Re: [PATCH v2 2/2] man2: Document constant for only allowing absolute paths

From: Steven Stewart-Gallus
Date: Wed Jul 09 2014 - 19:53:46 EST

Signed-off-by: Steven Stewart-Gallus <sstewartgallus00@xxxxxxxxxxxxxxx>

---
man2/access.2 | 14 +++++++++++++-
man2/chmod.2 | 14 +++++++++++++-
man2/chown.2 | 14 +++++++++++++-
man2/fanotify_mark.2 | 15 ++++++++++++++-
man2/futimesat.2 | 14 +++++++++++++-
man2/link.2 | 11 ++++++++++-
man2/mkdir.2 | 14 +++++++++++++-
man2/mknod.2 | 14 +++++++++++++-
man2/open.2 | 14 +++++++++++++-
man2/open_by_handle_at.2 | 8 ++++++++
man2/readlink.2 | 14 +++++++++++++-
man2/rename.2 | 11 ++++++++++-
man2/stat.2 | 14 +++++++++++++-
man2/symlink.2 | 14 +++++++++++++-
man2/unlink.2 | 14 +++++++++++++-
man2/utimensat.2 | 8 ++++++++
man3/readdir.3 | 18 ++++++++++++++----
17 files changed, 207 insertions(+), 18 deletions(-)

diff --git a/man2/access.2 b/man2/access.2
index cdf2f96..f2a030b 100644
--- a/man2/access.2
+++ b/man2/access.2
@@ -141,6 +141,14 @@ directory of the calling process (like
.BR access ()).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -244,7 +252,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B EINVAL
Invalid flag specified in
diff --git a/man2/chmod.2 b/man2/chmod.2
index b46c0fa..1cde0f1 100644
--- a/man2/chmod.2
+++ b/man2/chmod.2
@@ -209,6 +209,14 @@ directory of the calling process (like
.BR chmod ()).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -306,7 +314,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B EINVAL
Invalid flag specified in
diff --git a/man2/chown.2 b/man2/chown.2
index 8f6194e..aafadc5 100644
--- a/man2/chown.2
+++ b/man2/chown.2
@@ -172,6 +172,14 @@ directory of the calling process (like
.BR chown ()).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -295,7 +303,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B EINVAL
Invalid flag specified in
diff --git a/man2/fanotify_mark.2 b/man2/fanotify_mark.2
index d3c7e7d..13bf51d 100644
--- a/man2/fanotify_mark.2
+++ b/man2/fanotify_mark.2
@@ -214,6 +214,14 @@ is absolute, it defines the filesystem object to be marked, and
is ignored.
.IP *
If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+.IP *
+If
.I pathname
is relative, and
.I dirfd
@@ -244,7 +252,12 @@ is set to indicate the error.
.TP
.B EBADF
An invalid file descriptor was passed in
-.IR fanotify_fd .
+.IR fanotify_fd
+or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B EINVAL
An invalid value was passed in
diff --git a/man2/futimesat.2 b/man2/futimesat.2
index e6e0174..2b9298d 100644
--- a/man2/futimesat.2
+++ b/man2/futimesat.2
@@ -77,6 +77,14 @@ directory of the calling process (like
.BR utimes (2)).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -98,7 +106,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B ENOTDIR
.I pathname
diff --git a/man2/link.2 b/man2/link.2
index 0725cd2..d340235 100644
--- a/man2/link.2
+++ b/man2/link.2
@@ -107,6 +107,14 @@ directory of the calling process (like
.BR link ()).

If
+.I olddirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I oldpath
+must be absolute.
+
+If
.I oldpath
is absolute, then
.I olddirfd
@@ -278,7 +286,8 @@ The following additional errors can occur for
.I olddirfd
or
.I newdirfd
-is not a valid file descriptor.
+is not a valid file descriptor or one of them is AT_FDABSOLUTE and the
+associated path is relative.
.TP
.B EINVAL
An invalid flag value was specified in
diff --git a/man2/mkdir.2 b/man2/mkdir.2
index 71f794f..4c18fcb 100644
--- a/man2/mkdir.2
+++ b/man2/mkdir.2
@@ -103,6 +103,14 @@ directory of the calling process (like
.BR mkdir ()).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -190,7 +198,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B ENOTDIR
.I pathname
diff --git a/man2/mknod.2 b/man2/mknod.2
index e93c345..4b8b620 100644
--- a/man2/mknod.2
+++ b/man2/mknod.2
@@ -137,6 +137,14 @@ directory of the calling process (like
.BR mknod (2)).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -230,7 +238,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B ENOTDIR
.I pathname
diff --git a/man2/open.2 b/man2/open.2
index df10a22..c65d705 100644
--- a/man2/open.2
+++ b/man2/open.2
@@ -767,6 +767,14 @@ directory of the calling process (like
.BR open ()).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -998,7 +1006,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B ENOTDIR
.I pathname
diff --git a/man2/open_by_handle_at.2 b/man2/open_by_handle_at.2
index 7badac7..70fafb3 100644
--- a/man2/open_by_handle_at.2
+++ b/man2/open_by_handle_at.2
@@ -181,6 +181,14 @@ or
.BR AT_FDCWD ,
meaning the current working directory,
and a handle is returned for the file to which it refers.
+.IP *
+If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
.PP
The
.I mount_id
diff --git a/man2/readlink.2 b/man2/readlink.2
index 19102e1..e5a0e13 100644
--- a/man2/readlink.2
+++ b/man2/readlink.2
@@ -127,6 +127,14 @@ directory of the calling process (like
.BR readlink ()).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -202,7 +210,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B ENOTDIR
.I pathname
diff --git a/man2/rename.2 b/man2/rename.2
index a258972..c857886 100644
--- a/man2/rename.2
+++ b/man2/rename.2
@@ -151,6 +151,14 @@ directory of the calling process (like
.BR rename ()).

If
+.I olddirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I oldpath
+must be absolute.
+
+If
.I oldpath
is absolute, then
.I olddirfd
@@ -351,7 +359,8 @@ and
.I olddirfd
or
.I newdirfd
-is not a valid file descriptor.
+is not a valid file descriptor or one of them is AT_FDABSOLUTE and the
+associated path is relative.
.TP
.B ENOTDIR
.I oldpath
diff --git a/man2/stat.2 b/man2/stat.2
index b70797d..c210b0d 100644
--- a/man2/stat.2
+++ b/man2/stat.2
@@ -452,6 +452,14 @@ directory of the calling process (like
.BR stat ()).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
@@ -581,7 +589,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B EINVAL
Invalid flag specified in
diff --git a/man2/symlink.2 b/man2/symlink.2
index 8bd067f..b53ca2d 100644
--- a/man2/symlink.2
+++ b/man2/symlink.2
@@ -133,6 +133,14 @@ directory of the calling process (like
.BR symlink ()).

If
+.I newdirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I linkpath
+must be absolute.
+
+If
.I linkpath
is absolute, then
.I newdirfd
@@ -208,7 +216,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I newdirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I newdirfd
+is AT_FDABSOLUTE and
+.I linkpath
+is relative.
.TP
.B ENOENT
.I linkpath
diff --git a/man2/unlink.2 b/man2/unlink.2
index ccc05bf..b6c1591 100644
--- a/man2/unlink.2
+++ b/man2/unlink.2
@@ -119,6 +119,14 @@ directory of the calling process (like
and
.BR rmdir (2)).

+If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
If the pathname given in
.I pathname
is absolute, then
@@ -248,7 +256,11 @@ The following additional errors can occur for
.TP
.B EBADF
.I dirfd
-is not a valid file descriptor.
+is not a valid file descriptor or
+.I dirfd
+is AT_FDABSOLUTE and
+.I pathname
+is relative.
.TP
.B EINVAL
An invalid flag value was specified in
diff --git a/man2/utimensat.2 b/man2/utimensat.2
index 99b985c..c22e1f3 100644
--- a/man2/utimensat.2
+++ b/man2/utimensat.2
@@ -206,6 +206,14 @@ directory of the calling process (like
.BR utimes (2)).

If
+.I dirfd
+is the special value
+.BR AT_FDABSOLUTE ,
+then
+.I pathname
+must be absolute.
+
+If
.I pathname
is absolute, then
.I dirfd
diff --git a/man3/readdir.3 b/man3/readdir.3
index 898ab31..7eda4a7 100644
--- a/man3/readdir.3
+++ b/man3/readdir.3
@@ -250,10 +250,10 @@ as follows:
.in +4n
.nf

-name_max = pathconf(dirpath, _PC_NAME_MAX);
+name_max = fpathconf(fddir, _PC_NAME_MAX);
if (name_max == \-1) /* Limit not defined, or error */
- name_max = 255; /* Take a guess */
-len = offsetof(struct dirent, d_name) + name_max + 1;
+ return ENOSYS; /* Do not take a guess, that is incorrect */
+len = offsetof(struct dirent, d_name) + name_max + 1u;
entryp = malloc(len);

.fi
@@ -261,7 +261,17 @@ entryp = malloc(len);
(POSIX.1 requires that
.I d_name
is the last field in a
-.IR "struct dirent" .)
+.IR "struct dirent" ".)"
+Note that
+.I fpathconf
+is used instead of
+.I pathconf
+to avoid a time of check to time of use security hole. As well,
+.I dirfd
+is not portable to all systems so
+.I readdir_r
+therefore can not be used in a fully portable way. This problem is
+currently under review by the Austin Common Standards Revision Group.
.SH SEE ALSO
.BR getdents (2),
.BR read (2),
--
1.7.9.5


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