Merge branch 'net-enetc-sr-iov-robustness-and-security-fixes'

Wei Fang says:

====================
net: enetc: SR-IOV robustness and security fixes

This patch series addresses a number of robustness, security, and
correctness issues in the ENETC driver's SR-IOV subsystem, focusing
primarily on the VF-to-PF mailbox communication path.

The series can be grouped into the following categories:

1. DoS and security fixes:
   - Prevent an unbounded loop DoS in the VF-to-PF message handler,
     which could be triggered by a malicious or misbehaving VF.
   - Fix a TOCTOU (Time-of-Check-Time-of-Use) race and add proper
     validation of VF MAC addresses to prevent spoofing or invalid
     configuration from being applied.

2. Race condition fixes:
   - Fix a race condition in VF MAC address configuration that could
     lead to inconsistent state between the VF request and PF
     application.
   - Fix a race condition during SR-IOV teardown that could cause
     VF->PF mailbox operations to time out, resulting in unnecessary
     errors during shutdown.

3. Memory safety fixes:
   - Fix a DMA write to freed memory in enetc_msg_free_mbx(), which
     could cause silent memory corruption or system instability.

4. Error handling and initialization fixes:
   - Fix missing error code propagation when pf->vf_state allocation
     fails, ensuring callers receive a proper errno instead of
     succeeding silently.
   - Fix incorrect mailbox message status values returned to VFs,
     which could cause VFs to misinterpret PF responses.
   - Fix initialization order to prevent the use of uninitialized
     resources during driver probe, which could cause undefined
     behavior on certain configurations.

5. Diagnostics improvement:
   - Add rate limiting to VF mailbox error messages to prevent log
     flooding in the presence of a misbehaving VF.

These fixes improve the overall stability and security of the ENETC
SR-IOV implementation, particularly in multi-tenant environments where
VFs may be assigned to untrusted guests.
====================

Link: https://patch.msgid.link/20260520064421.91569-1-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 127 insertions, 70 deletions

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_hw.h b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
index 662e4fbafb74..e58cc81d199d 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_hw.h
+++ b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
@@ -56,11 +56,21 @@ static inline u32 enetc_vsi_set_msize(u32 size)
 }
 
 #define ENETC_PSIMSGRR	0x204
-#define ENETC_PSIMSGRR_MR_MASK	GENMASK(2, 1)
-#define ENETC_PSIMSGRR_MR(n) BIT((n) + 1) /* n = VSI index */
 #define ENETC_PSIVMSGRCVAR0(n)	(0x210 + (n) * 0x8) /* n = VSI index */
 #define ENETC_PSIVMSGRCVAR1(n)	(0x214 + (n) * 0x8)
 
+/* Message received mask, n is the active number of VSIs.
+ * It is available for ENETC_PSIMSGRR, ENETC_PSIIER, and
+ * ENETC_PSIIDR registers.
+ */
+#define ENETC_PSIMR_MASK(n)	\
+	({ typeof(n) _n = (n); (_n) ? GENMASK((_n), 1) : 0; })
+
+/* Message received bit, n is VSI index. It is available for
+ * ENETC_PSIMSGRR, ENETC_PSIIER, and ENETC_PSIIDR registers.
+ */
+#define ENETC_PSIMR_BIT(n)	BIT((n) + 1)
+
 #define ENETC_VSIMSGSR	0x204	/* RO */
 #define ENETC_VSIMSGSR_MB	BIT(0)
 #define ENETC_VSIMSGSR_MS	BIT(1)
@@ -94,7 +104,6 @@ static inline u32 enetc_vsi_set_msize(u32 size)
 #define ENETC_SICAPR1	0x904
 
 #define ENETC_PSIIER	0xa00
-#define ENETC_PSIIER_MR_MASK	GENMASK(2, 1)
 #define ENETC_PSIIDR	0xa08
 #define ENETC_SITXIDR	0xa18
 #define ENETC_SIRXIDR	0xa28
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_msg.c b/drivers/net/ethernet/freescale/enetc/enetc_msg.c
index 40d22ebe9224..c09635e7eb3d 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_msg.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_msg.c
@@ -3,18 +3,25 @@
 
 #include "enetc_pf.h"
 
-static void enetc_msg_disable_mr_int(struct enetc_hw *hw)
+static void enetc_msg_disable_mr_int(struct enetc_pf *pf)
 {
-	u32 psiier = enetc_rd(hw, ENETC_PSIIER);
+	struct enetc_hw *hw = &pf->si->hw;
+	u32 psiier;
+
+	psiier = enetc_rd(hw, ENETC_PSIIER) & ~ENETC_PSIMR_MASK(pf->num_vfs);
+
 	/* disable MR int source(s) */
-	enetc_wr(hw, ENETC_PSIIER, psiier & ~ENETC_PSIIER_MR_MASK);
+	enetc_wr(hw, ENETC_PSIIER, psiier);
 }
 
-static void enetc_msg_enable_mr_int(struct enetc_hw *hw)
+static void enetc_msg_enable_mr_int(struct enetc_pf *pf)
 {
-	u32 psiier = enetc_rd(hw, ENETC_PSIIER);
+	struct enetc_hw *hw = &pf->si->hw;
+	u32 psiier;
+
+	psiier = enetc_rd(hw, ENETC_PSIIER) | ENETC_PSIMR_MASK(pf->num_vfs);
 
-	enetc_wr(hw, ENETC_PSIIER, psiier | ENETC_PSIIER_MR_MASK);
+	enetc_wr(hw, ENETC_PSIIER, psiier);
 }
 
 static irqreturn_t enetc_msg_psi_msix(int irq, void *data)
@@ -22,7 +29,7 @@ static irqreturn_t enetc_msg_psi_msix(int irq, void *data)
 	struct enetc_si *si = (struct enetc_si *)data;
 	struct enetc_pf *pf = enetc_si_priv(si);
 
-	enetc_msg_disable_mr_int(&si->hw);
+	enetc_msg_disable_mr_int(pf);
 	schedule_work(&pf->msg_task);
 
 	return IRQ_HANDLED;
@@ -31,33 +38,35 @@ static irqreturn_t enetc_msg_psi_msix(int irq, void *data)
 static void enetc_msg_task(struct work_struct *work)
 {
 	struct enetc_pf *pf = container_of(work, struct enetc_pf, msg_task);
+	u32 mr_mask = ENETC_PSIMR_MASK(pf->num_vfs);
 	struct enetc_hw *hw = &pf->si->hw;
-	unsigned long mr_mask;
+	u32 mr_status;
 	int i;
 
-	for (;;) {
-		mr_mask = enetc_rd(hw, ENETC_PSIMSGRR) & ENETC_PSIMSGRR_MR_MASK;
-		if (!mr_mask) {
-			/* re-arm MR interrupts, w1c the IDR reg */
-			enetc_wr(hw, ENETC_PSIIDR, ENETC_PSIIER_MR_MASK);
-			enetc_msg_enable_mr_int(hw);
-			return;
-		}
+	mr_status = (enetc_rd(hw, ENETC_PSIMSGRR) & mr_mask) |
+		    (enetc_rd(hw, ENETC_PSIIDR) & mr_mask);
+	if (!mr_status)
+		goto out;
 
-		for (i = 0; i < pf->num_vfs; i++) {
-			u32 psimsgrr;
-			u16 msg_code;
+	for (i = 0; i < pf->num_vfs; i++) {
+		u32 psimsgrr;
+		u16 msg_code;
+
+		if (!(ENETC_PSIMR_BIT(i) & mr_status))
+			continue;
 
-			if (!(ENETC_PSIMSGRR_MR(i) & mr_mask))
-				continue;
+		enetc_msg_handle_rxmsg(pf, i, &msg_code);
 
-			enetc_msg_handle_rxmsg(pf, i, &msg_code);
+		/* w1c to clear the corresponding VF MR bit */
+		enetc_wr(hw, ENETC_PSIIDR, ENETC_PSIMR_BIT(i));
 
-			psimsgrr = ENETC_SIMSGSR_SET_MC(msg_code);
-			psimsgrr |= ENETC_PSIMSGRR_MR(i); /* w1c */
-			enetc_wr(hw, ENETC_PSIMSGRR, psimsgrr);
-		}
+		psimsgrr = ENETC_SIMSGSR_SET_MC(msg_code);
+		psimsgrr |= ENETC_PSIMR_BIT(i); /* w1c */
+		enetc_wr(hw, ENETC_PSIMSGRR, psimsgrr);
 	}
+
+out:
+	enetc_msg_enable_mr_int(pf);
 }
 
 /* Init */
@@ -96,12 +105,12 @@ static void enetc_msg_free_mbx(struct enetc_si *si, int idx)
 	struct enetc_hw *hw = &si->hw;
 	struct enetc_msg_swbd *msg;
 
+	enetc_wr(hw, ENETC_PSIVMSGRCVAR0(idx), 0);
+	enetc_wr(hw, ENETC_PSIVMSGRCVAR1(idx), 0);
+
 	msg = &pf->rxmsg[idx];
 	dma_free_coherent(&si->pdev->dev, msg->size, msg->vaddr, msg->dma);
 	memset(msg, 0, sizeof(*msg));
-
-	enetc_wr(hw, ENETC_PSIVMSGRCVAR0(idx), 0);
-	enetc_wr(hw, ENETC_PSIVMSGRCVAR1(idx), 0);
 }
 
 int enetc_msg_psi_init(struct enetc_pf *pf)
@@ -109,6 +118,15 @@ int enetc_msg_psi_init(struct enetc_pf *pf)
 	struct enetc_si *si = pf->si;
 	int vector, i, err;
 
+	for (i = 0; i < pf->num_vfs; i++) {
+		err = enetc_msg_alloc_mbx(si, i);
+		if (err)
+			goto free_mbx;
+	}
+
+	/* initialize PSI mailbox */
+	INIT_WORK(&pf->msg_task, enetc_msg_task);
+
 	/* register message passing interrupt handler */
 	snprintf(pf->msg_int_name, sizeof(pf->msg_int_name), "%s-vfmsg",
 		 si->ndev->name);
@@ -117,32 +135,21 @@ int enetc_msg_psi_init(struct enetc_pf *pf)
 	if (err) {
 		dev_err(&si->pdev->dev,
 			"PSI messaging: request_irq() failed!\n");
-		return err;
+		goto free_mbx;
 	}
 
 	/* set one IRQ entry for PSI message receive notification (SI int) */
 	enetc_wr(&si->hw, ENETC_SIMSIVR, ENETC_SI_INT_IDX);
 
-	/* initialize PSI mailbox */
-	INIT_WORK(&pf->msg_task, enetc_msg_task);
-
-	for (i = 0; i < pf->num_vfs; i++) {
-		err = enetc_msg_alloc_mbx(si, i);
-		if (err)
-			goto err_init_mbx;
-	}
-
 	/* enable MR interrupts */
-	enetc_msg_enable_mr_int(&si->hw);
+	enetc_msg_enable_mr_int(pf);
 
 	return 0;
 
-err_init_mbx:
+free_mbx:
 	for (i--; i >= 0; i--)
 		enetc_msg_free_mbx(si, i);
 
-	free_irq(vector, si);
-
 	return err;
 }
 
@@ -151,14 +158,17 @@ void enetc_msg_psi_free(struct enetc_pf *pf)
 	struct enetc_si *si = pf->si;
 	int i;
 
+	/* disable MR interrupts */
+	enetc_msg_disable_mr_int(pf);
+
+	/* de-register message passing interrupt handler */
+	free_irq(pci_irq_vector(si->pdev, ENETC_SI_INT_IDX), si);
+
 	cancel_work_sync(&pf->msg_task);
 
-	/* disable MR interrupts */
-	enetc_msg_disable_mr_int(&si->hw);
+	/* MR interrupts may be re-enabled by workqueue */
+	enetc_msg_disable_mr_int(pf);
 
 	for (i = 0; i < pf->num_vfs; i++)
 		enetc_msg_free_mbx(si, i);
-
-	/* de-register message passing interrupt handler */
-	free_irq(pci_irq_vector(si->pdev, ENETC_SI_INT_IDX), si);
 }
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.c b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
index a12fd54a475f..3206b3daa1a0 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
@@ -252,8 +252,12 @@ static int enetc_pf_set_vf_mac(struct net_device *ndev, int vf, u8 *mac)
 		return -EADDRNOTAVAIL;
 
 	vf_state = &pf->vf_state[vf];
+
+	mutex_lock(&vf_state->lock);
 	vf_state->flags |= ENETC_VF_FLAG_PF_SET_MAC;
 	enetc_pf_set_primary_mac_addr(&priv->si->hw, vf + 1, mac);
+	mutex_unlock(&vf_state->lock);
+
 	return 0;
 }
 
@@ -478,49 +482,77 @@ static void enetc_configure_port(struct enetc_pf *pf)
 
 /* Messaging */
 static u16 enetc_msg_pf_set_vf_primary_mac_addr(struct enetc_pf *pf,
-						int vf_id)
+						int vf_id, void *msg)
 {
 	struct enetc_vf_state *vf_state = &pf->vf_state[vf_id];
-	struct enetc_msg_swbd *msg = &pf->rxmsg[vf_id];
-	struct enetc_msg_cmd_set_primary_mac *cmd;
+	struct enetc_msg_cmd_set_primary_mac *cmd = msg;
 	struct device *dev = &pf->si->pdev->dev;
-	u16 cmd_id;
+	u16 cmd_id = cmd->header.id;
 	char *addr;
 
-	cmd = (struct enetc_msg_cmd_set_primary_mac *)msg->vaddr;
-	cmd_id = cmd->header.id;
 	if (cmd_id != ENETC_MSG_CMD_MNG_ADD)
 		return ENETC_MSG_CMD_STATUS_FAIL;
 
 	addr = cmd->mac.sa_data;
-	if (vf_state->flags & ENETC_VF_FLAG_PF_SET_MAC)
-		dev_warn(dev, "Attempt to override PF set mac addr for VF%d\n",
-			 vf_id);
-	else
-		enetc_pf_set_primary_mac_addr(&pf->si->hw, vf_id + 1, addr);
+	if (!is_valid_ether_addr(addr)) {
+		dev_err_ratelimited(dev, "VF%d attempted to set invalid MAC\n",
+				    vf_id);
+		return ENETC_MSG_CMD_STATUS_FAIL;
+	}
+
+	mutex_lock(&vf_state->lock);
+	if (vf_state->flags & ENETC_VF_FLAG_PF_SET_MAC) {
+		mutex_unlock(&vf_state->lock);
+		dev_err_ratelimited(dev,
+				    "VF%d attempted to override PF set MAC\n",
+				    vf_id);
+		return ENETC_MSG_CMD_STATUS_FAIL;
+	}
+
+	enetc_pf_set_primary_mac_addr(&pf->si->hw, vf_id + 1, addr);
+	mutex_unlock(&vf_state->lock);
 
 	return ENETC_MSG_CMD_STATUS_OK;
 }
 
 void enetc_msg_handle_rxmsg(struct enetc_pf *pf, int vf_id, u16 *status)
 {
-	struct enetc_msg_swbd *msg = &pf->rxmsg[vf_id];
+	struct enetc_msg_swbd *msg_swbd = &pf->rxmsg[vf_id];
 	struct device *dev = &pf->si->pdev->dev;
 	struct enetc_msg_cmd_header *cmd_hdr;
 	u16 cmd_type;
+	u8 *msg;
 
-	*status = ENETC_MSG_CMD_STATUS_OK;
-	cmd_hdr = (struct enetc_msg_cmd_header *)msg->vaddr;
+	msg = kzalloc_objs(*msg, msg_swbd->size);
+	if (!msg) {
+		dev_err_ratelimited(dev,
+				    "Failed to allocate message buffer\n");
+		*status = ENETC_MSG_CMD_STATUS_FAIL;
+		return;
+	}
+
+	/* Currently, only ENETC_MSG_CMD_MNG_MAC command is supported, so
+	 * only sizeof(struct enetc_msg_cmd_set_primary_mac) bytes need to
+	 * be copied. This data already includes the cmd_type field, so it
+	 * can correctly return an error code.
+	 */
+	memcpy(msg, msg_swbd->vaddr,
+	       sizeof(struct enetc_msg_cmd_set_primary_mac));
+	cmd_hdr = (struct enetc_msg_cmd_header *)msg;
 	cmd_type = cmd_hdr->type;
 
 	switch (cmd_type) {
 	case ENETC_MSG_CMD_MNG_MAC:
-		*status = enetc_msg_pf_set_vf_primary_mac_addr(pf, vf_id);
+		*status = enetc_msg_pf_set_vf_primary_mac_addr(pf, vf_id, msg);
 		break;
 	default:
-		dev_err(dev, "command not supported (cmd_type: 0x%x)\n",
-			cmd_type);
+		*status = ENETC_MSG_CMD_STATUS_FAIL;
+		dev_err_ratelimited(dev,
+				    "command not supported (cmd_type: 0x%x)\n",
+				    cmd_type);
 	}
+
+	kfree(msg);
 }
 
 #ifdef CONFIG_PCI_IOV
@@ -531,9 +563,9 @@ static int enetc_sriov_configure(struct pci_dev *pdev, int num_vfs)
 	int err;
 
 	if (!num_vfs) {
+		pci_disable_sriov(pdev);
 		enetc_msg_psi_free(pf);
 		pf->num_vfs = 0;
-		pci_disable_sriov(pdev);
 	} else {
 		pf->num_vfs = num_vfs;
 
@@ -960,8 +992,13 @@ static int enetc_pf_probe(struct pci_dev *pdev,
 	if (pf->total_vfs) {
 		pf->vf_state = kzalloc_objs(struct enetc_vf_state,
 					    pf->total_vfs);
-		if (!pf->vf_state)
+		if (!pf->vf_state) {
+			err = -ENOMEM;
 			goto err_alloc_vf_state;
+		}
+
+		for (int i = 0; i < pf->total_vfs; i++)
+			mutex_init(&pf->vf_state[i].lock);
 	}
 
 	err = enetc_setup_mac_addresses(node, pf);
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.h b/drivers/net/ethernet/freescale/enetc/enetc_pf.h
index ae407e9e9ee7..35d484858c7b 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.h
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.h
@@ -14,6 +14,7 @@ enum enetc_vf_flags {
 };
 
 struct enetc_vf_state {
+	struct mutex lock; /* Prevent concurrent access */
 	enum enetc_vf_flags flags;
 };