From 38e0c89a19fd13f28d2b4721035160a3e66e270b Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pawe=C5=82=20Gronowski?= Date: Sun, 19 Jul 2020 17:54:53 +0200 Subject: [PATCH] drm/amdgpu: Fix NULL dereference in dpm sysfs handlers MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit NULL dereference occurs when string that is not ended with space or newline is written to some dpm sysfs interface (for example pp_dpm_sclk). This happens because strsep replaces the tmp with NULL if the delimiter is not present in string, which is then dereferenced by tmp[0]. Reproduction example: sudo sh -c 'echo -n 1 > /sys/class/drm/card0/device/pp_dpm_sclk' Signed-off-by: Paweł Gronowski Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org --- drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c index 02e6f8c4..ebb8a28 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c @@ -778,8 +778,7 @@ static ssize_t amdgpu_set_pp_od_clk_voltage(struct device *dev, tmp_str++; while (isspace(*++tmp_str)); - while (tmp_str[0]) { - sub_str = strsep(&tmp_str, delimiter); + while ((sub_str = strsep(&tmp_str, delimiter)) != NULL) { ret = kstrtol(sub_str, 0, ¶meter[parameter_size]); if (ret) return -EINVAL; @@ -1039,8 +1038,7 @@ static ssize_t amdgpu_read_mask(const char *buf, size_t count, uint32_t *mask) memcpy(buf_cpy, buf, bytes); buf_cpy[bytes] = '\0'; tmp = buf_cpy; - while (tmp[0]) { - sub_str = strsep(&tmp, delimiter); + while ((sub_str = strsep(&tmp, delimiter)) != NULL) { if (strlen(sub_str)) { ret = kstrtol(sub_str, 0, &level); if (ret) @@ -1637,8 +1635,7 @@ static ssize_t amdgpu_set_pp_power_profile_mode(struct device *dev, i++; memcpy(buf_cpy, buf, count-i); tmp_str = buf_cpy; - while (tmp_str[0]) { - sub_str = strsep(&tmp_str, delimiter); + while ((sub_str = strsep(&tmp_str, delimiter)) != NULL) { ret = kstrtol(sub_str, 0, ¶meter[parameter_size]); if (ret) return -EINVAL; -- 2.7.4