[PATCH net 01/10] idpf: bound interrupt-vector register fill to the allocated array

[Tony Nguyen <anthony.l.nguyen@intel.com>]

From: Michael Bommarito <michael.bommarito@gmail.com>

idpf_get_reg_intr_vecs() fills the caller-allocated reg_vals[] array from
the VIRTCHNL2_OP_ALLOC_VECTORS reply in adapter->req_vec_chunks, bounding
its inner loop only by the per-chunk num_vectors. The array is sized
separately: idpf_intr_reg_init() allocates
kzalloc_objs(struct idpf_vec_regs, total_vecs) from
caps.num_allocated_vectors and only checks the returned count after the
fill. The sum of per-chunk num_vectors is never reconciled against
total_vecs, so a reply with a small num_allocated_vectors but chunks
summing higher writes past the end of reg_vals[].

Impact: a control plane (a PF or hypervisor device model) that returns a
VIRTCHNL2_OP_ALLOC_VECTORS reply whose per-chunk num_vectors sum exceeds
num_allocated_vectors writes struct idpf_vec_regs entries past the end of
the reg_vals kmalloc allocation (KASAN slab-out-of-bounds write).

Bound the fill loop to the array capacity passed in by the callers,
mirroring the sibling idpf_vport_get_q_reg(). The existing
num_regs < num_vecs check then rejects an undersized reply without the
out-of-bounds write happening first.

Fixes: d4d558718266 ("idpf: initialize interrupts and enable vport")
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Samuel Salin <Samuel.salin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 drivers/net/ethernet/intel/idpf/idpf_dev.c      | 2 +-
 drivers/net/ethernet/intel/idpf/idpf_vf_dev.c   | 2 +-
 drivers/net/ethernet/intel/idpf/idpf_virtchnl.c | 5 +++--
 drivers/net/ethernet/intel/idpf/idpf_virtchnl.h | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/idpf/idpf_dev.c b/drivers/net/ethernet/intel/idpf/idpf_dev.c
index 1a0c71c95ef1..4079a787657f 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_dev.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_dev.c
@@ -87,7 +87,7 @@ static int idpf_intr_reg_init(struct idpf_vport *vport,
 	if (!reg_vals)
 		return -ENOMEM;
 
-	num_regs = idpf_get_reg_intr_vecs(adapter, reg_vals);
+	num_regs = idpf_get_reg_intr_vecs(adapter, reg_vals, total_vecs);
 	if (num_regs < num_vecs) {
 		err = -EINVAL;
 		goto free_reg_vals;
diff --git a/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c b/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
index a07d7e808ca9..6726084f6cfa 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
@@ -86,7 +86,7 @@ static int idpf_vf_intr_reg_init(struct idpf_vport *vport,
 	if (!reg_vals)
 		return -ENOMEM;
 
-	num_regs = idpf_get_reg_intr_vecs(adapter, reg_vals);
+	num_regs = idpf_get_reg_intr_vecs(adapter, reg_vals, total_vecs);
 	if (num_regs < num_vecs) {
 		err = -EINVAL;
 		goto free_reg_vals;
diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
index dc5ad784f456..8bd6cca64c9b 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
@@ -1318,11 +1318,12 @@ idpf_vport_init_queue_reg_chunks(struct idpf_vport_config *vport_config,
  * idpf_get_reg_intr_vecs - Get vector queue register offset
  * @adapter: adapter structure to get the vector chunks
  * @reg_vals: Register offsets to store in
+ * @num_vecs: number of entries the @reg_vals array can hold
  *
  * Return: number of registers that got populated
  */
 int idpf_get_reg_intr_vecs(struct idpf_adapter *adapter,
-			   struct idpf_vec_regs *reg_vals)
+			   struct idpf_vec_regs *reg_vals, int num_vecs)
 {
 	struct virtchnl2_vector_chunks *chunks;
 	struct idpf_vec_regs reg_val;
@@ -1346,7 +1347,7 @@ int idpf_get_reg_intr_vecs(struct idpf_adapter *adapter,
 		dynctl_reg_spacing = le32_to_cpu(chunk->dynctl_reg_spacing);
 		itrn_reg_spacing = le32_to_cpu(chunk->itrn_reg_spacing);
 
-		for (i = 0; i < num_vec; i++) {
+		for (i = 0; i < num_vec && num_regs < num_vecs; i++) {
 			reg_vals[num_regs].dyn_ctl_reg = reg_val.dyn_ctl_reg;
 			reg_vals[num_regs].itrn_reg = reg_val.itrn_reg;
 			reg_vals[num_regs].itrn_index_spacing =
diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.h b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.h
index 6876e3ed9d1b..9b1c9c86f6ea 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.h
+++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.h
@@ -104,7 +104,7 @@ int idpf_vc_core_init(struct idpf_adapter *adapter);
 void idpf_vc_core_deinit(struct idpf_adapter *adapter);
 
 int idpf_get_reg_intr_vecs(struct idpf_adapter *adapter,
-			   struct idpf_vec_regs *reg_vals);
+			   struct idpf_vec_regs *reg_vals, int num_vecs);
 int idpf_queue_reg_init(struct idpf_vport *vport,
 			struct idpf_q_vec_rsrc *rsrc,
 			struct idpf_queue_id_reg_info *chunks);
-- 
2.47.1