drm/amdgpu: Fix NULL dereference in dpm sysfs handlers

commit 38e0c89a19fd13f28d2b4721035160a3e66e270b upstream.

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 <me@woland.xyz>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Paweł Gronowski 2020-07-19 17:54:53 +02:00 committed by Greg Kroah-Hartman
parent c3de96686d
commit 33ab3f2dc4

View File

@ -691,8 +691,7 @@ 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, &parameter[parameter_size]);
if (ret)
return -EINVAL;
@ -883,8 +882,7 @@ 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)
@ -1300,8 +1298,7 @@ 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, &parameter[parameter_size]);
if (ret) {
count = -EINVAL;