way to test this is this scriplet, that sends a lot of small packets over SSH: (for i in `seq 1 300`; do echo $i; sleep 0.1; done) | ssh $IP cat In my testing it rarely ever reach 300 without failure. drivers/net/wireless/ath/ath10k/sdio.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)