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authorDavid Kalnischkies <david@kalnischkies.de>2020-12-03 10:41:43 +0100
committerDavid Kalnischkies <david@kalnischkies.de>2021-02-03 17:36:45 +0100
commit10f13938bbf1474451fadcd62e1c31c4b5f5b3d7 (patch)
treedcf18bfced7c4447eb5ed212f8026a2df0354335
parent03790b071d6a97374a03af36eda5698a143300b0 (diff)
Fix incorrect base64 encoding due to int promotion
For \xff and friends with the highest bit set and hence being a negative value on signed char systems the wrong encoding is produced as we run into undefined behaviour accessing negative array indexes. We can avoid this problem simply by using an unsigned data type.
-rw-r--r--apt-pkg/contrib/strutl.cc2
-rw-r--r--test/libapt/strutil_test.cc4
2 files changed, 5 insertions, 1 deletions
diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
index bd4856526..826b21478 100644
--- a/apt-pkg/contrib/strutl.cc
+++ b/apt-pkg/contrib/strutl.cc
@@ -597,7 +597,7 @@ string Base64Encode(const string &S)
base64. */
for (string::const_iterator I = S.begin(); I < S.end(); I += 3)
{
- char Bits[3] = {0,0,0};
+ uint8_t Bits[3] = {0,0,0};
Bits[0] = I[0];
if (I + 1 < S.end())
Bits[1] = I[1];
diff --git a/test/libapt/strutil_test.cc b/test/libapt/strutil_test.cc
index 349946b5f..f101d72cf 100644
--- a/test/libapt/strutil_test.cc
+++ b/test/libapt/strutil_test.cc
@@ -167,6 +167,10 @@ TEST(StrUtilTest,Base64Encode)
EXPECT_EQ("ZS4=", Base64Encode("e."));
EXPECT_EQ("Lg==", Base64Encode("."));
EXPECT_EQ("", Base64Encode(""));
+ EXPECT_EQ("IA==", Base64Encode("\x20"));
+ EXPECT_EQ("/w==", Base64Encode("\xff"));
+ EXPECT_EQ("/A==", Base64Encode("\xfc"));
+ EXPECT_EQ("//8=", Base64Encode("\xff\xff"));
}
static void ReadMessagesTestWithNewLine(char const * const nl, char const * const ab)
{