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Fix error detection in 'base64Decode()'

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Fixed a bug in initialization of 'base64DecodeChars' variable.
Currently decoder do not fail on invalid Base64 strings.
Added test-case to verify the fix.

Also have made 'base64DecodeChars' to be computed at compile time.
And added a test case to encode/decode string with non-printable charactes.
This commit is contained in:
Alexey Novikov 2021-10-17 11:51:33 +04:00
parent 130284b850
commit 64a3b045c1
2 changed files with 27 additions and 8 deletions
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18
src/libutil/util.cc
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@ -1436,8 +1436,7 @@ std::string filterANSIEscapes(const std::string & s, bool filterAll, unsigned in
}
static char base64Chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static std::array<char, 256> base64DecodeChars;
constexpr char base64Chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
string base64Encode(std::string_view s)
{
@ -1462,12 +1461,15 @@ string base64Encode(std::string_view s)
string base64Decode(std::string_view s)
{
static std::once_flag flag;
std::call_once(flag, [](){
base64DecodeChars = { (char)-1 };
constexpr char npos = -1;
constexpr std::array<char, 256> base64DecodeChars = [&]() {
std::array<char, 256> result{};
for (auto& c : result)
c = npos;
for (int i = 0; i < 64; i++)
base64DecodeChars[(int) base64Chars[i]] = i;
});
result[base64Chars[i]] = i;
return result;
}();
string res;
unsigned int d = 0, bits = 0;
@ -1477,7 +1479,7 @@ string base64Decode(std::string_view s)
if (c == '\n') continue;
char digit = base64DecodeChars[(unsigned char) c];
if (digit == -1)
if (digit == npos)
throw Error("invalid character in Base64 string: '%c'", c);
bits += 6;