nix-super/src/libstore/path-regex.hh
Robert Hensing f1b4663805 Disallow store path names that are . or .. (plus opt. -)
As discussed in the maintainer meeting on 2024-01-29.

Mainly this is to avoid a situation where the name is parsed and
treated as a file name, mostly to protect users.
.-* and ..-* are also considered invalid because they might strip
on that separator to remove versions. Doesn't really work, but that's
what we decided, and I won't argue with it, because .-* probably
doesn't seem to have a real world application anyway.
We do still permit a 1-character name that's just "-", which still
poses a similar risk in such a situation. We can't start disallowing
trailing -, because a non-zero number of users will need it and we've
seen how annoying and painful such a change is.

What matters most is preventing a situation where . or .. can be
injected, and to just get this done.
2024-01-31 18:35:19 +01:00

13 lines
382 B
C++

#pragma once
///@file
namespace nix {
static constexpr std::string_view nameRegexStr =
// This uses a negative lookahead: (?!\.\.?(-|$))
// - deny ".", "..", or those strings followed by '-'
// - when it's not those, start again at the start of the input and apply the next regex, which is [0-9a-zA-Z\+\-\._\?=]+
R"((?!\.\.?(-|$))[0-9a-zA-Z\+\-\._\?=]+)";
}