[PATCH 6.6.y] drm/amd/pm: fix pptable use-after-free
Sasha Levin <[email protected]>
| Newsgroups | org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
From: Yang Wang <[email protected]> [ Upstream commit bb493058c35c8676e48269ab6732688ea733d23c ] amdgpu_dpm_get_pp_table() returns a pointer to a driver-owned power table after dropping adev->pm.mutex. The sysfs path then copies from that pointer. A concurrent pp_table write can replace and free the allocation during the copy, causing a use-after-free. Change the DPM interface to copy into caller-provided storage while the mutex is held. Keep the size-only query for attribute discovery without exposing the driver-owned pointer. Fixes: 1684d3ba4885 ("drm/amd/amdgpu: change pptable output format from ASCII to binary") Signed-off-by: Yang Wang <[email protected]> Reviewed-by: Kenneth Feng <[email protected]> Signed-off-by: Alex Deucher <[email protected]> (cherry picked from commit f6eed7acfd30099ef7baeb6ba45bb59daad80631) Cc: [email protected] [ kept 6.18's existing `if (!pp_funcs->get_pp_table) return 0;` guard instead of upstream's SR-IOV/SCPM `-EOPNOTSUPP` guard and dropped the `default_attr_update()` hunk whose `pp_table` branch doesn't exist yet ] Signed-off-by: Sasha Levin <[email protected]> --- drivers/gpu/drm/amd/pm/amdgpu_dpm.c | 15 +++++++++++++-- drivers/gpu/drm/amd/pm/amdgpu_pm.c | 8 +------- drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h | 3 ++- 3 files changed, 16 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c index 078aaaa531628..467fc9f03f8a5 100644 --- a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c +++ b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c @@ -996,17 +996,28 @@ int amdgpu_dpm_dispatch_task(struct amdgpu_device *adev, return ret; } -int amdgpu_dpm_get_pp_table(struct amdgpu_device *adev, char **table) +int amdgpu_dpm_get_pp_table(struct amdgpu_device *adev, char *table, + size_t size) { const struct amd_pm_funcs *pp_funcs = adev->powerplay.pp_funcs; + char *pptable = NULL; int ret = 0; + if ((!table && size) || (table && !size)) + return -EINVAL; + if (!pp_funcs->get_pp_table) return 0; mutex_lock(&adev->pm.mutex); ret = pp_funcs->get_pp_table(adev->powerplay.pp_handle, - table); + &pptable); + if (ret > 0 && !pptable) { + ret = -EINVAL; + } else if (ret > 0 && table) { + ret = min_t(size_t, ret, size); + memcpy(table, pptable, ret); + } mutex_unlock(&adev->pm.mutex); return ret; diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c index 93fe215986d39..15dd6a32ada16 100644 --- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c @@ -496,7 +496,6 @@ static ssize_t amdgpu_get_pp_table(struct device *dev, { struct drm_device *ddev = dev_get_drvdata(dev); struct amdgpu_device *adev = drm_to_adev(ddev); - char *table = NULL; int size, ret; if (amdgpu_in_reset(adev)) @@ -510,7 +509,7 @@ static ssize_t amdgpu_get_pp_table(struct device *dev, return ret; } - size = amdgpu_dpm_get_pp_table(adev, &table); + size = amdgpu_dpm_get_pp_table(adev, buf, PAGE_SIZE - 1); pm_runtime_mark_last_busy(ddev->dev); pm_runtime_put_autosuspend(ddev->dev); @@ -518,11 +517,6 @@ static ssize_t amdgpu_get_pp_table(struct device *dev, if (size <= 0) return size; - if (size >= PAGE_SIZE) - size = PAGE_SIZE - 1; - - memcpy(buf, table, size); - return size; } diff --git a/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h b/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h index 42172b00be66d..783deac8510eb 100644 --- a/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h +++ b/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h @@ -463,7 +463,8 @@ int amdgpu_dpm_get_pp_num_states(struct amdgpu_device *adev, int amdgpu_dpm_dispatch_task(struct amdgpu_device *adev, enum amd_pp_task task_id, enum amd_pm_state_type *user_state); -int amdgpu_dpm_get_pp_table(struct amdgpu_device *adev, char **table); +int amdgpu_dpm_get_pp_table(struct amdgpu_device *adev, char *table, + size_t size); int amdgpu_dpm_set_fine_grain_clk_vol(struct amdgpu_device *adev, uint32_t type, long *input, -- 2.53.0