coreutils: CVE-2017-18018

CVE-2017-18018-1:
doc: clarify chown/chgrp --dereference defaults
* doc/coreutils.texi: the documentation for the --dereference
  flag of chown/chgrp states that it is the default mode of
  operation. Document that this is only the case when operating
  non-recursively.

CVE-2017-18018-2:
doc: warn about following symlinks recursively in chown/chgrp
In both chown and chgrp (which shares its code with chown), operating
on symlinks recursively has a window of vulnerability where the
destination user or group can change the target of the operation.
Warn about combining the --dereference, --recursive, and -L flags.

* doc/coreutils.texi (warnOptDerefWithRec): Add macro.
(node chown invocation): Add it to --dereference and -L.
(node chgrp invocation): Likewise.

Affects coreutils <= 8.29

Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

3 files changed, 125 insertions, 0 deletions

diff --git a/meta/recipes-core/coreutils/coreutils/CVE-2017-18018-1.patch b/meta/recipes-core/coreutils/coreutils/CVE-2017-18018-1.patch
new file mode 100644
index 0000000000..6f31eba26d
--- /dev/null
+++ b/meta/recipes-core/coreutils/coreutils/CVE-2017-18018-1.patch
@@ -0,0 +1,40 @@
+From 7597cfa482e42a00a69fb9577ee523762980a9a2 Mon Sep 17 00:00:00 2001
+From: Michael Orlitzky <michael@orlitzky.com>
+Date: Thu, 28 Dec 2017 15:52:42 -0500
+Subject: doc: clarify chown/chgrp --dereference defaults
+
+* doc/coreutils.texi: the documentation for the --dereference
+  flag of chown/chgrp states that it is the default mode of
+  operation. Document that this is only the case when operating
+  non-recursively.
+
+CVE: CVE-2017-18018
+Upstream-Status: Backport from v8.30
+
+Signed-off-by: Michael Orlitzky <michael@orlitzky.com>
+Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com>
+---
+ doc/coreutils.texi | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff -Naurp coreutils-8.27_org/doc/coreutils.texi coreutils-8.27/doc/coreutils.texi
+--- coreutils-8.27_org/doc/coreutils.texi	2018-07-22 21:09:50.128736692 -0700
++++ coreutils-8.27/doc/coreutils.texi	2018-07-22 21:12:59.972219770 -0700
+@@ -10952,7 +10952,7 @@ chown -h -R --from=OLDUSER NEWUSER /
+ @cindex symbolic links, changing owner
+ @findex lchown
+ Do not act on symbolic links themselves but rather on what they point to.
+-This is the default.
++This is the default when not operating recursively.
+ 
+ @item -h
+ @itemx --no-dereference
+@@ -11082,7 +11082,7 @@ changed.
+ @cindex symbolic links, changing owner
+ @findex lchown
+ Do not act on symbolic links themselves but rather on what they point to.
+-This is the default.
++This is the default when not operating recursively.
+ 
+ @item -h
+ @itemx --no-dereference
diff --git a/meta/recipes-core/coreutils/coreutils/CVE-2017-18018-2.patch b/meta/recipes-core/coreutils/coreutils/CVE-2017-18018-2.patch
new file mode 100644
index 0000000000..c8f5f54acf
--- /dev/null
+++ b/meta/recipes-core/coreutils/coreutils/CVE-2017-18018-2.patch
@@ -0,0 +1,83 @@
+From bc2fd9796403e03bb757b064d44c22fab92e6842 Mon Sep 17 00:00:00 2001
+From: Michael Orlitzky <michael@orlitzky.com>
+Date: Thu, 4 Jan 2018 11:38:21 -0500
+Subject: doc: warn about following symlinks recursively in chown/chgrp
+
+In both chown and chgrp (which shares its code with chown), operating
+on symlinks recursively has a window of vulnerability where the
+destination user or group can change the target of the operation.
+Warn about combining the --dereference, --recursive, and -L flags.
+
+* doc/coreutils.texi (warnOptDerefWithRec): Add macro.
+(node chown invocation): Add it to --dereference and -L.
+(node chgrp invocation): Likewise.
+
+See also: CVE-2017-18018
+CVE: CVE-2017-18018
+Upstream-Status: Backport from v8.30
+
+Signed-off-by: Michael Orlitzky <michael@orlitzky.com>
+Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com>
+---
+ doc/coreutils.texi | 17 +++++++++++++++++
+ 1 file changed, 17 insertions(+)
+
+diff --git a/doc/coreutils.texi b/doc/coreutils.texi
+index 6bb9f09..9f5f95b 100644
+--- a/doc/coreutils.texi
++++ b/doc/coreutils.texi
+@@ -1428,6 +1428,19 @@ a command line argument is a symbolic link to a directory, traverse it.
+ In a recursive traversal, traverse every symbolic link to a directory
+ that is encountered.
+ @end macro
++
++@c Append the following warning to -L where appropriate (e.g. chown).
++@macro warnOptDerefWithRec
++
++Combining this dereferencing option with the @option{--recursive} option
++may create a security risk:
++During the traversal of the directory tree, an attacker may be able to
++introduce a symlink to an arbitrary target; when the tool reaches that,
++the operation will be performed on the target of that symlink,
++possibly allowing the attacker to escalate privileges.
++
++@end macro
++
+ @choptL
+ 
+ @macro choptP
+@@ -10995,6 +11008,7 @@ chown -h -R --from=OLDUSER NEWUSER /
+ @findex lchown
+ Do not act on symbolic links themselves but rather on what they point to.
+ This is the default when not operating recursively.
++@warnOptDerefWithRec
+ 
+ @item -h
+ @itemx --no-dereference
+@@ -11051,6 +11065,7 @@ Recursively change ownership of directories and their contents.
+ @xref{Traversing symlinks}.
+ 
+ @choptL
++@warnOptDerefWithRec
+ @xref{Traversing symlinks}.
+ 
+ @choptP
+@@ -11125,6 +11140,7 @@ changed.
+ @findex lchown
+ Do not act on symbolic links themselves but rather on what they point to.
+ This is the default when not operating recursively.
++@warnOptDerefWithRec
+ 
+ @item -h
+ @itemx --no-dereference
+@@ -11180,6 +11196,7 @@ Recursively change the group ownership of directories and their contents.
+ @xref{Traversing symlinks}.
+ 
+ @choptL
++@warnOptDerefWithRec
+ @xref{Traversing symlinks}.
+ 
+ @choptP
+-- 
+cgit v1.0-41-gc330
+
diff --git a/meta/recipes-core/coreutils/coreutils_8.29.bb b/meta/recipes-core/coreutils/coreutils_8.29.bb
index 4704f32196..b0572afdc0 100644
--- a/meta/recipes-core/coreutils/coreutils_8.29.bb
+++ b/meta/recipes-core/coreutils/coreutils_8.29.bb
@@ -19,6 +19,8 @@ SRC_URI = "${GNU_MIRROR}/coreutils/${BP}.tar.xz \
            file://0001-uname-report-processor-and-hardware-correctly.patch \
            file://disable-ls-output-quoting.patch \
            file://0001-local.mk-fix-cross-compiling-problem.patch \
+           file://CVE-2017-18018-1.patch \
+           file://CVE-2017-18018-2.patch \
           "
 
 SRC_URI[md5sum] = "960cfe75a42c9907c71439f8eb436303"