[PATCH v3 3/4] soc: qcom: smem: validate private item payloads

[Albert Esteve]

From: Sarannya S <quic_sarannya@xxxxxxxxxxxxxxxx>

Validate a matching entry's size and padding even when the caller does
not request the length, and check that the payload stays inside the
same region as the header.

Signed-off-by: Sarannya S <quic_sarannya@xxxxxxxxxxxxxxxx>
Signed-off-by: Pranav Mahesh Phansalkar <quic_pphansal@xxxxxxxxxxxxxxxx>
Signed-off-by: Sudeepgoud Patil <quic_sudeepgo@xxxxxxxxxxxxxxxx>
Signed-off-by: Albert Esteve <aesteve@xxxxxxxxxx>
---
 drivers/soc/qcom/smem.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index 9bf0ec32c9f1..393257cbe5e1 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -615,6 +615,7 @@ static void *qcom_smem_get_private(struct qcom_smem *smem,
 	struct smem_private_entry *next_e;
 	struct smem_partition_header *phdr;
 	void *item_ptr, *p_end;
+	size_t entry_size = 0;
 	u32 padding_data;
 	u32 e_size;
 
@@ -634,20 +635,21 @@ static void *qcom_smem_get_private(struct qcom_smem *smem,
 			goto invalid_canary;
 
 		if (le16_to_cpu(e->item) == item) {
-			if (size != NULL) {
-				e_size = le32_to_cpu(e->size);
-				padding_data = le16_to_cpu(e->padding_data);
+			e_size = le32_to_cpu(e->size);
+			padding_data = le16_to_cpu(e->padding_data);
 
-				if (WARN_ON(e_size > part->size || padding_data > e_size))
-					return ERR_PTR(-EINVAL);
-
-				*size = e_size - padding_data;
-			}
+			if (e_size < part->size && padding_data < e_size)
+				entry_size = e_size - padding_data;
+			else
+				return ERR_PTR(-EINVAL);
 
 			item_ptr = uncached_entry_to_item(e);
-			if (WARN_ON(item_ptr > p_end))
+			if (WARN_ON(!IN_PARTITION_RANGE(item_ptr, entry_size, e, uncached_end)))
 				return ERR_PTR(-EINVAL);
 
+			if (size != NULL)
+				*size = entry_size;
+
 			return item_ptr;
 		}
 
@@ -677,20 +679,21 @@ static void *qcom_smem_get_private(struct qcom_smem *smem,
 			goto invalid_canary;
 
 		if (le16_to_cpu(e->item) == item) {
-			if (size != NULL) {
-				e_size = le32_to_cpu(e->size);
-				padding_data = le16_to_cpu(e->padding_data);
+			e_size = le32_to_cpu(e->size);
+			padding_data = le16_to_cpu(e->padding_data);
 
-				if (WARN_ON(e_size > part->size || padding_data > e_size))
-					return ERR_PTR(-EINVAL);
-
-				*size = e_size - padding_data;
-			}
+			if (e_size < part->size && padding_data < e_size)
+				entry_size = e_size - padding_data;
+			else
+				return ERR_PTR(-EINVAL);
 
 			item_ptr = cached_entry_to_item(e);
-			if (WARN_ON(item_ptr < (void *)phdr))
+			if (WARN_ON(!IN_PARTITION_RANGE(item_ptr, entry_size, cached_end, e)))
 				return ERR_PTR(-EINVAL);
 
+			if (size != NULL)
+				*size = entry_size;
+
 			return item_ptr;
 		}
 

-- 
2.55.0