[PATCH] apparmor: replace decompress_zstd() prototype with its entity

[John Johansen]

On 7/15/26 16:05, Tetsuo Handa wrote:
> Thank you. Please send to linux-next tree via apparmor tree, for
> syzbot won't be able to test linux-next tree due to this build failure.
> 
done, thanks Tetsuo


> On 2026/07/15 21:14, Georgia Garcia wrote:
>> Hello,
>>
>> On Sun, 2026-07-12 at 19:17 +0900, Tetsuo Handa wrote:
>>> Fix "undefined symbol: decompress_zstd" error caused by decompress_zstd()
>>> being guarded by CONFIG_SECURITY_APPARMOR_EXPORT_BINARY=y.
>>>
>>
>> Acked-by: Georgia Garcia <georgia.garcia at canonical.com>
>>
>>> Reported-by: syzbot+1f14a35d0c73d31555e4 at syzkaller.appspotmail.com
>>> Closes: https://syzkaller.appspot.com/bug?extid=1f14a35d0c73d31555e4
>>> Fixes: 17b5758bf35c ("apparmor: Initial support for compressed policies")
>>> Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
>>> ---
>>>   security/apparmor/apparmorfs.c | 72 +++++++++++++++++-----------------
>>>   1 file changed, 36 insertions(+), 36 deletions(-)
>>>
>>> diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
>>> index 2ae9ab94a5a91..152c7967ff1ba 100644
>>> --- a/security/apparmor/apparmorfs.c
>>> +++ b/security/apparmor/apparmorfs.c
>>> @@ -483,7 +483,42 @@ static struct aa_loaddata *aa_simple_write_to_buffer(const char __user *userbuf,
>>>   
>>>   	return data;
>>>   }
>>> -static int decompress_zstd(char *src, size_t slen, char *dst, size_t dlen);
>>> +
>>> +static int decompress_zstd(char *src, size_t slen, char *dst, size_t dlen)
>>> +{
>>> +	if (slen < dlen) {
>>> +		const size_t wksp_len = zstd_dctx_workspace_bound();
>>> +		zstd_dctx *ctx;
>>> +		void *wksp;
>>> +		size_t out_len;
>>> +		int ret = 0;
>>> +
>>> +		wksp = kvzalloc(wksp_len, GFP_KERNEL);
>>> +		if (!wksp) {
>>> +			ret = -ENOMEM;
>>> +			goto cleanup;
>>> +		}
>>> +		ctx = zstd_init_dctx(wksp, wksp_len);
>>> +		if (ctx == NULL) {
>>> +			ret = -ENOMEM;
>>> +			goto cleanup;
>>> +		}
>>> +		out_len = zstd_decompress_dctx(ctx, dst, dlen, src, slen);
>>> +		if (zstd_is_error(out_len)) {
>>> +			ret = -EINVAL;
>>> +			goto cleanup;
>>> +		}
>>> +cleanup:
>>> +		kvfree(wksp);
>>> +		return ret;
>>> +	}
>>> +
>>> +	if (dlen < slen)
>>> +		return -EINVAL;
>>> +	memcpy(dst, src, slen);
>>> +	return 0;
>>> +}
>>> +
>>>   /**
>>>    * aa_get_data_from_compressed - common routine for getting compressed policy
>>>    * from user and get both compressed and uncompressed version.
>>> @@ -1517,41 +1552,6 @@ SEQ_RAWDATA_FOPS(revision);
>>>   SEQ_RAWDATA_FOPS(hash);
>>>   SEQ_RAWDATA_FOPS(compressed_size);
>>>   
>>> -static int decompress_zstd(char *src, size_t slen, char *dst, size_t dlen)
>>> -{
>>> -	if (slen < dlen) {
>>> -		const size_t wksp_len = zstd_dctx_workspace_bound();
>>> -		zstd_dctx *ctx;
>>> -		void *wksp;
>>> -		size_t out_len;
>>> -		int ret = 0;
>>> -
>>> -		wksp = kvzalloc(wksp_len, GFP_KERNEL);
>>> -		if (!wksp) {
>>> -			ret = -ENOMEM;
>>> -			goto cleanup;
>>> -		}
>>> -		ctx = zstd_init_dctx(wksp, wksp_len);
>>> -		if (ctx == NULL) {
>>> -			ret = -ENOMEM;
>>> -			goto cleanup;
>>> -		}
>>> -		out_len = zstd_decompress_dctx(ctx, dst, dlen, src, slen);
>>> -		if (zstd_is_error(out_len)) {
>>> -			ret = -EINVAL;
>>> -			goto cleanup;
>>> -		}
>>> -cleanup:
>>> -		kvfree(wksp);
>>> -		return ret;
>>> -	}
>>> -
>>> -	if (dlen < slen)
>>> -		return -EINVAL;
>>> -	memcpy(dst, src, slen);
>>> -	return 0;
>>> -}
>>> -
>>>   static ssize_t rawdata_read(struct file *file, char __user *buf, size_t size,
>>>   			    loff_t *ppos)
>>>   {
>>
>