From fa741771ed47b30547be63b5b5dbfb51977aca12 Mon Sep 17 00:00:00 2001 From: Chet Ramey Date: Fri, 20 Jan 2017 11:47:31 -0500 Subject: [PATCH] Bash-4.4 patch 6 Bug-Reference-URL: https://lists.gnu.org/archive/html/bug-bash/2016-11/msg00116.html Reference to upstream patch: https://ftp.gnu.org/pub/gnu/bash/bash-4.4-patches/bash44-006 Bug-Description: Out-of-range negative offsets to popd can cause the shell to crash attempting to free an invalid memory block. Upstream-Status: Backport CVE: CVE-2016-9401 Signed-off-by: Li Zhou --- builtins/pushd.def | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/builtins/pushd.def b/builtins/pushd.def index 9c6548f..8a13bae 100644 --- a/builtins/pushd.def +++ b/builtins/pushd.def @@ -359,7 +359,7 @@ popd_builtin (list) break; } - if (which > directory_list_offset || (directory_list_offset == 0 && which == 0)) + if (which > directory_list_offset || (which < -directory_list_offset) || (directory_list_offset == 0 && which == 0)) { pushd_error (directory_list_offset, which_word ? which_word : ""); return (EXECUTION_FAILURE); @@ -381,6 +381,11 @@ popd_builtin (list) remove that directory from the list and shift the remainder of the list into place. */ i = (direction == '+') ? directory_list_offset - which : which; + if (i < 0 || i > directory_list_offset) + { + pushd_error (directory_list_offset, which_word ? which_word : ""); + return (EXECUTION_FAILURE); + } free (pushd_directory_list[i]); directory_list_offset--; -- 1.9.1