Re: [PATCH 1/3] libimaevm: Implement imaevm_create_ima_signature

[Stefan Berger <stefanb@linux.ibm.com>]

On 4/26/21 8:02 PM, Colin Walters wrote:
>
> On Tue, Apr 20, 2021, at 2:30 PM, Stefan Berger wrote:
>
>> + fd = open(filename, O_RDONLY);
> Missing O_CLOEXEC.


Will do.

>
>> +int imaevm_create_ima_signature(const char *filename, EVP_PKEY *pkey,
> It'd maximize flexibility for the caller to pass a file descriptor, and not a file name.


We could do this with a callback where the user implements the callback 
function and providers buffer, size of buffer, and eof indicator, and 
gets called for providing the data to hash. That would maybe be even 
more flexible..


>
>> +	if (statbuf.st_size > 0) {
>> +		addr = mmap(NULL, statbuf.st_size, PROT_READ, MAP_SHARED, fd, 0);
>> +		if (addr == MAP_FAILED) {
>> +			asprintf(error, "Failed to mmap file: %s", strerror(errno));
>> +			goto err_close;
>> +		}
>> +	}
> Tangentially related to this, I think we should consider doing the same optimization here:
> https://github.com/ostreedev/ostree/blob/36693f064c63dad550ebcfed33bf9b95806ddef9/src/libotutil/ot-fs-utils.c#L171
>
> Or alternatively, just have the caller provide a (mmap'd or copied-via-read()) buffer?
>
> Though clearly the most flexible is a streaming API.  But eh, I am not really concerned about that level of performance.


I think using a callback would allow for the streaming as well...

    Stefan