From 30ce69b5cb05712c3a4903b0f397912119c4f1f9 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 31 Oct 2021 13:26:57 +0200
Subject: [PATCH] Improve robustness of resolving user/group names in Stat

---
 source/fs/android/stat_owner.cpp  | 26 ++++++++++++++++++--------
 source/fs/stat_private.h          |  4 ++--
 source/fs/unix/stat_owner.cpp     | 30 ++++++++++++++++++++----------
 source/fs/unix/stat_platform.h    |  3 +++
 source/fs/windows/stat.cpp        |  8 ++++----
 source/fs/windows/stat_platform.h |  3 +++
 6 files changed, 50 insertions(+), 24 deletions(-)

diff --git a/source/fs/android/stat_owner.cpp b/source/fs/android/stat_owner.cpp
index 45fba30..48823e9 100644
--- a/source/fs/android/stat_owner.cpp
+++ b/source/fs/android/stat_owner.cpp
@@ -9,17 +9,27 @@ namespace FS {
 
 void Stat::Private::fill_owner_info(Stat::OwnerInfo &result)
 {
-	struct passwd *owner;
-	if((owner = getpwuid(owner_id)))
-		result.owner = owner->pw_name;
+	if(owner_id!=INVALID_UID)
+	{
+		struct passwd *owner;
+		if((owner = getpwuid(owner_id)))
+			result.owner = owner->pw_name;
+		else
+			result.owner = format("%d", owner_id);
+	}
 	else
-		result.owner = format("%d", owner_id);
+		result.owner = "None";
 
-	struct group *group;
-	if((group = getgrgid(group_id)))
-		result.group = group->gr_name;
+	if(group_id!=INVALID_GID)
+	{
+		struct group *group;
+		if((group = getgrgid(group_id)))
+			result.group = group->gr_name;
+		else
+			result.group = format("%d", group_id);
+	}
 	else
-		result.group = format("%d", group_id);
+		result.group = "None";
 }
 
 } // namespace FS
diff --git a/source/fs/stat_private.h b/source/fs/stat_private.h
index 7b20638..60438a2 100644
--- a/source/fs/stat_private.h
+++ b/source/fs/stat_private.h
@@ -8,8 +8,8 @@ namespace FS {
 
 struct Stat::Private
 {
-	UserID owner_id;
-	GroupID group_id;
+	UserID owner_id = INVALID_UID;
+	GroupID group_id = INVALID_GID;
 
 	Private();
 	Private(const Private &);
diff --git a/source/fs/unix/stat_owner.cpp b/source/fs/unix/stat_owner.cpp
index 1a33d74..9c643d9 100644
--- a/source/fs/unix/stat_owner.cpp
+++ b/source/fs/unix/stat_owner.cpp
@@ -11,19 +11,29 @@ void Stat::Private::fill_owner_info(Stat::OwnerInfo &result)
 {
 	char buf[1024];
 
-	struct passwd pw;
-	struct passwd *owner;
-	if(!getpwuid_r(owner_id, &pw, buf, sizeof(buf), &owner) && owner)
-		result.owner = owner->pw_name;
+	if(owner_id!=INVALID_UID)
+	{
+		struct passwd pw;
+		struct passwd *owner;
+		if(!getpwuid_r(owner_id, &pw, buf, sizeof(buf), &owner) && owner)
+			result.owner = owner->pw_name;
+		else
+			result.owner = format("%d", owner_id);
+	}
 	else
-		result.owner = format("%d", owner_id);
+		result.owner = "None";
 
-	struct group gr;
-	struct group *group;
-	if(!getgrgid_r(group_id, &gr, buf, sizeof(buf), &group) && group)
-		result.group = group->gr_name;
+	if(group_id!=INVALID_GID)
+	{
+		struct group gr;
+		struct group *group;
+		if(!getgrgid_r(group_id, &gr, buf, sizeof(buf), &group) && group)
+			result.group = group->gr_name;
+		else
+			result.group = format("%d", group_id);
+	}
 	else
-		result.group = format("%d", group_id);
+		result.group = "None";
 }
 
 } // namespace FS
diff --git a/source/fs/unix/stat_platform.h b/source/fs/unix/stat_platform.h
index cc3f095..d888fed 100644
--- a/source/fs/unix/stat_platform.h
+++ b/source/fs/unix/stat_platform.h
@@ -9,6 +9,9 @@ namespace FS {
 typedef uid_t UserID;
 typedef gid_t GroupID;
 
+const UserID INVALID_UID = -1;
+const GroupID INVALID_GID = -1;
+
 } // namespace FS
 } // namespace Msp
 
diff --git a/source/fs/windows/stat.cpp b/source/fs/windows/stat.cpp
index ac9e0c9..36f28a0 100644
--- a/source/fs/windows/stat.cpp
+++ b/source/fs/windows/stat.cpp
@@ -50,20 +50,20 @@ Stat::Private::Private(const Private &other):
 
 Stat::Private::~Private()
 {
-	if(owner_id)
+	if(owner_id!=INVALID_UID)
 		HeapFree(GetProcessHeap(), 0, owner_id);
-	if(group_id)
+	if(group_id!=INVALID_GID)
 		HeapFree(GetProcessHeap(), 0, group_id);
 }
 
 void Stat::Private::fill_owner_info(Stat::OwnerInfo &result)
 {
-	if(owner_id)
+	if(owner_id!=INVALID_UID)
 		result.owner = get_account_name(owner_id);
 	else
 		result.owner = "None";
 
-	if(group_id)
+	if(group_id!=INVALID_GID)
 		result.group = get_account_name(group_id);
 	else
 		result.group = "None";
diff --git a/source/fs/windows/stat_platform.h b/source/fs/windows/stat_platform.h
index 4e8cfbc..c193acc 100644
--- a/source/fs/windows/stat_platform.h
+++ b/source/fs/windows/stat_platform.h
@@ -9,6 +9,9 @@ namespace FS {
 typedef PSID UserID;
 typedef PSID GroupID;
 
+const UserID INVALID_UID = 0;
+const GroupID INVALID_GID = 0;
+
 } // namespace FS
 } // namespace Msp
 
-- 
2.45.2