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opencloud/vendor/github.com/amoghe/go-crypt/crypt_r.go
2023-04-19 20:24:34 +02:00

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// +build linux
// Package crypt provides wrappers around functions available in crypt.h
//
// It wraps around the GNU specific extension (crypt_r) when it is available
// (i.e. where GOOS=linux). This makes the go function reentrant (and thus
// callable from concurrent goroutines).
package crypt
import (
"syscall"
"unsafe"
)
/*
#cgo LDFLAGS: -lcrypt
#define _GNU_SOURCE
#include <stdlib.h>
#include <string.h>
#include <crypt.h>
char *gnu_ext_crypt(char *pass, char *salt) {
char *enc = NULL;
char *ret = NULL;
struct crypt_data data;
data.initialized = 0;
enc = crypt_r(pass, salt, &data);
if(enc == NULL) {
return NULL;
}
ret = (char *)malloc(strlen(enc)+1); // for trailing null
strncpy(ret, enc, strlen(enc));
ret[strlen(enc)]= '\0'; // paranoid
return ret;
}
*/
import "C"
// Crypt provides a wrapper around the glibc crypt_r() function.
// For the meaning of the arguments, refer to the package README.
func Crypt(pass, salt string) (string, error) {
c_pass := C.CString(pass)
defer C.free(unsafe.Pointer(c_pass))
c_salt := C.CString(salt)
defer C.free(unsafe.Pointer(c_salt))
c_enc, err := C.gnu_ext_crypt(c_pass, c_salt)
if c_enc == nil {
return "", err
}
defer C.free(unsafe.Pointer(c_enc))
// From the crypt(3) man-page. Upon error, crypt_r writes an invalid
// hashed passphrase to the output field of their data argument, and
// crypt writes an invalid hash to its static storage area. This
// string will be shorter than 13 characters, will begin with a *,
// and will not compare equal to setting.
hash := C.GoString(c_enc)
if len(hash) > 0 && hash[0] == '*' {
// Make sure we acutally return an error, musl e.g. does not
// set errno in all cases here.
if err == nil {
err = syscall.EINVAL
}
return "", err
}
// Return nil error if the string is non-nil.
// As per the errno.h manpage, functions are allowed to set errno
// on success. Caller should ignore errno on success.
return hash, nil
}