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pgcrypto: Remove internal padding implementation

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Use the padding provided by OpenSSL instead of doing it ourselves.
The internal implementation was once applicable to the non-OpenSSL
code paths, but those have since been removed.  The padding algorithm
is still the same.

The OpenSSL padding implementation is stricter than the previous
internal one: Bad padding during decryption is now an error, and
encryption without padding now requires the input size to be a
multiple of the block size, otherwise it is also an error.
Previously, these cases silently proceeded, in spite of the
documentation saying otherwise.

Add some test cases about this, too.  (The test cases are in
rijndael.sql, but they apply to all encryption algorithms.)

Reviewed-by: Jacob Champion <pchampion@vmware.com>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/ba94c26b-0c58-c97e-7a44-f44e08b4cca2%40enterprisedb.com
This commit is contained in:
Peter Eisentraut
2022-03-22 08:51:05 +01:00
parent 9ca234bae7
commit f5576a21b0
6 changed files with 52 additions and 134 deletions
Download Patch File Download Diff File Expand all files Collapse all files

120
contrib/pgcrypto/px.c
View File

@ -44,7 +44,6 @@ static const struct error_desc px_err_list[] = {
{PXE_ERR_GENERIC, "Some PX error (not specified)"},
{PXE_NO_HASH, "No such hash algorithm"},
{PXE_NO_CIPHER, "No such cipher algorithm"},
{PXE_NOTBLOCKSIZE, "Data not a multiple of block size"},
{PXE_BAD_OPTION, "Unknown option"},
{PXE_BAD_FORMAT, "Badly formatted type"},
{PXE_KEY_TOO_BIG, "Key was too big"},
@ -221,129 +220,14 @@ static int
combo_encrypt(PX_Combo *cx, const uint8 *data, unsigned dlen,
uint8 *res, unsigned *rlen)
{
int err = 0;
uint8 *bbuf;
unsigned bs,
bpos,
i,
pad;
PX_Cipher *c = cx->cipher;
bbuf = NULL;
bs = px_cipher_block_size(c);
/* encrypt */
if (bs > 1)
{
bbuf = palloc(bs * 4);
bpos = dlen % bs;
*rlen = dlen - bpos;
memcpy(bbuf, data + *rlen, bpos);
/* encrypt full-block data */
if (*rlen)
{
err = px_cipher_encrypt(c, data, *rlen, res);
if (err)
goto out;
}
/* bbuf has now bpos bytes of stuff */
if (cx->padding)
{
pad = bs - (bpos % bs);
for (i = 0; i < pad; i++)
bbuf[bpos++] = pad;
}
else if (bpos % bs)
{
/* ERROR? */
pad = bs - (bpos % bs);
for (i = 0; i < pad; i++)
bbuf[bpos++] = 0;
}
/* encrypt the rest - pad */
if (bpos)
{
err = px_cipher_encrypt(c, bbuf, bpos, res + *rlen);
*rlen += bpos;
}
}
else
{
/* stream cipher/mode - no pad needed */
err = px_cipher_encrypt(c, data, dlen, res);
if (err)
goto out;
*rlen = dlen;
}
out:
if (bbuf)
pfree(bbuf);
return err;
return px_cipher_encrypt(cx->cipher, cx->padding, data, dlen, res, rlen);
}
static int
combo_decrypt(PX_Combo *cx, const uint8 *data, unsigned dlen,
uint8 *res, unsigned *rlen)
{
int err = 0;
unsigned bs,
i,
pad;
unsigned pad_ok;
PX_Cipher *c = cx->cipher;
/* decide whether zero-length input is allowed */
if (dlen == 0)
{
/* with padding, empty ciphertext is not allowed */
if (cx->padding)
return PXE_DECRYPT_FAILED;
/* without padding, report empty result */
*rlen = 0;
return 0;
}
bs = px_cipher_block_size(c);
if (bs > 1 && (dlen % bs) != 0)
goto block_error;
/* decrypt */
*rlen = dlen;
err = px_cipher_decrypt(c, data, dlen, res);
if (err)
return err;
/* unpad */
if (bs > 1 && cx->padding)
{
pad = res[*rlen - 1];
pad_ok = 0;
if (pad > 0 && pad <= bs && pad <= *rlen)
{
pad_ok = 1;
for (i = *rlen - pad; i < *rlen; i++)
if (res[i] != pad)
{
pad_ok = 0;
break;
}
}
if (pad_ok)
*rlen -= pad;
}
return 0;
block_error:
return PXE_NOTBLOCKSIZE;
return px_cipher_decrypt(cx->cipher, cx->padding, data, dlen, res, rlen);
}
static void