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ASN1: tweaks to tag decoding

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This commit is contained in:
terrafrost 2021-04-02 13:46:14 -05:00
parent b90c33200e
commit 95f597cfb3
1 changed files with 10 additions and 3 deletions
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13
phpseclib/File/ASN1.php
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@ -317,7 +317,7 @@ class File_ASN1
$current = array('start' => $start);
$type = ord($encoded[$encoded_pos++]);
$start++;
$startOffset = 1;
$constructed = ($type >> 5) & 1;
@ -327,13 +327,20 @@ class File_ASN1
// process septets (since the eighth bit is ignored, it's not an octet)
do {
$temp = ord($encoded[$encoded_pos++]);
$startOffset++;
$loop = $temp >> 7;
$tag <<= 7;
$tag |= $temp & 0x7F;
$start++;
$temp &= 0x7F;
// "bits 7 to 1 of the first subsequent octet shall not all be zero"
if ($startOffset == 2 && $temp == 0) {
return false;
}
$tag |= $temp;
} while ($loop);
}
$start+= $startOffset;
// Length, as discussed in paragraph 8.1.3 of X.690-0207.pdf#page=13
$length = ord($encoded[$encoded_pos++]);
$start++;