[PATCH 0/4 V2] net: atlantic: more fuzzing fixes

[PATCH 0/4 V2] net: atlantic: more fuzzing fixes

[Grant Grundler]

The Chrome OS fuzzing team posted a "Fuzzing" report for atlantic driver
in Q4 2021 using Chrome OS v5.4 kernel and "Cable Matters
Thunderbolt 3 to 10 Gb Ethernet" (b0 version):
    https://docs.google.com/document/d/e/2PACX-1vT4oCGNhhy_AuUqpu6NGnW0N9HF_jxf2kS7raOpOlNRqJNiTHAtjiHRthXYSeXIRTgfeVvsEt0qK9qK/pub

It essentially describes four problems:
1) validate rxd_wb->next_desc_ptr before populating buff->next
2) "frag[0] not initialized" case in aq_ring_rx_clean()
3) limit iterations handling fragments in aq_ring_rx_clean()
4) validate hw_head_ in hw_atl_b0_hw_ring_tx_head_update()

(1) was fixed by Zekun Shen <bruceshenzk@gmail.com> around the same time with
"atlantic: Fix buff_ring OOB in aq_ring_rx_clean" (SHA1 5f50153288452e10).

I've added one "clean up" contribution:
    "net: atlantic: reduce scope of is_rsc_complete"

I tested the "original" patches using chromeos-v5.4 kernel branch:
    https://chromium-review.googlesource.com/q/hashtag:pcinet-atlantic-2022q1+(status:open%20OR%20status:merged)

I've forward ported those patches to 5.18-rc2 and compiled them but am
unable to test them on 5.18-rc2 kernel (logistics problems).

Credit largely goes to ChromeOS Fuzzing team members:
    Aashay Shringarpure, Yi Chou, Shervin Oloumi

V2 changes:
o drop first patch - was already fixed upstream differently
o reduce (4) "validate hw_head_" to simple bounds checking.

 drivers/net/ethernet/aquantia/atlantic/aq_ring.c        | 17 ++++++++++-------
 .../net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c   |  6 ++++++
 2 files changed, 16 insertions(+), 7 deletions(-)

cheers,
grant

[PATCH 1/4] net: atlantic: fix "frag[0] not initialized"

[Grant Grundler]

In aq_ring_rx_clean(), if buff->is_eop is not set AND
buff->len < AQ_CFG_RX_HDR_SIZE, then hdr_len remains equal to
buff->len and skb_add_rx_frag(xxx, *0*, ...) is not called.

The loop following this code starts calling skb_add_rx_frag() starting
with i=1 and thus frag[0] is never initialized. Since i is initialized
to zero at the top of the primary loop, we can just reference and
post-increment i instead of hardcoding the 0 when calling
skb_add_rx_frag() the first time.

Reported-by: Aashay Shringarpure <aashay@google.com>
Reported-by: Yi Chou <yich@google.com>
Reported-by: Shervin Oloumi <enlightened@google.com>
Signed-off-by: Grant Grundler <grundler@chromium.org>
---
 drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index 77e76c9efd32..440423b0e8ea 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -446,7 +446,7 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 		       ALIGN(hdr_len, sizeof(long)));
 
 		if (buff->len - hdr_len > 0) {
-			skb_add_rx_frag(skb, 0, buff->rxdata.page,
+			skb_add_rx_frag(skb, i++, buff->rxdata.page,
 					buff->rxdata.pg_off + hdr_len,
 					buff->len - hdr_len,
 					AQ_CFG_RX_FRAME_MAX);
@@ -455,7 +455,6 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 
 		if (!buff->is_eop) {
 			buff_ = buff;
-			i = 1U;
 			do {
 				next_ = buff_->next;
 				buff_ = &self->buff_ring[next_];
-- 
2.36.0.512.ge40c2bad7a-goog

[PATCH 2/4] net: atlantic: reduce scope of is_rsc_complete

[Grant Grundler]

Don't defer handling the err case outside the loop. That's pointless.

And since is_rsc_complete is only used inside this loop, declare
it inside the loop to reduce it's scope.

Signed-off-by: Grant Grundler <grundler@chromium.org>
---
 drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index 440423b0e8ea..bc1952131799 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -346,7 +346,6 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 		     int budget)
 {
 	struct net_device *ndev = aq_nic_get_ndev(self->aq_nic);
-	bool is_rsc_completed = true;
 	int err = 0;
 
 	for (; (self->sw_head != self->hw_head) && budget;
@@ -366,6 +365,8 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 		if (!buff->is_eop) {
 			buff_ = buff;
 			do {
+				bool is_rsc_completed = true;
+
 				if (buff_->next >= self->size) {
 					err = -EIO;
 					goto err_exit;
@@ -377,18 +378,16 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 							    next_,
 							    self->hw_head);
 
-				if (unlikely(!is_rsc_completed))
-					break;
+				if (unlikely(!is_rsc_completed)) {
+					err = 0;
+					goto err_exit;
+				}
 
 				buff->is_error |= buff_->is_error;
 				buff->is_cso_err |= buff_->is_cso_err;
 
 			} while (!buff_->is_eop);
 
-			if (!is_rsc_completed) {
-				err = 0;
-				goto err_exit;
-			}
 			if (buff->is_error ||
 			    (buff->is_lro && buff->is_cso_err)) {
 				buff_ = buff;
-- 
2.36.0.512.ge40c2bad7a-goog

[PATCH 3/4] net: atlantic: add check for MAX_SKB_FRAGS

[Grant Grundler]

Enforce that the CPU can not get stuck in an infinite loop.

Reported-by: Aashay Shringarpure <aashay@google.com>
Reported-by: Yi Chou <yich@google.com>
Reported-by: Shervin Oloumi <enlightened@google.com>
Signed-off-by: Grant Grundler <grundler@chromium.org>
---
 drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index bc1952131799..8201ce7adb77 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -363,6 +363,7 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 			continue;
 
 		if (!buff->is_eop) {
+			unsigned int frag_cnt = 0U;
 			buff_ = buff;
 			do {
 				bool is_rsc_completed = true;
@@ -371,6 +372,8 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 					err = -EIO;
 					goto err_exit;
 				}
+
+				frag_cnt++;
 				next_ = buff_->next,
 				buff_ = &self->buff_ring[next_];
 				is_rsc_completed =
@@ -378,7 +381,8 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 							    next_,
 							    self->hw_head);
 
-				if (unlikely(!is_rsc_completed)) {
+				if (unlikely(!is_rsc_completed) ||
+						frag_cnt > MAX_SKB_FRAGS) {
 					err = 0;
 					goto err_exit;
 				}
-- 
2.36.0.512.ge40c2bad7a-goog

[PATCH 4/4] net: atlantic: verify hw_head_ lies within TX buffer ring

[Grant Grundler]

Bounds check hw_head index provided by NIC to verify it lies
within the TX buffer ring.

Reported-by: Aashay Shringarpure <aashay@google.com>
Reported-by: Yi Chou <yich@google.com>
Reported-by: Shervin Oloumi <enlightened@google.com>
Signed-off-by: Grant Grundler <grundler@chromium.org>
---
 drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
index d875ce3ec759..15ede7285fb5 100644
--- a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
+++ b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
@@ -889,6 +889,13 @@ int hw_atl_b0_hw_ring_tx_head_update(struct aq_hw_s *self,
 		err = -ENXIO;
 		goto err_exit;
 	}
+
+	/* Validate that the new hw_head_ is reasonable. */
+	if (hw_head_ >= ring->size) {
+		err = -ENXIO;
+		goto err_exit;
+	}
+
 	ring->hw_head = hw_head_;
 	err = aq_hw_err_from_flags(self);
 
-- 
2.36.0.512.ge40c2bad7a-goog

Re: [PATCH 0/4 V2] net: atlantic: more fuzzing fixes

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Mon,  9 May 2022 19:28:22 -0700 you wrote:
> The Chrome OS fuzzing team posted a "Fuzzing" report for atlantic driver
> in Q4 2021 using Chrome OS v5.4 kernel and "Cable Matters
> Thunderbolt 3 to 10 Gb Ethernet" (b0 version):
>     https://docs.google.com/document/d/e/2PACX-1vT4oCGNhhy_AuUqpu6NGnW0N9HF_jxf2kS7raOpOlNRqJNiTHAtjiHRthXYSeXIRTgfeVvsEt0qK9qK/pub
> 
> It essentially describes four problems:
> 1) validate rxd_wb->next_desc_ptr before populating buff->next
> 2) "frag[0] not initialized" case in aq_ring_rx_clean()
> 3) limit iterations handling fragments in aq_ring_rx_clean()
> 4) validate hw_head_ in hw_atl_b0_hw_ring_tx_head_update()
> 
> [...]

Here is the summary with links:
  - [1/4] net: atlantic: fix "frag[0] not initialized"
    https://git.kernel.org/netdev/net/c/62e0ae0f4020
  - [2/4] net: atlantic: reduce scope of is_rsc_complete
    https://git.kernel.org/netdev/net/c/79784d77ebbd
  - [3/4] net: atlantic: add check for MAX_SKB_FRAGS
    https://git.kernel.org/netdev/net/c/6aecbba12b5c
  - [4/4] net: atlantic: verify hw_head_ lies within TX buffer ring
    https://git.kernel.org/netdev/net/c/2120b7f4d128

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html