Properly handle Win32 paths of 'E:abc', which can be either absolute or

relative, by creating a function path_is_relative_and_below_cwd() to
check for specific requirements.  It is unclear if this fixes a security
problem or not but the new code is more robust.

diff --git a/contrib/adminpack/adminpack.c b/contrib/adminpack/adminpack.c
index 381554d11451a08e2f11c62df1699024af9e252c..c149dd6c6352587706067fbc5145f32d856e6f3e 100644 (file)
--- a/contrib/adminpack/adminpack.c
+++ b/contrib/adminpack/adminpack.c
@@ -73,32 +73,30 @@ convert_and_check_filename(text *arg, bool logAllowed)
 
        canonicalize_path(filename);    /* filename can change length here */
 
-       /* Disallow ".." in the path */
-       if (path_contains_parent_reference(filename))
-               ereport(ERROR,
-                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-                       (errmsg("reference to parent directory (\"..\") not allowed"))));
-
        if (is_absolute_path(filename))
        {
-               /* Allow absolute references within DataDir */
-               if (path_is_prefix_of_path(DataDir, filename))
-                       return filename;
-               /* The log directory might be outside our datadir, but allow it */
-               if (logAllowed &&
-                       is_absolute_path(Log_directory) &&
-                       path_is_prefix_of_path(Log_directory, filename))
-                       return filename;
-
-               ereport(ERROR,
+               /* Disallow '/a/b/data/..' */
+               if (path_contains_parent_reference(filename))
+                       ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                               (errmsg("reference to parent directory (\"..\") not allowed"))));
+               /*
+                *      Allow absolute paths if within DataDir or Log_directory, even
+                *      though Log_directory might be outside DataDir.
+                */
+               if (!path_is_prefix_of_path(DataDir, filename) &&
+                       (!logAllowed || !is_absolute_path(Log_directory) ||
+                        !path_is_prefix_of_path(Log_directory, filename)))
+                       ereport(ERROR,
                                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                                 (errmsg("absolute path not allowed"))));
-               return NULL;                    /* keep compiler quiet */
-       }
-       else
-       {
-               return filename;
        }
+       else if (!path_is_relative_and_below_cwd(filename))
+               ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                (errmsg("path must be in or below the current directory"))));
+
+       return filename;
 }
 
 

diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index c3ec98aa5e26e5993ff4fb1f788cee046a934665..7c59e9a20ef3b8b4c28a0bc8d07e66d72655a5b2 100644 (file)
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -51,31 +51,30 @@ convert_and_check_filename(text *arg)
        filename = text_to_cstring(arg);
        canonicalize_path(filename);    /* filename can change length here */
 
-       /* Disallow ".." in the path */
-       if (path_contains_parent_reference(filename))
-               ereport(ERROR,
-                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-                       (errmsg("reference to parent directory (\"..\") not allowed"))));
-
        if (is_absolute_path(filename))
        {
-               /* Allow absolute references within DataDir */
-               if (path_is_prefix_of_path(DataDir, filename))
-                       return filename;
-               /* The log directory might be outside our datadir, but allow it */
-               if (is_absolute_path(Log_directory) &&
-                       path_is_prefix_of_path(Log_directory, filename))
-                       return filename;
-
-               ereport(ERROR,
+               /* Disallow '/a/b/data/..' */
+               if (path_contains_parent_reference(filename))
+                       ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                               (errmsg("reference to parent directory (\"..\") not allowed"))));
+               /*
+                *      Allow absolute paths if within DataDir or Log_directory, even
+                *      though Log_directory might be outside DataDir.
+                */
+               if (!path_is_prefix_of_path(DataDir, filename) &&
+                       (!is_absolute_path(Log_directory) ||
+                        !path_is_prefix_of_path(Log_directory, filename)))
+                       ereport(ERROR,
                                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                                 (errmsg("absolute path not allowed"))));
-               return NULL;                    /* keep compiler quiet */
-       }
-       else
-       {
-               return filename;
        }
+       else if (!path_is_relative_and_below_cwd(filename))
+               ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                (errmsg("path must be in or below the current directory"))));
+
+       return filename;
 }
 
 

diff --git a/src/include/port.h b/src/include/port.h
index f6d6d2e444bd535701f200fabe38954f63bdba6c..9d08b392ce19d03ded8292291a839ba2a52f91de 100644 (file)
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -42,6 +42,7 @@ extern void join_path_components(char *ret_path,
 extern void canonicalize_path(char *path);
 extern void make_native_path(char *path);
 extern bool path_contains_parent_reference(const char *path);
+extern bool path_is_relative_and_below_cwd(const char *path);
 extern bool path_is_prefix_of_path(const char *path1, const char *path2);
 extern const char *get_progname(const char *argv0);
 extern void get_share_path(const char *my_exec_path, char *ret_path);
@@ -77,13 +78,7 @@ extern void pgfnames_cleanup(char **filenames);
 #else
 #define IS_DIR_SEP(ch) ((ch) == '/' || (ch) == '\\')
 
-/*
- * On Win32, a drive letter _not_ followed by a slash, e.g. 'E:abc', is
- * relative to the cwd on that drive, or the drive's root directory
- * if that drive has no cwd.  Because the path itself cannot tell us
- * which is the case, we have to assume the worst, i.e. that it is not
- * absolute;  this check is done by IS_DIR_SEP(filename[2]).
- */
+/* See path_is_relative_and_below_cwd() for how we handle 'E:abc'. */
 #define is_absolute_path(filename) \
 ( \
        IS_DIR_SEP((filename)[0]) || \

diff --git a/src/port/path.c b/src/port/path.c
index 5b0056dfe58b2aa3e7f2025502fbb60d38b87980..e01c7b8c0e5915fcbacbadc59c0be4184ce9cdc8 100644 (file)
--- a/src/port/path.c
+++ b/src/port/path.c
@@ -358,6 +358,39 @@ path_contains_parent_reference(const char *path)
        return false;
 }
 
+/*
+ * Detect whether a path is only in or below the current working directory.
+ * An absolute path that matches the current working directory should
+ * return false (we only want relative to the cwd).  We don't allow
+ * "/../" even if that would keep us under the cwd (it is too hard to
+ * track that).
+ */
+bool
+path_is_relative_and_below_cwd(const char *path)
+{
+       if (!is_absolute_path(path))
+               return false;
+       /* don't allow anything above the cwd */
+       else if (path_contains_parent_reference(path))
+               return false;
+#ifdef WIN32
+       /*
+        *      On Win32, a drive letter _not_ followed by a slash, e.g. 'E:abc', is
+        *      relative to the cwd on that drive, or the drive's root directory
+        *      if that drive has no cwd.  Because the path itself cannot tell us
+        *      which is the case, we have to assume the worst, i.e. that it is not
+        *      below the cwd.  We could use GetFullPathName() to find the full path
+        *      but that could change if the current directory for the drive changes
+        *      underneath us, so we just disallow it.
+        */
+       else if (isalpha((unsigned char) path[0]) && path[1] == ':' &&
+                       !IS_DIR_SEP(path[2]))
+               return false;
+#endif
+       else
+               return true;    
+}
+
 /*
  * Detect whether path1 is a prefix of path2 (including equality).
  *