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authorDavid Kalnischkies <david@kalnischkies.de>2016-07-26 00:01:50 +0200
committerJulian Andres Klode <jak@debian.org>2016-08-31 14:16:10 +0200
commite6b75e6e89a72edfc7d71ea0269f3ad8041da0b2 (patch)
treec69dabd7145c47583626b6f57a74af11e2789c79 /methods/rred.cc
parent689857bec8c01a222d2ce0369a13994920c9155b (diff)
verify hash of input file in rred
We read the entire input file we want to patch anyhow, so we can also calculate the hash for that file and compare it with what he had expected it to be. Note that this isn't really a security improvement as a) the file we patch is trusted & b) if the input is incorrect, the result will hardly be matching, so this is just for failing slightly earlier with a more relevant error message (althrough, in terms of rred its ignored and complete download attempt instead). (cherry picked from commit 6e71ec6fcdcaa926c98fa58cd4af38e42556df15)
Diffstat (limited to 'methods/rred.cc')
-rw-r--r--methods/rred.cc57
1 files changed, 41 insertions, 16 deletions
diff --git a/methods/rred.cc b/methods/rred.cc
index 79ab8cb52..8573c3922 100644
--- a/methods/rred.cc
+++ b/methods/rred.cc
@@ -336,26 +336,30 @@ class Patch {
FileChanges filechanges;
MemBlock add_text;
- static bool retry_fwrite(char *b, size_t l, FileFd &f, Hashes *hash)
+ static bool retry_fwrite(char *b, size_t l, FileFd &f, Hashes * const start_hash, Hashes * const end_hash = nullptr)
{
if (f.Write(b, l) == false)
return false;
- if (hash)
- hash->Add((unsigned char*)b, l);
+ if (start_hash)
+ start_hash->Add((unsigned char*)b, l);
+ if (end_hash)
+ end_hash->Add((unsigned char*)b, l);
return true;
}
- static void dump_rest(FileFd &o, FileFd &i, Hashes *hash)
+ static void dump_rest(FileFd &o, FileFd &i,
+ Hashes * const start_hash, Hashes * const end_hash)
{
char buffer[BLOCK_SIZE];
unsigned long long l = 0;
while (i.Read(buffer, sizeof(buffer), &l)) {
- if (l ==0 || !retry_fwrite(buffer, l, o, hash))
+ if (l ==0 || !retry_fwrite(buffer, l, o, start_hash, end_hash))
break;
}
}
- static void dump_lines(FileFd &o, FileFd &i, size_t n, Hashes *hash)
+ static void dump_lines(FileFd &o, FileFd &i, size_t n,
+ Hashes * const start_hash, Hashes * const end_hash)
{
char buffer[BLOCK_SIZE];
while (n > 0) {
@@ -364,11 +368,11 @@ class Patch {
size_t const l = strlen(buffer);
if (l == 0 || buffer[l-1] == '\n')
n--;
- retry_fwrite(buffer, l, o, hash);
+ retry_fwrite(buffer, l, o, start_hash, end_hash);
}
}
- static void skip_lines(FileFd &i, int n)
+ static void skip_lines(FileFd &i, int n, Hashes * const start_hash)
{
char buffer[BLOCK_SIZE];
while (n > 0) {
@@ -377,6 +381,8 @@ class Patch {
size_t const l = strlen(buffer);
if (l == 0 || buffer[l-1] == '\n')
n--;
+ if (start_hash)
+ start_hash->Add((unsigned char*)buffer, l);
}
}
@@ -526,15 +532,16 @@ class Patch {
}
}
- void apply_against_file(FileFd &out, FileFd &in, Hashes *hash = NULL)
+ void apply_against_file(FileFd &out, FileFd &in,
+ Hashes * const start_hash = nullptr, Hashes * const end_hash = nullptr)
{
std::list<struct Change>::iterator ch;
for (ch = filechanges.begin(); ch != filechanges.end(); ++ch) {
- dump_lines(out, in, ch->offset, hash);
- skip_lines(in, ch->del_cnt);
- dump_mem(out, ch->add, ch->add_len, hash);
+ dump_lines(out, in, ch->offset, start_hash, end_hash);
+ skip_lines(in, ch->del_cnt, start_hash);
+ dump_mem(out, ch->add, ch->add_len, end_hash);
}
- dump_rest(out, in, hash);
+ dump_rest(out, in, start_hash, end_hash);
out.Flush();
}
};
@@ -582,6 +589,16 @@ class RredMethod : public aptMethod {
std::vector<PDiffFile> patchfiles;
Patch patch;
+ HashStringList StartHashes;
+ for (char const * const * type = HashString::SupportedHashes(); *type != nullptr; ++type)
+ {
+ std::string tagname;
+ strprintf(tagname, "Start-%s-Hash", *type);
+ std::string const hashsum = LookupTag(Message, tagname.c_str());
+ if (hashsum.empty() == false)
+ StartHashes.push_back(HashString(*type, hashsum));
+ }
+
if (FileExists(Path + ".ed") == true)
{
HashStringList const ExpectedHashes = ReadExpectedHashesForPatch(0, Message);
@@ -654,8 +671,16 @@ class RredMethod : public aptMethod {
return _error->Error("Failed to open out %s", Itm->DestFile.c_str());
}
- Hashes hash(Itm->ExpectedHashes);
- patch.apply_against_file(out, inp, &hash);
+ Hashes end_hash(Itm->ExpectedHashes);
+ if (StartHashes.usable())
+ {
+ Hashes start_hash(StartHashes);
+ patch.apply_against_file(out, inp, &start_hash, &end_hash);
+ if (start_hash.GetHashStringList() != StartHashes)
+ _error->Error("The input file hadn't the expected hash!");
+ }
+ else
+ patch.apply_against_file(out, inp, nullptr, &end_hash);
out.Close();
inp.Close();
@@ -686,7 +711,7 @@ class RredMethod : public aptMethod {
Res.LastModified = bufbase.st_mtime;
Res.Size = bufbase.st_size;
- Res.TakeHashes(hash);
+ Res.TakeHashes(end_hash);
URIDone(Res);
return true;