Linux v4.17.5

1 files changed, 47 insertions, 0 deletions

diff --git a/CVE-2018-13405.patch b/CVE-2018-13405.patch
new file mode 100644
index 000000000..489e11f54
--- /dev/null
+++ b/CVE-2018-13405.patch
@@ -0,0 +1,47 @@
+From 0fa3ecd87848c9c93c2c828ef4c3a8ca36ce46c7 Mon Sep 17 00:00:00 2001
+From: Linus Torvalds <torvalds@linux-foundation.org>
+Date: Tue, 3 Jul 2018 17:10:19 -0700
+Subject: [PATCH] Fix up non-directory creation in SGID directories
+
+sgid directories have special semantics, making newly created files in
+the directory belong to the group of the directory, and newly created
+subdirectories will also become sgid.  This is historically used for
+group-shared directories.
+
+But group directories writable by non-group members should not imply
+that such non-group members can magically join the group, so make sure
+to clear the sgid bit on non-directories for non-members (but remember
+that sgid without group execute means "mandatory locking", just to
+confuse things even more).
+
+Reported-by: Jann Horn <jannh@google.com>
+Cc: Andy Lutomirski <luto@kernel.org>
+Cc: Al Viro <viro@zeniv.linux.org.uk>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Jeremy Cline <jcline@redhat.com>
+---
+ fs/inode.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/fs/inode.c b/fs/inode.c
+index 2c300e981796..8c86c809ca17 100644
+--- a/fs/inode.c
++++ b/fs/inode.c
+@@ -1999,8 +1999,14 @@ void inode_init_owner(struct inode *inode, const struct inode *dir,
+ 	inode->i_uid = current_fsuid();
+ 	if (dir && dir->i_mode & S_ISGID) {
+ 		inode->i_gid = dir->i_gid;
++
++		/* Directories are special, and always inherit S_ISGID */
+ 		if (S_ISDIR(mode))
+ 			mode |= S_ISGID;
++		else if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP) &&
++			 !in_group_p(inode->i_gid) &&
++			 !capable_wrt_inode_uidgid(dir, CAP_FSETID))
++			mode &= ~S_ISGID;
+ 	} else
+ 		inode->i_gid = current_fsgid();
+ 	inode->i_mode = mode;
+-- 
+2.17.1
+