diff options
| author | Julian Andres Klode <jak@debian.org> | 2016-08-31 17:01:04 +0200 |
|---|---|---|
| committer | Julian Andres Klode <jak@debian.org> | 2016-10-05 21:53:38 +0200 |
| commit | 43ed244f35c0bbd3bec2dae0d5e71d98f6314d23 (patch) | |
| tree | 79230ea1e345407cab6a72cbfee23a170f75517e /apt-pkg | |
| parent | b9cddcfb31dd6da49fcd470aaa484eafcfc779ae (diff) | |
TagFile: Fix off-by-one errors in comment stripping
Adding 1 to the value of d->End - current makes restLength one byte
too long: If we pass memchr(current, ..., restLength) has thus
undefined behavior.
Also, reading the value of current has undefined behavior if
current >= d->End, not only for current > d->End:
Consider a string of length 1, that is d->End = d->Current + 1.
We can only read at d->Current + 0, but d->Current + 1 is beyond
the end of the string.
This probably caused several inexplicable build failures on hurd-i386
in the past, and just now caused a build failure on Ubuntu's amd64
builder.
Reported-By: valgrind
(cherry picked from commit 923c592ceb6014b31ec751b97b3ed659fa3e88ae)
Diffstat (limited to 'apt-pkg')
| -rw-r--r-- | apt-pkg/tagfile.cc | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/apt-pkg/tagfile.cc b/apt-pkg/tagfile.cc index 3a3a3a04a..69148e08b 100644 --- a/apt-pkg/tagfile.cc +++ b/apt-pkg/tagfile.cc @@ -300,7 +300,7 @@ static void RemoveCommentsFromBuffer(pkgTagFilePrivate * const d) std::vector<std::pair<char*, size_t>> good_parts; while (current <= d->End) { - size_t const restLength = (d->End - current) + 1; + size_t const restLength = (d->End - current); if (d->isCommentedLine == false) { current = static_cast<char*>(memchr(current, '#', restLength)); @@ -335,7 +335,7 @@ static void RemoveCommentsFromBuffer(pkgTagFilePrivate * const d) } ++current; // is the next line a comment, too? - if (current > d->End || *current != '#') + if (current >= d->End || *current != '#') { d->chunks.emplace_back(false, (current - bad_start)); good_start = current; |