From: Paweł Gronowski me@woland.xyz
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
--- drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c @@ -691,8 +691,7 @@ static ssize_t amdgpu_set_pp_od_clk_volt 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; @@ -883,8 +882,7 @@ static ssize_t amdgpu_read_mask(const ch 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_profi 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) { count = -EINVAL;