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authorDavid Kalnischkies <david@kalnischkies.de>2014-10-23 16:54:00 +0200
committerDavid Kalnischkies <david@kalnischkies.de>2014-10-24 23:54:59 +0200
commit23397c9d7d4d455461176600bb45c81185493504 (patch)
treed31bba61b1c04aa66f9a17dca19127dd94d8f65d /apt-pkg/contrib
parent10e100e59a96ea7b6834a139beab5d9d70180633 (diff)
promote filesize to a hashstring
It is a very simple hashstring, which is why it isn't contributing to the usability of a list of them, but it is also trivial to check and calculate, so it doesn't hurt checking it either as it can combined even with the simplest other hashes greatly complicate attacks on them as you suddenly need a same-size hash collision, which is usually a lot harder to achieve.
Diffstat (limited to 'apt-pkg/contrib')
-rw-r--r--apt-pkg/contrib/hashes.cc32
-rw-r--r--apt-pkg/contrib/hashes.h4
2 files changed, 29 insertions, 7 deletions
diff --git a/apt-pkg/contrib/hashes.cc b/apt-pkg/contrib/hashes.cc
index 417982343..55180c642 100644
--- a/apt-pkg/contrib/hashes.cc
+++ b/apt-pkg/contrib/hashes.cc
@@ -29,7 +29,7 @@
const char * HashString::_SupportedHashes[] =
{
- "SHA512", "SHA256", "SHA1", "MD5Sum", NULL
+ "SHA512", "SHA256", "SHA1", "MD5Sum", "Checksum-FileSize", NULL
};
HashString::HashString()
@@ -111,6 +111,8 @@ std::string HashString::GetHashForFile(std::string filename) const /*{{{*/
SHA512.AddFD(Fd);
fileHash = (std::string)SHA512.Result();
}
+ else if (strcasecmp(Type.c_str(), "Checksum-FileSize") == 0)
+ strprintf(fileHash, "%llu", Fd.FileSize());
Fd.Close();
return fileHash;
@@ -147,7 +149,13 @@ bool HashStringList::usable() const /*{{{*/
return false;
std::string const forcedType = _config->Find("Acquire::ForceHash", "");
if (forcedType.empty() == true)
- return true;
+ {
+ // FileSize alone isn't usable
+ for (std::vector<HashString>::const_iterator hs = list.begin(); hs != list.end(); ++hs)
+ if (hs->HashType() != "Checksum-FileSize")
+ return true;
+ return false;
+ }
return find(forcedType) != NULL;
}
/*}}}*/
@@ -201,6 +209,9 @@ bool HashStringList::VerifyFile(std::string filename) const /*{{{*/
HashString const * const hs = find(NULL);
if (hs == NULL || hs->VerifyFile(filename) == false)
return false;
+ HashString const * const hsf = find("Checksum-FileSize");
+ if (hsf != NULL && hsf->VerifyFile(filename) == false)
+ return false;
return true;
}
/*}}}*/
@@ -235,6 +246,14 @@ bool HashStringList::operator!=(HashStringList const &other) const
}
/*}}}*/
+// PrivateHashes /*{{{*/
+class PrivateHashes {
+public:
+ unsigned long long FileSize;
+
+ PrivateHashes() : FileSize(0) {}
+};
+ /*}}}*/
// Hashes::Add* - Add the contents of data or FD /*{{{*/
bool Hashes::Add(const unsigned char * const Data,unsigned long long const Size, unsigned int const Hashes)
{
@@ -254,6 +273,7 @@ bool Hashes::Add(const unsigned char * const Data,unsigned long long const Size,
#if __GNUC__ >= 4
#pragma GCC diagnostic pop
#endif
+ d->FileSize += Size;
return Res;
}
bool Hashes::AddFD(int const Fd,unsigned long long Size, unsigned int const Hashes)
@@ -314,15 +334,17 @@ HashStringList Hashes::GetHashStringList()
#if __GNUC__ >= 4
#pragma GCC diagnostic pop
#endif
+ std::string SizeStr;
+ strprintf(SizeStr, "%llu", d->FileSize);
+ hashes.push_back(HashString("Checksum-FileSize", SizeStr));
return hashes;
}
#if __GNUC__ >= 4
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
- #pragma GCC diagnostic ignored "-Wsuggest-attribute=const"
#endif
-Hashes::Hashes() {}
-Hashes::~Hashes() {}
+Hashes::Hashes() { d = new PrivateHashes(); }
+Hashes::~Hashes() { delete d; }
#if __GNUC__ >= 4
#pragma GCC diagnostic pop
#endif
diff --git a/apt-pkg/contrib/hashes.h b/apt-pkg/contrib/hashes.h
index caeba006d..e2e213855 100644
--- a/apt-pkg/contrib/hashes.h
+++ b/apt-pkg/contrib/hashes.h
@@ -161,10 +161,10 @@ class HashStringList
std::vector<HashString> list;
};
+class PrivateHashes;
class Hashes
{
- /** \brief dpointer placeholder */
- void *d;
+ PrivateHashes *d;
public:
/* those will disappear in the future as it is hard to add new ones this way.