dany/pdfio
1
0
Fork 0
mirror of https://github.com/michaelrsweet/pdfio.git synced 2025-07-19 07:19:58 +02:00
Code Issues Packages Projects Releases Wiki Activity

Need object when reading/writing encrypted PDFs (to decrypt/encrypt strings),

Browse Source 
RC4 writing is now working, AES-128 needs work, AES-256 hasn't been done yet.
This commit is contained in:
Michael R Sweet
2021-10-23 18:08:16 -04:00
parent 3af39d5d1f
commit dd56317635
8 changed files with 175 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files

119
pdfio-value.c
View File

@ -194,6 +194,7 @@ _pdfioValueDelete(_pdfio_value_t *v) // I - Value
_pdfio_value_t * // O - Value or `NULL` on error/EOF
_pdfioValueRead(pdfio_file_t *pdf, // I - PDF file
pdfio_obj_t *obj, // I - Object, if any
_pdfio_token_t *tb, // I - Token buffer/stack
_pdfio_value_t *v) // I - Value
{
@ -216,7 +217,8 @@ _pdfioValueRead(pdfio_file_t *pdf, // I - PDF file
#endif // DEBUG
PDFIO_DEBUG("_pdfioValueRead(pdf=%p, v=%p)\n", pdf, v);
PDFIO_DEBUG("_pdfioValueRead(pdf=%p, obj=%p, v=%p)\n", pdf, obj, v);
(void)obj; // TODO: Implement decryption
if (!_pdfioTokenGet(tb, token, sizeof(token)))
return (NULL);
@ -225,14 +227,14 @@ _pdfioValueRead(pdfio_file_t *pdf, // I - PDF file
{
// Start of array
v->type = PDFIO_VALTYPE_ARRAY;
if ((v->value.array = _pdfioArrayRead(pdf, tb)) == NULL)
if ((v->value.array = _pdfioArrayRead(pdf, obj, tb)) == NULL)
return (NULL);
}
else if (!strcmp(token, "<<"))
{
// Start of dictionary
v->type = PDFIO_VALTYPE_DICT;
if ((v->value.dict = _pdfioDictRead(pdf, tb)) == NULL)
if ((v->value.dict = _pdfioDictRead(pdf, obj, tb)) == NULL)
return (NULL);
}
else if (!strncmp(token, "(D:", 3))
@ -474,6 +476,7 @@ _pdfioValueRead(pdfio_file_t *pdf, // I - PDF file
bool // O - `true` on success, `false` on failure
_pdfioValueWrite(pdfio_file_t *pdf, // I - PDF file
pdfio_obj_t *obj, // I - Object, if any
_pdfio_value_t *v, // I - Value
off_t *length)// O - Offset to /Length value, if any
{
@ -483,23 +486,47 @@ _pdfioValueWrite(pdfio_file_t *pdf, // I - PDF file
return (false);
case PDFIO_VALTYPE_ARRAY :
return (_pdfioArrayWrite(v->value.array));
return (_pdfioArrayWrite(v->value.array, obj));
case PDFIO_VALTYPE_BINARY :
{
size_t i; // Looping var
unsigned char *dataptr; // Pointer into data
size_t databytes; // Bytes to write
uint8_t temp[32768], // Temporary buffer for encryption
*dataptr; // Pointer into data
if (obj && pdf->encryption)
{
// Write encrypted string...
_pdfio_crypto_ctx_t ctx; // Encryption context
_pdfio_crypto_cb_t cb; // Encryption callback
size_t ivlen; // Number of initialization vector bytes
if (v->value.binary.datalen > (sizeof(temp) - 32))
{
_pdfioFileError(pdf, "Unable to write encrypted binary string - too long.");
return (false);
}
cb = _pdfioCryptoMakeWriter(pdf, obj, &ctx, temp, &ivlen);
databytes = (cb)(&ctx, temp + ivlen, v->value.binary.data, v->value.binary.datalen) + ivlen;
dataptr = temp;
}
else
{
dataptr = v->value.binary.data;
databytes = v->value.binary.datalen;
}
if (!_pdfioFilePuts(pdf, "<"))
return (false);
for (i = v->value.binary.datalen, dataptr = v->value.binary.data; i > 1; i -= 2, dataptr += 2)
for (; databytes > 1; databytes -= 2, dataptr += 2)
{
if (!_pdfioFilePrintf(pdf, "%02X%02X", dataptr[0], dataptr[1]))
return (false);
}
if (i > 0)
if (databytes > 0)
return (_pdfioFilePrintf(pdf, "%02X>", dataptr[0]));
else
return (_pdfioFilePuts(pdf, ">"));
@ -514,6 +541,7 @@ _pdfioValueWrite(pdfio_file_t *pdf, // I - PDF file
case PDFIO_VALTYPE_DATE :
{
struct tm date; // Date values
char datestr[32]; // Formatted date value
#ifdef _WIN32
gmtime_s(&date, &v->value.date);
@ -521,11 +549,45 @@ _pdfioValueWrite(pdfio_file_t *pdf, // I - PDF file
gmtime_r(&v->value.date, &date);
#endif // _WIN32
return (_pdfioFilePrintf(pdf, "(D:%04d%02d%02d%02d%02d%02dZ)", date.tm_year + 1900, date.tm_mon + 1, date.tm_mday, date.tm_hour, date.tm_min, date.tm_sec));
snprintf(datestr, sizeof(datestr), "D:%04d%02d%02d%02d%02d%02dZ", date.tm_year + 1900, date.tm_mon + 1, date.tm_mday, date.tm_hour, date.tm_min, date.tm_sec);
if (obj && pdf->encryption)
{
// Write encrypted string...
uint8_t temp[32768], // Encrypted bytes
*tempptr; // Pointer into encrypted bytes
_pdfio_crypto_ctx_t ctx; // Encryption context
_pdfio_crypto_cb_t cb; // Encryption callback
size_t len = strlen(datestr),
// Length of value
ivlen, // Number of initialization vector bytes
tempbytes; // Number of output bytes
cb = _pdfioCryptoMakeWriter(pdf, obj, &ctx, temp, &ivlen);
tempbytes = (cb)(&ctx, temp + ivlen, (const uint8_t *)datestr, len) + ivlen;
if (!_pdfioFilePuts(pdf, "<"))
return (false);
for (tempptr = temp; tempbytes > 1; tempbytes -= 2, tempptr += 2)
{
if (!_pdfioFilePrintf(pdf, "%02X%02X", tempptr[0], tempptr[1]))
return (false);
}
if (tempbytes > 0)
return (_pdfioFilePrintf(pdf, "%02X>", *tempptr));
else
return (_pdfioFilePuts(pdf, ">"));
}
else
{
return (_pdfioFilePrintf(pdf, "(%s)", datestr));
}
}
case PDFIO_VALTYPE_DICT :
return (_pdfioDictWrite(v->value.dict, length));
return (_pdfioDictWrite(v->value.dict, obj, length));
case PDFIO_VALTYPE_INDIRECT :
return (_pdfioFilePrintf(pdf, " %lu %u R", (unsigned long)v->value.indirect.number, v->value.indirect.generation));
@ -540,7 +602,44 @@ _pdfioValueWrite(pdfio_file_t *pdf, // I - PDF file
return (_pdfioFilePrintf(pdf, " %g", v->value.number));
case PDFIO_VALTYPE_STRING :
if (obj && pdf->encryption)
{
// Write encrypted string...
uint8_t temp[32768], // Encrypted bytes
*tempptr; // Pointer into encrypted bytes
_pdfio_crypto_ctx_t ctx; // Encryption context
_pdfio_crypto_cb_t cb; // Encryption callback
size_t len = strlen(v->value.string),
// Length of value
ivlen, // Number of initialization vector bytes
tempbytes; // Number of output bytes
if (len > (sizeof(temp) - 32))
{
_pdfioFileError(pdf, "Unable to write encrypted string - too long.");
return (false);
}
cb = _pdfioCryptoMakeWriter(pdf, obj, &ctx, temp, &ivlen);
tempbytes = (cb)(&ctx, temp + ivlen, (const uint8_t *)v->value.string, len) + ivlen;
if (!_pdfioFilePuts(pdf, "<"))
return (false);
for (tempptr = temp; tempbytes > 1; tempbytes -= 2, tempptr += 2)
{
if (!_pdfioFilePrintf(pdf, "%02X%02X", tempptr[0], tempptr[1]))
return (false);
}
if (tempbytes > 0)
return (_pdfioFilePrintf(pdf, "%02X>", *tempptr));
else
return (_pdfioFilePuts(pdf, ">"));
}
else
{
// Write unencrypted string...
const char *start, // Start of fragment
*end; // End of fragment