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From: Pavel Raiskup

Subject: [Bug-cpio] [PATCH] fix 1-byte out-of-bounds write

Date: Tue, 26 Jan 2016 23:17:54 +0100

​

Other calls to cpio_safer_name_suffix seem to be safe.

​

* src/copyin.c (process_copy_in):  Make sure that file_hdr.c_name

has at least two bytes allocated.

* src/util.c (cpio_safer_name_suffix): Document that use of this

function requires to be careful.

​

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>

---

Patch status: fetched/submitted

URL: https://lists.gnu.org/archive/html/bug-cpio/2016-01/msg00005.html

​

 src/copyin.c | 2 ++

 src/util.c   | 5 ++++-

 2 files changed, 6 insertions(+), 1 deletion(-)

​

diff --git a/src/copyin.c b/src/copyin.c

index cde911e..032d35f 100644

--- a/src/copyin.c

+++ b/src/copyin.c

@@ -1385,6 +1385,8 @@ process_copy_in ()

          break;

        }

​

+      if (file_hdr.c_namesize <= 1)

+        file_hdr.c_name = xrealloc(file_hdr.c_name, 2);

       cpio_safer_name_suffix (file_hdr.c_name, false, !no_abs_paths_flag,

                              false);

​

diff --git a/src/util.c b/src/util.c

index 6ff6032..2763ac1 100644

--- a/src/util.c

+++ b/src/util.c

@@ -1411,7 +1411,10 @@ set_file_times (int fd,

 }

 /* Do we have to ignore absolute paths, and if so, does the filename

-   have an absolute path?  */

+   have an absolute path?

+   Before calling this function make sure that the allocated NAME buffer has

+   capacity at least 2 bytes to allow us to store the "." string inside.  */

+

 void

 cpio_safer_name_suffix (char *name, bool link_target, bool absolute_names,

                        bool strip_leading_dots)

--

2.5.0