OpenSSL RSA_verify() Access Violation
lazarus / 62-General

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Fibonacci · 2024-10-07 08:57

I guess Im doing something wrong and I dont see it

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses 
SysUtils,  Classes,  openssl; const  //LIBCRYPTO = 'libcrypto.dll'; 
//LIBCRYPTO = 'libcrypto-1_1-x64.dll';  LIBCRYPTO =
'libcrypto-3-x64.dll'; function RSA_verify(typ:integer; m: PByte;
m_length: cardinal; sigbuf: PByte; siglen: cardinal; rsa: PRSA):
integer; cdecl; external LIBCRYPTO; function loadpub(path: string):
PRSA;var  bio: PBIO;  evp: PEVP_PKEY;begin  result := nil;  bio :=
BIO_new_file(@path[1], 'r');  if bio = nil then exit;  evp := nil; 
//evp := EvpPkeyNew;  result := PEM_read_bio_PUBKEY(bio, evp, nil,
nil);end; var  r: integer;  message, signature: string;  rsa: PRSA; 
f: PRSA_METHOD; begin  //if not InitSSLInterface then begin  //if not
InitSSLInterface('libssl.dll', 'libcrypto.dll') then begin  //if not
InitSSLInterface('libssl-1_1-x64.dll', 'libcrypto-1_1-x64.dll') then
begin  if not InitSSLInterface('libssl-3-x64.dll',
'libcrypto-3-x64.dll') then begin    writeln('init ssl failed');   
readln;    halt;  end;   message := 'message';  signature :=
'signature';   //rsa := loadpub('public_key.pem');  rsa :=
loadpub('public_key_sign.pem');  writeln('rsa = ',
inttohex(ptrint(rsa)));   try    // Access violation reading from
address $0000000000000060.    f := RSA_get_method(rsa);    r :=
f^.rsa_verify(672{NID_sha256}, @message[1], length(message),
@signature[1], length(signature), rsa);     // Access violation
reading from address $0000000000000060.    //r :=
RSA_verify(672{NID_sha256}, @message[1], length(message),
@signature[1], length(signature), rsa);  except    on E: Exception do
writeln(e.Message);  end;   readln;end.

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Fibonacci · 2024-10-07 10:11

Solved using mormot, in case anyone interested:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses 
SysUtils,  Classes,  mormot.crypt.rsa,  mormot.crypt.secure, 
mormot.crypt.core; const  _PEM_SIGNATURE_FILE =
'D:\...\public_key_sign.pem';  _MESSAGE_FILE       =
'D:\...\plaintext.txt';  _SIGNATURE_FILE     =
'D:\...\rsa_signature.txt'; function loadfile(path: string):
string;var  m: TMemoryStream;begin  if not FileExists(path) then
exit('');  m := TMemoryStream.Create;  try    m.LoadFromFile(path);  
setlength(result, m.Size);    m.Read(result[1], m.Size);  finally    
m.Free;  end;end;  var  k: TRsa;  message, signature: string;  hash:
TSha256Digest; begin  k := TRsa.Create;  try   
k.LoadFromPublicKeyPem(loadfile(_PEM_SIGNATURE_FILE));     message :=
loadfile(_MESSAGE_FILE);    hash := Sha256Digest(message);    
signature := loadfile(_SIGNATURE_FILE);     writeln('verify 1 = ',
k.Verify(@hash[0], @signature[1], hfSHA256, length(signature)));   
writeln('verify 2 = ', k.Verify(@hash[0], hfSHA256, signature)); 
finally       k.Free;  end;   readln;end.

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Thaddy · 2024-10-07 12:26

it failed because the structures are not initialized.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   rsa:
PRSA;  f: PRSA_METHOD;

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Fibonacci · 2024-10-07 12:32

Quote from: Thaddy on October 07, 2024, 02:26:17 pmit failed because
the structures are not initialized.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   rsa:
PRSA;  f: PRSA_METHOD;
PRSA type is
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i PRSA =
SslPtr;SslPtr = Pointer;
PRSA_METHOD is a record

There is nothing to initialize

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Thaddy · 2024-10-07 13:11

The P suggests a pointer type. If not try {$packrecords C}
but I seem to remember the are pointers to a BIO struct and a pointer
to an EVP_KEY_<x> struct.

[edit]
I checked. They are pointers. see openssl.pas line 177