[Bug malloc/25947] New: memory leak in muntrace

[Bug malloc/25947] New: memory leak in muntrace

[wangxuszcn at foxmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=25947

            Bug ID: 25947
           Summary: memory leak in muntrace
           Product: glibc
           Version: 2.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: malloc
          Assignee: unassigned at sourceware dot org
          Reporter: wangxuszcn at foxmail dot com
  Target Milestone: ---

Since glibc 2.32, stream buffer used by mallstream in mtrace() function, should
be freed in muntrace(), or 512 byte will leaked every call of mtrace().


Patches can be like this:
diff --git a/malloc/mtrace.c b/malloc/mtrace.c
index 7e7719d..b3bc5b0 100644
--- a/malloc/mtrace.c
+++ b/malloc/mtrace.c
@@ -365,4 +365,5 @@ muntrace (void)

   fprintf (f, "= End\n");
   fclose (f);
+  free (malloc_trace_buffer);
 }

Will any one request a CVE for this issue?

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[Bug malloc/25947] memory leak in muntrace

[fw at deneb dot enyo.de]

https://sourceware.org/bugzilla/show_bug.cgi?id=25947

Florian Weimer <fw at deneb dot enyo.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-05-08
                 CC|                            |fw at deneb dot enyo.de

--- Comment #1 from Florian Weimer <fw at deneb dot enyo.de> ---
Do you have a concrete application where this leads to a denial of service (in
non-debugging mode)?

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[Bug malloc/25947] memory leak in muntrace

[wangxuszcn at foxmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=25947

--- Comment #2 from wangxu <wangxuszcn at foxmail dot com> ---
Thanks for reply.
Actually, I have not. Just consider the situation that application A call
mtrace/muntrace to trace malloc frequently, 512 byte physical memory(virtual
memory may be more) will leaked everytime.
When runing out of its memory quota, A will be killed because of OOM.

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[Bug malloc/25947] memory leak in muntrace

[fw at deneb dot enyo.de]

https://sourceware.org/bugzilla/show_bug.cgi?id=25947

Florian Weimer <fw at deneb dot enyo.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
              Flags|                            |security-

--- Comment #3 from Florian Weimer <fw at deneb dot enyo.de> ---
In this case, let's treat this as a regular bug.

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[Bug malloc/25947] memory leak in muntrace

[siddhesh at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25947

Siddhesh Poyarekar <siddhesh at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |2.35
                 CC|                            |siddhesh at sourceware dot org
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #4 from Siddhesh Poyarekar <siddhesh at sourceware dot org> ---
commit dc906e94f7033892dadbd91718349f19e1376391
Author: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date:   Thu Aug 12 06:38:15 2021 +0530

    mtrace: Use a static buffer for printing [BZ #25947]

    Use a static buffer for mtrace printing now that it no longer adds to
    default libc footprint.

    Reviewed-by: DJ Delorie <dj@redhat.com>

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