[Bug nscd/31677] New: nscd: negroup cache: invalid memcpy under low memory/storage conditions

[Bug nscd/31677] New: nscd: negroup cache: invalid memcpy under low memory/storage conditions

[carlos at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

            Bug ID: 31677
           Summary: nscd: negroup cache: invalid memcpy under low
                    memory/storage conditions
           Product: glibc
           Version: 2.40
            Status: NEW
          Severity: normal
          Priority: P2
         Component: nscd
          Assignee: unassigned at sourceware dot org
          Reporter: carlos at redhat dot com
                CC: drepper.fsp at gmail dot com
  Target Milestone: ---

nscd/netgroupcache.c (addinnetgrX):

497   struct indataset
498   {
499     struct datahead head;
500     innetgroup_response_header resp;
501   } *dataset
502       = (struct indataset *) mempool_alloc (db,
503                                             sizeof (*dataset) +
req->key_len,
504                                             1);

mempool_alloc fails and returns NULL.

This is possible if posix_fallocate fails and the retry fails.

505   struct indataset dataset_mem;
506   bool cacheable = true;
507   if (__glibc_unlikely (dataset == NULL))
508     {
509       cacheable = false;
510       dataset = &dataset_mem;

This structure has no room for req->key_len material.

511     }
512 
513   datahead_init_pos (&dataset->head, sizeof (*dataset) + req->key_len,
514                      sizeof (innetgroup_response_header),
515                      he == NULL ? 0 : dh->nreloads + 1, result->head.ttl);
516   /* Set the notfound status and timeout based on the result from
517      getnetgrent.  */
518   dataset->head.notfound = result->head.notfound;
519   dataset->head.timeout = timeout;
520 
521   dataset->resp.version = NSCD_VERSION;
522   dataset->resp.found = result->resp.found;
523   /* Until we find a matching entry the result is 0.  */
524   dataset->resp.result = 0;
525 
526   char *key_copy = memcpy ((char *) (dataset + 1), group, req->key_len);

This copies up to req->key_len material to a structure that has no storage
space for it.

This was detected by static code analysis.

It will only happen in the case the database runs out of memory/storage while
expanding the netgroup cache.

The group entries overwrite other data on the stack after dataset_mem.

The workaround is not to cache the netgroup if this is impacting the use of the
application.

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[Bug nscd/31677] nscd: negroup cache: invalid memcpy under low memory/storage conditions

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fweimer at redhat dot com
              Flags|                            |security+

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[Bug nscd/31677] nscd: negroup cache: invalid memcpy under low memory/storage conditions

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at sourceware dot org   |fweimer at redhat dot com
             Status|NEW                         |ASSIGNED

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[Bug nscd/31677] nscd: netgroup cache: invalid memcpy under low memory/storage conditions

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|nscd: negroup cache:        |nscd: netgroup cache:
                   |invalid memcpy under low    |invalid memcpy under low
                   |memory/storage conditions   |memory/storage conditions

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[Bug nscd/31677] nscd: netgroup cache: invalid memcpy under low memory/storage conditions

[carlos at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

Carlos O'Donell <carlos at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Alias|                            |CVE-2024-33599

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[Bug nscd/31677] nscd: netgroup cache: invalid memcpy under low memory/storage conditions

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |2.40
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #1 from Florian Weimer <fweimer at redhat dot com> ---
Fixed for glibc 2.40 via:

commit 87801a8fd06db1d654eea3e4f7626ff476a9bdaa
Author: Florian Weimer <fweimer@redhat.com>
Date:   Thu Apr 25 15:00:45 2024 +0200

    CVE-2024-33599: nscd: Stack-based buffer overflow in netgroup cache (bug
31677)

    Using alloca matches what other caches do.  The request length is
    bounded by MAXKEYLEN.

    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

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[Bug nscd/31677] nscd: netgroup cache: invalid memcpy under low memory/storage conditions

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sam at gentoo dot org

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[Bug nscd/31677] nscd: netgroup cache: invalid memcpy under low memory/storage conditions

[carnil at debian dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31677

Salvatore Bonaccorso <carnil at debian dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |carnil at debian dot org

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