[SRU][F][PATCH 1/1] net: atlantic: eliminate double free in error handling logic

[Massimiliano Pellizzer]

From: Igor Russkikh <irusskikh at marvell.com>

Driver has a logic leak in ring data allocation/free,
where aq_ring_free could be called multiple times on same ring,
if system is under stress and got memory allocation error.

Ring pointer was used as an indicator of failure, but this is
not correct since only ring data is allocated/deallocated.
Ring itself is an array member.

Changing ring allocation functions to return error code directly.
This simplifies error handling and eliminates aq_ring_free
on higher layer.

Signed-off-by: Igor Russkikh <irusskikh at marvell.com>
Link: https://lore.kernel.org/r/20231213095044.23146-1-irusskikh@marvell.com
Signed-off-by: Jakub Kicinski <kuba at kernel.org>
(backported from commit b3cb7a830a24527877b0bc900b9bd74a96aea928)
[mpellizzer: adjusted context mainly due to missing commits:
0d14657f408302 net: atlantic: Implement xdp control plane
94ad94558b0fbf1 net: aquantia: add PTP rings infrastructure
which introduce a new feature not needed in Focal, and:
8ce84271697a23 net: atlantic: changes for multi-TC support
which moves ring allocation/deallocation out of aq_vec_alloc()/aq_vec_free()]
CVE-2023-52664
Signed-off-by: Massimiliano Pellizzer <massimiliano.pellizzer at canonical.com>
---
 .../net/ethernet/aquantia/atlantic/aq_ring.c  | 54 +++++--------------
 .../net/ethernet/aquantia/atlantic/aq_ring.h  | 16 +++---
 .../net/ethernet/aquantia/atlantic/aq_vec.c   | 15 +++---
 3 files changed, 28 insertions(+), 57 deletions(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index 4c22f119ac62..263adac56ec2 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -92,8 +92,8 @@ static int aq_get_rxpages(struct aq_ring_s *self, struct aq_ring_buff_s *rxbuf,
 	return 0;
 }
 
-static struct aq_ring_s *aq_ring_alloc(struct aq_ring_s *self,
-				       struct aq_nic_s *aq_nic)
+static int aq_ring_alloc(struct aq_ring_s *self,
+			 struct aq_nic_s *aq_nic)
 {
 	int err = 0;
 
@@ -115,44 +115,29 @@ static struct aq_ring_s *aq_ring_alloc(struct aq_ring_s *self,
 err_exit:
 	if (err < 0) {
 		aq_ring_free(self);
-		self = NULL;
 	}
-	return self;
+
+	return err;
 }
 
-struct aq_ring_s *aq_ring_tx_alloc(struct aq_ring_s *self,
-				   struct aq_nic_s *aq_nic,
-				   unsigned int idx,
-				   struct aq_nic_cfg_s *aq_nic_cfg)
+int aq_ring_tx_alloc(struct aq_ring_s *self,
+		     struct aq_nic_s *aq_nic,
+		     unsigned int idx,
+		     struct aq_nic_cfg_s *aq_nic_cfg)
 {
-	int err = 0;
-
 	self->aq_nic = aq_nic;
 	self->idx = idx;
 	self->size = aq_nic_cfg->txds;
 	self->dx_size = aq_nic_cfg->aq_hw_caps->txd_size;
 
-	self = aq_ring_alloc(self, aq_nic);
-	if (!self) {
-		err = -ENOMEM;
-		goto err_exit;
-	}
-
-err_exit:
-	if (err < 0) {
-		aq_ring_free(self);
-		self = NULL;
-	}
-	return self;
+	return aq_ring_alloc(self, aq_nic);
 }
 
-struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
-				   struct aq_nic_s *aq_nic,
-				   unsigned int idx,
-				   struct aq_nic_cfg_s *aq_nic_cfg)
+int aq_ring_rx_alloc(struct aq_ring_s *self,
+		     struct aq_nic_s *aq_nic,
+		     unsigned int idx,
+		     struct aq_nic_cfg_s *aq_nic_cfg)
 {
-	int err = 0;
-
 	self->aq_nic = aq_nic;
 	self->idx = idx;
 	self->size = aq_nic_cfg->rxds;
@@ -163,18 +148,7 @@ struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
 	if (aq_nic_cfg->rxpageorder > self->page_order)
 		self->page_order = aq_nic_cfg->rxpageorder;
 
-	self = aq_ring_alloc(self, aq_nic);
-	if (!self) {
-		err = -ENOMEM;
-		goto err_exit;
-	}
-
-err_exit:
-	if (err < 0) {
-		aq_ring_free(self);
-		self = NULL;
-	}
-	return self;
+	return aq_ring_alloc(self, aq_nic);
 }
 
 int aq_ring_init(struct aq_ring_s *self)
diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.h b/drivers/net/ethernet/aquantia/atlantic/aq_ring.h
index 47abd09d06c2..53ed9a55a14d 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.h
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.h
@@ -153,14 +153,14 @@ static inline unsigned int aq_ring_avail_dx(struct aq_ring_s *self)
 		self->sw_head - self->sw_tail - 1);
 }
 
-struct aq_ring_s *aq_ring_tx_alloc(struct aq_ring_s *self,
-				   struct aq_nic_s *aq_nic,
-				   unsigned int idx,
-				   struct aq_nic_cfg_s *aq_nic_cfg);
-struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
-				   struct aq_nic_s *aq_nic,
-				   unsigned int idx,
-				   struct aq_nic_cfg_s *aq_nic_cfg);
+int aq_ring_tx_alloc(struct aq_ring_s *self,
+		     struct aq_nic_s *aq_nic,
+		     unsigned int idx,
+		     struct aq_nic_cfg_s *aq_nic_cfg);
+int aq_ring_rx_alloc(struct aq_ring_s *self,
+		     struct aq_nic_s *aq_nic,
+		     unsigned int idx,
+		     struct aq_nic_cfg_s *aq_nic_cfg);
 int aq_ring_init(struct aq_ring_s *self);
 void aq_ring_rx_deinit(struct aq_ring_s *self);
 void aq_ring_free(struct aq_ring_s *self);
diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_vec.c b/drivers/net/ethernet/aquantia/atlantic/aq_vec.c
index a95c263a45aa..5272d44e29b4 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_vec.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_vec.c
@@ -133,21 +133,18 @@ struct aq_vec_s *aq_vec_alloc(struct aq_nic_s *aq_nic, unsigned int idx,
 						self->tx_rings,
 						self->aq_ring_param.vec_idx);
 
-		ring = aq_ring_tx_alloc(&self->ring[i][AQ_VEC_TX_ID], aq_nic,
-					idx_ring, aq_nic_cfg);
-		if (!ring) {
-			err = -ENOMEM;
+		ring = &self->ring[i][AQ_VEC_TX_ID];
+		err = aq_ring_tx_alloc(ring, aq_nic, idx_ring, aq_nic_cfg);
+		if (err)
 			goto err_exit;
-		}
 
 		++self->tx_rings;
 
 		aq_nic_set_tx_ring(aq_nic, idx_ring, ring);
 
-		ring = aq_ring_rx_alloc(&self->ring[i][AQ_VEC_RX_ID], aq_nic,
-					idx_ring, aq_nic_cfg);
-		if (!ring) {
-			err = -ENOMEM;
+		ring = &self->ring[i][AQ_VEC_RX_ID];
+		err = aq_ring_rx_alloc(ring, aq_nic, idx_ring, aq_nic_cfg);
+		if (err) {
 			goto err_exit;
 		}
 
-- 
2.43.0