This is a note to let you know that I've just added the patch titled drm/amdgpu: Prevent shift wrapping in amdgpu_read_mask() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amdgpu-prevent-shift-wrapping-in-amdgpu_read_mas.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 92f524a6ac006b01fb7cec832348578139ad0a90 Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Tue Feb 2 08:56:36 2021 +0300 drm/amdgpu: Prevent shift wrapping in amdgpu_read_mask() [ Upstream commit c915ef890d5dc79f483e1ca3b3a5b5f1a170690c ] If the user passes a "level" value which is higher than 31 then that leads to shift wrapping. The undefined behavior will lead to a syzkaller stack dump. Fixes: 5632708f4452 ("drm/amd/powerplay: add dpm force multiple levels on cz/tonga/fiji/polaris (v2)") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c index 3f744e72912f1..bcb7ab5c602d1 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c @@ -870,7 +870,7 @@ static ssize_t amdgpu_get_pp_dpm_sclk(struct device *dev, static ssize_t amdgpu_read_mask(const char *buf, size_t count, uint32_t *mask) { int ret; - long level; + unsigned long level; char *sub_str = NULL; char *tmp; char buf_cpy[AMDGPU_MASK_BUF_MAX + 1]; @@ -886,8 +886,8 @@ static ssize_t amdgpu_read_mask(const char *buf, size_t count, uint32_t *mask) while (tmp[0]) { sub_str = strsep(&tmp, delimiter); if (strlen(sub_str)) { - ret = kstrtol(sub_str, 0, &level); - if (ret) + ret = kstrtoul(sub_str, 0, &level); + if (ret || level > 31) return -EINVAL; *mask |= 1 << level; } else