[COMMITTED 2.24 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         | 4 ++++
 posix/glob.c | 2 +-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 7d47dd8d7d..5229661ab1 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 9a9e487ee6..8c10e88ec5 100644
--- a/NEWS
+++ b/NEWS
@@ -21,6 +21,10 @@ Security related changes:
   question type which is outside the range of valid question type values.
   (CVE-2015-5180)
 
+* 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).
+
 The following bugs are resolved with this release:
 
   [20790] Fix rpcgen buffer overrun
diff --git a/posix/glob.c b/posix/glob.c
index ea6a240209..026bc063d3 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -883,7 +883,7 @@ 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