[PATCH] drm/amdgpu: Fix potential truncation by increasing SMU_FW_NAME_LEN

[Srinivasan Shanmugam]

Increases the size of SMU_FW_NAME_LEN from 0x24 (36 in decimal) to 0x2A
(42 in decimal). This change prevents truncation when the snprintf
function writes into the fw_name buffer in the smu_v11_0_init_microcode
function.

Previously, snprintf could write between 12 and 41 bytes into fw_name,
which can only hold 36 bytes. This could lead to truncation if the size
of the string is larger than 36 bytes. By increasing the size of
SMU_FW_NAME_LEN to 42, we ensure that fw_name can accommodate the
maximum possible string size.

Fixes the below with gcc W=1
drivers/gpu/drm/amd/amdgpu/../pm/swsmu/smu11/smu_v11_0.c: In function ‘smu_v11_0_init_microcode’:
drivers/gpu/drm/amd/amdgpu/../pm/swsmu/smu11/smu_v11_0.c:110:54: warning: ‘.bin’ directive output may be truncated writing 4 bytes into a region of size between 0 and 29 [-Wformat-truncation=]
  110 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s.bin", ucode_prefix);
      |                                                      ^~~~
drivers/gpu/drm/amd/amdgpu/../pm/swsmu/smu11/smu_v11_0.c:110:9: note: ‘snprintf’ output between 12 and 41 bytes into a destination of size 36
  110 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s.bin", ucode_prefix);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 6b54496238cc ("drm/amd: Convert SMUv11 microcode to use `amdgpu_ucode_ip_version_decode`")
Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Christian König <christian.koenig at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Lijo Lazar <lijo.lazar at amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
---
 drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h b/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
index a870bdd49a4e..3d98b0e0eec2 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
+++ b/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
@@ -35,7 +35,7 @@
 #define SMU_THERMAL_MINIMUM_ALERT_TEMP		0
 #define SMU_THERMAL_MAXIMUM_ALERT_TEMP		255
 #define SMU_TEMPERATURE_UNITS_PER_CENTIGRADES	1000
-#define SMU_FW_NAME_LEN			0x24
+#define SMU_FW_NAME_LEN			0x2A
 
 #define SMU_DPM_USER_PROFILE_RESTORE (1 << 0)
 #define SMU_CUSTOM_FAN_SPEED_RPM     (1 << 1)
-- 
2.34.1