[PATCH v3] accel/qaic: Use check_add_overflow in sahara for 64b types

[PATCH v3] accel/qaic: Use check_add_overflow in sahara for 64b types

[Youssef Samir]

From: Zack McKevitt <zmckevit@qti.qualcomm.com>

Use check_add_overflow instead of size_add in sahara when
64b types are being added to ensure compatibility with 32b
systems. The size_add function parameters are of size_t, so
64b data types may be truncated when cast to size_t on 32b
systems. When using check_add_overflow, no type casts are made,
making it a more portable option.

Signed-off-by: Zack McKevitt <zmckevit@qti.qualcomm.com>
Signed-off-by: Youssef Samir <youssef.abdulrahman@oss.qualcomm.com>
Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
---
Changes in V3:
- Remove the min() to min_t() changes
- Link to V2: https://lore.kernel.org/all/20251014170927.3908383-1-youssef.abdulrahman@oss.qualcomm.com

Changes in V2:
- Use explicit casts with check_*_overflow() calls
- Replace min() with min_t()
- Link to V1: https://lore.kernel.org/all/20251007154853.417114-1-youssef.abdulrahman@oss.qualcomm.com
---
 drivers/accel/qaic/sahara.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/accel/qaic/sahara.c b/drivers/accel/qaic/sahara.c
index 3ebcc1f7ff58..351348f06755 100644
--- a/drivers/accel/qaic/sahara.c
+++ b/drivers/accel/qaic/sahara.c
@@ -538,6 +538,7 @@ static void sahara_parse_dump_table(struct sahara_context *context)
 	struct sahara_memory_dump_meta_v1 *dump_meta;
 	u64 table_nents;
 	u64 dump_length;
+	u64 mul_bytes;
 	int ret;
 	u64 i;
 
@@ -551,8 +552,9 @@ static void sahara_parse_dump_table(struct sahara_context *context)
 		dev_table[i].description[SAHARA_TABLE_ENTRY_STR_LEN - 1] = 0;
 		dev_table[i].filename[SAHARA_TABLE_ENTRY_STR_LEN - 1] = 0;
 
-		dump_length = size_add(dump_length, le64_to_cpu(dev_table[i].length));
-		if (dump_length == SIZE_MAX) {
+		if (check_add_overflow(dump_length,
+				       le64_to_cpu(dev_table[i].length),
+				       &dump_length)) {
 			/* Discard the dump */
 			sahara_send_reset(context);
 			return;
@@ -568,14 +570,17 @@ static void sahara_parse_dump_table(struct sahara_context *context)
 			dev_table[i].filename);
 	}
 
-	dump_length = size_add(dump_length, sizeof(*dump_meta));
-	if (dump_length == SIZE_MAX) {
+	if (check_add_overflow(dump_length, (u64)sizeof(*dump_meta), &dump_length)) {
 		/* Discard the dump */
 		sahara_send_reset(context);
 		return;
 	}
-	dump_length = size_add(dump_length, size_mul(sizeof(*image_out_table), table_nents));
-	if (dump_length == SIZE_MAX) {
+	if (check_mul_overflow((u64)sizeof(*image_out_table), table_nents, &mul_bytes)) {
+		/* Discard the dump */
+		sahara_send_reset(context);
+		return;
+	}
+	if (check_add_overflow(dump_length, mul_bytes, &dump_length)) {
 		/* Discard the dump */
 		sahara_send_reset(context);
 		return;
-- 
2.43.0

Re: [PATCH v3] accel/qaic: Use check_add_overflow in sahara for 64b types

[Carl Vanderlip]

On 10/15/2025 9:54 AM, Youssef Samir wrote:
> From: Zack McKevitt <zmckevit@qti.qualcomm.com>
> 
> Use check_add_overflow instead of size_add in sahara when
> 64b types are being added to ensure compatibility with 32b
> systems. The size_add function parameters are of size_t, so
> 64b data types may be truncated when cast to size_t on 32b
> systems. When using check_add_overflow, no type casts are made,
> making it a more portable option.
> 
> Signed-off-by: Zack McKevitt <zmckevit@qti.qualcomm.com>
> Signed-off-by: Youssef Samir <youssef.abdulrahman@oss.qualcomm.com>
> Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
> ---
> Changes in V3:
> - Remove the min() to min_t() changes
> - Link to V2: https://lore.kernel.org/all/20251014170927.3908383-1-youssef.abdulrahman@oss.qualcomm.com
> 
> Changes in V2:
> - Use explicit casts with check_*_overflow() calls
> - Replace min() with min_t()
> - Link to V1: https://lore.kernel.org/all/20251007154853.417114-1-youssef.abdulrahman@oss.qualcomm.com
> ---

Reviewed-by: Carl Vanderlip <carl.vanderlip@oss.qualcomm.com>

Re: [PATCH v3] accel/qaic: Use check_add_overflow in sahara for 64b types

[Jeff Hugo]

On 10/15/2025 10:54 AM, Youssef Samir wrote:
> From: Zack McKevitt <zmckevit@qti.qualcomm.com>
> 
> Use check_add_overflow instead of size_add in sahara when
> 64b types are being added to ensure compatibility with 32b
> systems. The size_add function parameters are of size_t, so
> 64b data types may be truncated when cast to size_t on 32b
> systems. When using check_add_overflow, no type casts are made,
> making it a more portable option.
> 
> Signed-off-by: Zack McKevitt <zmckevit@qti.qualcomm.com>
> Signed-off-by: Youssef Samir <youssef.abdulrahman@oss.qualcomm.com>
> Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>

Pushed to drm-misc-next

-Jeff