From b4a05edbfe49f87555fd284dfb0d6c56ed43217d Mon Sep 17 00:00:00 2001 From: Graham Christensen Date: Sat, 11 May 2019 16:35:53 -0400 Subject: [PATCH] runProgram: support gid, uid, chdir --- src/libstore/build.cc | 32 ++++++++++++++------------------ src/libutil/util.cc | 15 +++++++++++++-- src/libutil/util.hh | 5 +++-- 3 files changed, 30 insertions(+), 22 deletions(-) diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 8397cd0d1..8902e22bd 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -465,26 +465,22 @@ void handleDiffHook(bool allowVfork, uid_t uid, uid_t gid, Path tryA, Path tryB, { auto diffHook = settings.diffHook; if (diffHook != "" && settings.runDiffHook) { - auto wrapper = [&]() { - if (chdir("/") == -1) - throw SysError("chdir / failed"); - if (setgid(gid) == -1) - throw SysError("setgid failed"); - if (setgroups(0, 0) == -1) - throw SysError("setgroups failed"); - if (setuid(uid) == -1) - throw SysError("setuid failed"); + try { + RunOptions diffHookOptions(diffHook,{tryA, tryB, drvPath, tmpDir}); + diffHookOptions.searchPath = true; + diffHookOptions.uid = uid; + diffHookOptions.gid = gid; + diffHookOptions.chdir = "/"; - try { - auto diff = runProgram(diffHook, true, {tryA, tryB, drvPath, tmpDir}); - if (diff != "") - printError(chomp(diff)); - } catch (Error & error) { - printError("diff hook execution failed: %s", error.what()); - } - }; + auto diffRes = runProgram(diffHookOptions); + if (!statusOk(diffRes.first)) + throw ExecError(diffRes.first, fmt("diff-hook program '%1%' %2%", diffHook, statusToString(diffRes.first))); - doFork(allowVfork, wrapper); + if (diffRes.second != "") + printError(chomp(diffRes.second)); + } catch (Error & error) { + printError("diff hook execution failed: %s", error.what()); + } } } diff --git a/src/libutil/util.cc b/src/libutil/util.cc index 0f4d3d92b..55b9144f3 100644 --- a/src/libutil/util.cc +++ b/src/libutil/util.cc @@ -16,6 +16,7 @@ #include #include +#include #include #include #include @@ -914,8 +915,8 @@ void killUser(uid_t uid) /* Wrapper around vfork to prevent the child process from clobbering the caller's stack frame in the parent. */ -pid_t doFork(bool allowVfork, std::function fun) __attribute__((noinline)); -pid_t doFork(bool allowVfork, std::function fun) +static pid_t doFork(bool allowVfork, std::function fun) __attribute__((noinline)); +static pid_t doFork(bool allowVfork, std::function fun) { #ifdef __linux__ pid_t pid = allowVfork ? vfork() : fork(); @@ -1025,6 +1026,16 @@ void runProgram2(const RunOptions & options) if (source && dup2(in.readSide.get(), STDIN_FILENO) == -1) throw SysError("dupping stdin"); + //if (options.chdir && chdir((*options.chdir).c_str()) == -1) + // throw SysError("chdir failed"); + if (options.gid && setgid(*options.gid) == -1) + throw SysError("setgid failed"); + /* Drop all other groups if we're setgid. */ + if (options.gid && setgroups(0, 0) == -1) + throw SysError("setgroups failed"); + if (options.uid && setuid(*options.uid) == -1) + throw SysError("setuid failed"); + Strings args_(options.args); args_.push_front(options.program); diff --git a/src/libutil/util.hh b/src/libutil/util.hh index 824a35b98..7c57d0afa 100644 --- a/src/libutil/util.hh +++ b/src/libutil/util.hh @@ -265,10 +265,11 @@ string runProgram(Path program, bool searchPath = false, const Strings & args = Strings(), const std::optional & input = {}); -pid_t doFork(bool allowVfork, std::function fun); - struct RunOptions { + std::optional uid; + std::optional gid; + std::optional chdir; Path program; bool searchPath = true; Strings args;