Re: [cryptopp-users] StringSource is using "new" operator. Should be deleting the memory or is it auto destroyed?
On Thu, Apr 27, 2023 at 1:57 PM Dwight Kulkarni wrote:
>
> Ok I think those RSA errors with memory are due to this pipelining, because
> the b64decode(..) b64encode(..) is called every where, and if I understand
> correctly, the string inside will be destroyed and I have to use the
> redirector. Can you confirm if you agree with this code change and my
> understanding of the problem ?
>
> Previous Code:
> std::string b64encode(std::string str)
> {
>using namespace CryptoPP;
>
> std::string encoded;
> StringSource(str, true,
> new Base64Encoder(
>new StringSink(encoded),
>false
> )
> );
> return encoded; //encoded will be destroyed once StringSource(..) goes
> out of scope
> }
This code is Ok.
The variable 'encoded' is not destroyed because it is a reference, and
not a pointer. 'encoded' is a stack variable. It will be destroyed
when the stack frame is cleaned up.
> New Code:
>
> std::string b64encode(std::string str)
> {
>using namespace CryptoPP;
>
> std::string encoded;
> Base64Encoder df(new CryptoPP::StringSink(encoded),false);
> StringSource(str, true, new Redirector(df) );
> return encoded; //encoded won't be destroyed
> }
This code is Ok, too. This code is effectively the same as the first
example. The Base64Encoder is now an automatic variable, and it will
be cleaned up when the destructor runs during stack cleanup.
The variable 'encoded' is not destroyed because it is a reference, and
not a pointer. 'encoded' is a stack variable. It will be destroyed
when the stack frame is cleaned up.
Your memory error lies elsewhere. Run Asan over your program.
Jeff
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Re: [cryptopp-users] StringSource is using "new" operator. Should be deleting the memory or is it auto destroyed?
Hi Jeff,
Ok I think those RSA errors with memory are due to this pipelining, because
the b64decode(..) b64encode(..) is called every where, and if I understand
correctly, the string inside will be destroyed and I have to use the
redirector. Can you confirm if you agree with this code change and my
understanding of the problem ?
*Previous Code:*
std::string b64encode(std::string str)
{
std::string encoded;
CryptoPP::StringSource(str, true,
new CryptoPP::Base64Encoder(
new CryptoPP::StringSink(encoded),
false
)
);
return encoded; //encoded will be destroyed once StringSource(..) goes out
of scope
}
*New Code:*
std::string b64encode(std::string str)
{
std::string encoded;
CryptoPP::Base64Encoder df(new CryptoPP::StringSink(encoded),false);
CryptoPP::StringSource(str, true, new Redirector(df) );
return encoded; //encoded won't be destroyed
}
based on this:
CCM< AES, TAG_SIZE >::Decryption d;
d.SetKeyWithIV( key, key.size(), iv, sizeof(iv) );
AuthenticatedDecryptionFilter df( d, new StringSink( recovered ) ); //
AuthenticatedDecryptionFilter // Cipher text includes the MAC tag
StringSource ss( cipher, true, new Redirector( df ) ); // StringSource //
If the object does not throw, here's the only // opportunity to check the
data's integrity
bool b = df.GetLastResult();
if( true == b ) { cout << recovered << endl; }
On Thursday, April 27, 2023 at 1:35:43 PM UTC-4 Jeffrey Walton wrote:
On Thu, Apr 27, 2023 at 1:31 PM Dwight Kulkarni
wrote:
>
> I note an example code sample for b64encode(..). I note that there are
"new" calls inside the constructor(..).
>
> The result is returned in the encoded string.
>
> Do I need to do anything to delete the memory from the new calls ?
>
> What happens to the memory in the variable "encoded", if the variable is
passed up to another function and the StringSink is destroyed.
>
> Should I make a copy of encoded and send it on to be safe ?
https://www.cryptopp.com/wiki/Pipelining#Ownership
Jeff
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Re: [cryptopp-users] StringSource is using "new" operator. Should be deleting the memory or is it auto destroyed?
On Thu, Apr 27, 2023 at 1:31 PM Dwight Kulkarni wrote: > > I note an example code sample for b64encode(..). I note that there are > "new" calls inside the constructor(..). > > The result is returned in the encoded string. > > Do I need to do anything to delete the memory from the new calls ? > > What happens to the memory in the variable "encoded", if the variable is > passed up to another function and the StringSink is destroyed. > > Should I make a copy of encoded and send it on to be safe ? https://www.cryptopp.com/wiki/Pipelining#Ownership Jeff -- You received this message because you are subscribed to the Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to cryptopp-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cryptopp-users/CAH8yC8%3DbpnWtPR-J4VBPWX0b1-amHU%3DPZcs65UMDtaGnHH_eLg%40mail.gmail.com.
