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Merge pull request #14723 from NixOS/peer-info

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daemon.cc: Clean up PeerInfo by using std::optional
This commit is contained in:
Eelco Dolstra 2025-12-08 17:57:31 +00:00 • committed by GitHub
commit a95580e468
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1 changed files with 35 additions and 32 deletions
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67
src/nix/unix/daemon.cc
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@ -174,22 +174,23 @@ static bool matchUser(std::string_view user, const struct group & gr)
*
* Otherwise: No.
*/
static bool matchUser(const std::string & user, const std::string & group, const Strings & users)
static bool
matchUser(const std::optional<std::string> & user, const std::optional<std::string> & group, const Strings & users)
{
if (find(users.begin(), users.end(), "*") != users.end())
return true;
if (find(users.begin(), users.end(), user) != users.end())
if (user && find(users.begin(), users.end(), *user) != users.end())
return true;
for (auto & i : users)
if (i.substr(0, 1) == "@") {
if (group == i.substr(1))
if (group && *group == i.substr(1))
return true;
struct group * gr = getgrnam(i.c_str() + 1);
if (!gr)
continue;
if (matchUser(user, *gr))
if (user && matchUser(*user, *gr))
return true;
}
@ -198,12 +199,9 @@ static bool matchUser(const std::string & user, const std::string & group, const
struct PeerInfo
{
bool pidKnown;
pid_t pid;
bool uidKnown;
uid_t uid;
bool gidKnown;
gid_t gid;
std::optional<pid_t> pid;
std::optional<uid_t> uid;
std::optional<gid_t> gid;
};
/**
@ -211,7 +209,7 @@ struct PeerInfo
*/
static PeerInfo getPeerInfo(int remote)
{
PeerInfo peer = {false, 0, false, 0, false, 0};
PeerInfo peer;
#if defined(SO_PEERCRED)
@ -221,9 +219,11 @@ static PeerInfo getPeerInfo(int remote)
ucred cred;
# endif
socklen_t credLen = sizeof(cred);
if (getsockopt(remote, SOL_SOCKET, SO_PEERCRED, &cred, &credLen) == -1)
throw SysError("getting peer credentials");
peer = {true, cred.pid, true, cred.uid, true, cred.gid};
if (getsockopt(remote, SOL_SOCKET, SO_PEERCRED, &cred, &credLen) == 0) {
peer.pid = cred.pid;
peer.uid = cred.uid;
peer.gid = cred.gid;
}
#elif defined(LOCAL_PEERCRED)
@ -233,9 +233,8 @@ static PeerInfo getPeerInfo(int remote)
xucred cred;
socklen_t credLen = sizeof(cred);
if (getsockopt(remote, SOL_LOCAL, LOCAL_PEERCRED, &cred, &credLen) == -1)
throw SysError("getting peer credentials");
peer = {false, 0, true, cred.cr_uid, false, 0};
if (getsockopt(remote, SOL_LOCAL, LOCAL_PEERCRED, &cred, &credLen) == 0)
peer.uid = cred.cr_uid;
#endif
@ -266,15 +265,19 @@ static ref<Store> openUncachedStore()
*
* If the potential client is not allowed to talk to us, we throw an `Error`.
*/
static std::pair<TrustedFlag, std::string> authPeer(const PeerInfo & peer)
static std::pair<TrustedFlag, std::optional<std::string>> authPeer(const PeerInfo & peer)
{
TrustedFlag trusted = NotTrusted;
struct passwd * pw = peer.uidKnown ? getpwuid(peer.uid) : 0;
std::string user = pw ? pw->pw_name : std::to_string(peer.uid);
auto pw = peer.uid ? getpwuid(*peer.uid) : nullptr;
auto user = pw ? std::optional<std::string>(pw->pw_name)
: peer.uid ? std::optional(std::to_string(*peer.uid))
: std::nullopt;
struct group * gr = peer.gidKnown ? getgrgid(peer.gid) : 0;
std::string group = gr ? gr->gr_name : std::to_string(peer.gid);
auto gr = peer.gid ? getgrgid(*peer.gid) : 0;
auto group = gr ? std::optional<std::string>(gr->gr_name)
: peer.gid ? std::optional(std::to_string(*peer.gid))
: std::nullopt;
const Strings & trustedUsers = authorizationSettings.trustedUsers;
const Strings & allowedUsers = authorizationSettings.allowedUsers;
@ -283,7 +286,7 @@ static std::pair<TrustedFlag, std::string> authPeer(const PeerInfo & peer)
trusted = Trusted;
if ((!trusted && !matchUser(user, group, allowedUsers)) || group == settings.buildUsersGroup)
throw Error("user '%1%' is not allowed to connect to the Nix daemon", user);
throw Error("user '%1%' is not allowed to connect to the Nix daemon", user.value_or("<unknown>"));
return {trusted, std::move(user)};
}
@ -360,23 +363,23 @@ static void daemonLoop(std::optional<TrustedFlag> forceTrustClientOpt)
unix::closeOnExec(remote.get());
PeerInfo peer{.pidKnown = false};
PeerInfo peer;
TrustedFlag trusted;
std::string user;
std::optional<std::string> userName;
if (forceTrustClientOpt)
trusted = *forceTrustClientOpt;
else {
peer = getPeerInfo(remote.get());
auto [_trusted, _user] = authPeer(peer);
auto [_trusted, _userName] = authPeer(peer);
trusted = _trusted;
user = _user;
userName = _userName;
};
printInfo(
(std::string) "accepted connection from pid %1%, user %2%" + (trusted ? " (trusted)" : ""),
peer.pidKnown ? std::to_string(peer.pid) : "<unknown>",
peer.uidKnown ? user : "<unknown>");
peer.pid ? std::to_string(*peer.pid) : "<unknown>",
userName.value_or("<unknown>"));
// Fork a child to handle the connection.
ProcessOptions options;
@ -396,8 +399,8 @@ static void daemonLoop(std::optional<TrustedFlag> forceTrustClientOpt)
setSigChldAction(false);
// For debugging, stuff the pid into argv[1].
if (peer.pidKnown && savedArgv[1]) {
auto processName = std::to_string(peer.pid);
if (peer.pid && savedArgv[1]) {
auto processName = std::to_string(*peer.pid);
strncpy(savedArgv[1], processName.c_str(), strlen(savedArgv[1]));
}
@ -414,7 +417,7 @@ static void daemonLoop(std::optional<TrustedFlag> forceTrustClientOpt)
} catch (Error & error) {
auto ei = error.info();
// FIXME: add to trace?
ei.msg = HintFmt("error processing connection: %1%", ei.msg.str());
ei.msg = HintFmt("while processing connection: %1%", ei.msg.str());
logError(ei);
}
}