drm/radeon: fix array out-of-bounds read and write issues

BugLink: https://bugs.launchpad.net/bugs/1892417
[ Upstream commit 7ee78aff9de13d5dccba133f4a0de5367194b243 ]

There is an off-by-one bounds check on the index into arrays
table->mc_reg_address and table->mc_reg_table_entry[k].mc_data[j] that
can lead to reads and writes outside of arrays. Fix the bound checking
off-by-one error.

Addresses-Coverity: ("Out-of-bounds read/write")
Fixes: cc8dbbb4f62a ("drm/radeon: add dpm support for CI dGPUs (v2)")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/gpu/drm/radeon/ci_dpm.c b/drivers/gpu/drm/radeon/ci_dpm.c
index f9685cce1652014ddc86de7e9b7bbdeb5e76e661..1e62e7bbf1b1d1213b8eb1e8e40f9459583e07bc 100644 (file)
--- a/drivers/gpu/drm/radeon/ci_dpm.c
+++ b/drivers/gpu/drm/radeon/ci_dpm.c
@@ -4366,7 +4366,7 @@ static int ci_set_mc_special_registers(struct radeon_device *rdev,
                                        table->mc_reg_table_entry[k].mc_data[j] |= 0x100;
                        }
                        j++;
-                       if (j > SMU7_DISCRETE_MC_REGISTER_ARRAY_SIZE)
+                       if (j >= SMU7_DISCRETE_MC_REGISTER_ARRAY_SIZE)
                                return -EINVAL;
 
                        if (!pi->mem_gddr5) {