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

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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.
This commit is contained in:
Bruce Momjian 2011-02-12 09:47:51 -05:00
parent b313bca0af
commit 0de0cc150a
4 changed files with 73 additions and 48 deletions
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40
contrib/adminpack/adminpack.c
View File

@ -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;
}

39
src/backend/utils/adt/genfile.c
View File

@ -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;
}

9
src/include/port.h
View File

@ -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]) || \

33
src/port/path.c
View File

@ -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).
*