[COMMITTED 2.25 3/8] CVE-2017-15670: glob: Fix one-byte overflow [BZ #22320]

[Aurelien Jarno]

From: Paul Eggert <eggert@cs.ucla.edu>

(cherry picked from commit c369d66e5426a30e4725b100d5cd28e372754f90)
---
 ChangeLog    | 6 ++++++
 NEWS         | 7 +++++++
 posix/glob.c | 2 +-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index f9ea53f23e..44eb9d7d7c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-20  Paul Eggert <eggert@cs.ucla.edu>
+
+	[BZ #22320]
+	CVE-2017-15670
+	* posix/glob.c (__glob): Fix one-byte overflow.
+
 2017-09-08  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
 	[BZ #1062]
diff --git a/NEWS b/NEWS
index 1879b735e6..98aa362444 100644
--- a/NEWS
+++ b/NEWS
@@ -29,6 +29,13 @@ The following bugs are resolved with this release:
   [21778] Robust mutex may deadlock
   [21972] assert macro requires operator== (int) for its argument type
   [22322] libc: [mips64] wrong bits/long-double.h installed
+
+Security related changes:
+
+  CVE-2017-15670: The glob function, when invoked with GLOB_TILDE, suffered
+  from a one-byte overflow during ~ operator processing (either on the stack
+  or the heap, depending on the length of the user name).
+
 
 Version 2.25
 
diff --git a/posix/glob.c b/posix/glob.c
index a7eccf9cb4..c761c0861d 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -870,7 +870,7 @@ glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
 		  *p = '\0';
 		}
 	      else
-		*((char *) mempcpy (newp, dirname + 1, end_name - dirname))
+		*((char *) mempcpy (newp, dirname + 1, end_name - dirname - 1))
 		  = '\0';
 	      user_name = newp;
 	    }
-- 
2.15.0