From 363d0459eaf763aa3bf07875bee09866db6f30fb Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 23 Jul 2018 11:32:32 -0500 Subject: [PATCH 5037/5725] drm/amdgpu/pm: Fix potential Spectre v1 idx can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c:408 amdgpu_set_pp_force_state() warn: potential spectre issue 'data.states' Fix this by sanitizing idx before using it to index data.states Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c index 14bb1b3..2a78a3c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c @@ -31,7 +31,7 @@ #include #include #include - +#include static int amdgpu_debugfs_pm_init(struct amdgpu_device *adev); @@ -403,6 +403,7 @@ static ssize_t amdgpu_set_pp_force_state(struct device *dev, count = -EINVAL; goto fail; } + idx = array_index_nospec(idx, ARRAY_SIZE(data.states)); amdgpu_dpm_get_pp_num_states(adev, &data); state = data.states[idx]; -- 2.7.4