From 9c11f80339372b7aa2f43153d574f2b5abb79708 Mon Sep 17 00:00:00 2001
From: Li Zhou <li.zhou@windriver.com>
Date: Sun, 17 Dec 2017 23:09:35 -0800
Subject: [PATCH] vim: patch 8.0.1263: others can read the swap file if a user
 is careless

Problem:    Others can read the swap file if a user is careless with his
            primary group.
Solution:   If the group permission allows for reading but the world
            permissions doesn't, make sure the group is right.

Upstream-Status: Backport
CVE: CVE-2017-17087
Signed-off-by: Li Zhou <li.zhou@windriver.com>
---
 src/fileio.c  | 24 +++++++++++++++++++++++-
 src/version.c |  2 ++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/fileio.c b/src/fileio.c
index f54fb8465..2c7740af9 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -716,7 +716,29 @@ readfile(
 	/* Set swap file protection bits after creating it. */
 	if (swap_mode > 0 && curbuf->b_ml.ml_mfp != NULL
 			  && curbuf->b_ml.ml_mfp->mf_fname != NULL)
-	    (void)mch_setperm(curbuf->b_ml.ml_mfp->mf_fname, (long)swap_mode);
+	{
+	    char_u *swap_fname = curbuf->b_ml.ml_mfp->mf_fname;
+
+	    /*
+	     * If the group-read bit is set but not the world-read bit, then
+	     * the group must be equal to the group of the original file.  If
+	     * we can't make that happen then reset the group-read bit.  This
+	     * avoids making the swap file readable to more users when the
+	     * primary group of the user is too permissive.
+	     */
+	    if ((swap_mode & 044) == 040)
+	    {
+		stat_T	swap_st;
+
+		if (mch_stat((char *)swap_fname, &swap_st) >= 0
+			&& st.st_gid != swap_st.st_gid
+			&& fchown(curbuf->b_ml.ml_mfp->mf_fd, -1, st.st_gid)
+									 == -1)
+		    swap_mode &= 0600;
+	    }
+
+	    (void)mch_setperm(swap_fname, (long)swap_mode);
+	}
 #endif
     }
 
diff --git a/src/version.c b/src/version.c
index a5cb078f0..5c0df475f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1263,
+/**/
     983,
 /**/
     982,
-- 
2.11.0