From 492d895632c23bbfe01f90eea61e708b60abb587 Mon Sep 17 00:00:00 2001
From: Antonio SJ Musumeci <trapexit@spawn.link>
Date: Wed, 15 Feb 2017 09:08:27 -0500
Subject: [PATCH] check metadata on chown/chmod errors when cloning

---
 src/fs_base_chmod.hpp | 56 +++++++++++++++++++++++++++++++++++++
 src/fs_base_chown.hpp | 65 +++++++++++++++++++++++++++++++++++++++++++
 src/fs_clonefile.cpp  |  4 +--
 src/fs_clonepath.cpp  |  4 +--
 4 files changed, 125 insertions(+), 4 deletions(-)

diff --git a/src/fs_base_chmod.hpp b/src/fs_base_chmod.hpp
index 39692d2f..2334def1 100644
--- a/src/fs_base_chmod.hpp
+++ b/src/fs_base_chmod.hpp
@@ -21,6 +21,10 @@
 
 #include <sys/stat.h>
 
+#include "fs_base_stat.hpp"
+
+#define MODE_BITS (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO)
+
 namespace fs
 {
   static
@@ -49,6 +53,58 @@ namespace fs
   {
     return ::fchmod(fd,st.st_mode);
   }
+
+  static
+  inline
+  int
+  chmod_check_on_error(const std::string &path,
+                       const mode_t       mode)
+  {
+    int rv;
+
+    rv = fs::chmod(path,mode);
+    if(rv == -1)
+      {
+        int error;
+        struct stat st;
+
+        error = errno;
+        rv = fs::stat(path,st);
+        if(rv == -1)
+          return -1;
+
+        if((st.st_mode & MODE_BITS) != (mode & MODE_BITS))
+          return (errno=error,-1);
+      }
+
+    return 0;
+  }
+
+  static
+  inline
+  int
+  fchmod_check_on_error(const int          fd,
+                        const struct stat &st)
+  {
+    int rv;
+
+    rv = fs::fchmod(fd,st);
+    if(rv == -1)
+      {
+        int error;
+        struct stat tmpst;
+
+        error = errno;
+        rv = fs::fstat(fd,tmpst);
+        if(rv == -1)
+          return -1;
+
+        if((st.st_mode & MODE_BITS) != (tmpst.st_mode & MODE_BITS))
+          return (errno=error,-1);
+      }
+
+    return 0;
+  }
 }
 
 #endif
diff --git a/src/fs_base_chown.hpp b/src/fs_base_chown.hpp
index 47b01741..a17fb60b 100644
--- a/src/fs_base_chown.hpp
+++ b/src/fs_base_chown.hpp
@@ -25,6 +25,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include "fs_base_stat.hpp"
+
 namespace fs
 {
   static
@@ -56,6 +58,15 @@ namespace fs
     return ::lchown(path.c_str(),uid,gid);
   }
 
+  static
+  inline
+  int
+  lchown(const std::string &path,
+         const struct stat &st)
+  {
+    return fs::lchown(path,st.st_uid,st.st_gid);
+  }
+
   static
   inline
   int
@@ -74,6 +85,60 @@ namespace fs
   {
     return fs::fchown(fd,st.st_uid,st.st_gid);
   }
+
+  static
+  inline
+  int
+  lchown_check_on_error(const std::string &path,
+                        const struct stat &st)
+  {
+    int rv;
+
+    rv = fs::lchown(path,st);
+    if(rv == -1)
+      {
+        int error;
+        struct stat tmpst;
+
+        error = errno;
+        rv = fs::lstat(path,tmpst);
+        if(rv == -1)
+          return -1;
+
+        if((st.st_uid != tmpst.st_uid) ||
+           (st.st_gid != tmpst.st_gid))
+          return (errno=error,-1);
+      }
+
+    return 0;
+  }
+
+  static
+  inline
+  int
+  fchown_check_on_error(const int          fd,
+                        const struct stat &st)
+  {
+    int rv;
+
+    rv = fs::fchown(fd,st);
+    if(rv == -1)
+      {
+        int error;
+        struct stat tmpst;
+
+        error = errno;
+        rv = fs::fstat(fd,tmpst);
+        if(rv == -1)
+          return -1;
+
+        if((st.st_uid != tmpst.st_uid) ||
+           (st.st_gid != tmpst.st_gid))
+          return (errno=error,-1);
+      }
+
+    return 0;
+  }
 }
 
 #endif
diff --git a/src/fs_clonefile.cpp b/src/fs_clonefile.cpp
index a933536e..826790b9 100644
--- a/src/fs_clonefile.cpp
+++ b/src/fs_clonefile.cpp
@@ -176,11 +176,11 @@ namespace fs
     if((rv == -1) && !ignorable_error(errno))
       return -1;
 
-    rv = fs::fchown(fdout,stin);
+    rv = fs::fchown_check_on_error(fdout,stin);
     if(rv == -1)
       return -1;
 
-    rv = fs::fchmod(fdout,stin);
+    rv = fs::fchmod_check_on_error(fdout,stin);
     if(rv == -1)
       return -1;
 
diff --git a/src/fs_clonepath.cpp b/src/fs_clonepath.cpp
index c81e6432..f4fb32ce 100644
--- a/src/fs_clonepath.cpp
+++ b/src/fs_clonepath.cpp
@@ -82,7 +82,7 @@ namespace fs
         if(errno != EEXIST)
           return -1;
 
-        rv = fs::chmod(topath,st.st_mode);
+        rv = fs::chmod_check_on_error(topath,st.st_mode);
         if(rv == -1)
           return -1;
       }
@@ -96,7 +96,7 @@ namespace fs
     if((rv == -1) && !ignorable_error(errno))
       return -1;
 
-    rv = fs::chown(topath,st);
+    rv = fs::lchown_check_on_error(topath,st);
     if(rv == -1)
       return -1;