[PATCH] drm/amdgpu: Fix even more out of bound writes from debugfs

[Harry Wentland]

On 2021-10-27 09:47, Harry Wentland wrote:
> 
> 
> On 2021-10-27 09:03, Patrik Jakobsson wrote:
>> CVE-2021-42327 was fixed by:
>>
>> commit f23750b5b3d98653b31d4469592935ef6364ad67
>> Author: Thelford Williams <tdwilliamsiv at gmail.com>
>> Date:   Wed Oct 13 16:04:13 2021 -0400
>>
>>     drm/amdgpu: fix out of bounds write
>>
>> but amdgpu_dm_debugfs.c contains more of the same issue so fix the
>> remaining ones.
>>
>> Fixes: 918698d5c2b5 ("drm/amd/display: Return the number of bytes parsed than allocated")
>> Signed-off-by: Patrik Jakobsson <pjakobsson at suse.de>
>> ---
>>  .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c    | 16 ++++++++--------
>>  1 file changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>> index 1a68a674913c..33bdf15febc6 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>> @@ -491,7 +491,7 @@ static ssize_t dp_phy_settings_write(struct file *f, const char __user *buf,
>>  	if (!wr_buf)
>>  		return -ENOSPC;
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  					   (long *)param, buf,
>>  					   max_param_num,
>>  					   &param_nums)) {
>> @@ -643,7 +643,7 @@ static ssize_t dp_phy_test_pattern_debugfs_write(struct file *f, const char __us
>>  	if (!wr_buf)
>>  		return -ENOSPC;
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  					   (long *)param, buf,
>>  					   max_param_num,
>>  					   &param_nums)) {
>> @@ -918,7 +918,7 @@ static ssize_t dp_dsc_passthrough_set(struct file *f, const char __user *buf,
>>  		return -ENOSPC;
>>  	}
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  					   &param, buf,
>>  					   max_param_num,
>>  					   &param_nums)) {
>> @@ -1215,7 +1215,7 @@ static ssize_t trigger_hotplug(struct file *f, const char __user *buf,
>>  		return -ENOSPC;
>>  	}
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  						(long *)param, buf,
>>  						max_param_num,
>>  						&param_nums)) {
>> @@ -1400,7 +1400,7 @@ static ssize_t dp_dsc_clock_en_write(struct file *f, const char __user *buf,
>>  		return -ENOSPC;
>>  	}
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  					    (long *)param, buf,
>>  					    max_param_num,
>>  					    &param_nums)) {
>> @@ -1585,7 +1585,7 @@ static ssize_t dp_dsc_slice_width_write(struct file *f, const char __user *buf,
>>  		return -ENOSPC;
>>  	}
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  					    (long *)param, buf,
>>  					    max_param_num,
>>  					    &param_nums)) {
>> @@ -1770,7 +1770,7 @@ static ssize_t dp_dsc_slice_height_write(struct file *f, const char __user *buf,
>>  		return -ENOSPC;
>>  	}
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  					    (long *)param, buf,
>>  					    max_param_num,
>>  					    &param_nums)) {
>> @@ -1948,7 +1948,7 @@ static ssize_t dp_dsc_bits_per_pixel_write(struct file *f, const char __user *bu
>>  		return -ENOSPC;
>>  	}
>>  
>> -	if (parse_write_buffer_into_params(wr_buf, size,
>> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
>>  					    (long *)param, buf,
>>  					    max_param_num,
>>  					    &param_nums)) {
>>
> 
> 
> Thanks. This looks good but you seem to be missing another
> instance of this in dp_max_bpc_write.
> 

This patch is
Reviewed-by: Harry Wentland <harry.wentland at amd.com>

I'll send a follow-up for dp_max_bpc_write.

Harry

> We'll also want to Linus's suggestion in [1] but I can post
> another patch for that.
> 
> https://lkml.org/lkml/2021/10/26/993>> 
> Harry
>