debian/patches/79_02-Rework-SPA-fix-to-avoid-overflows.-Bug-2571.patch

   1 From 5a41d2c2cd2b28a0d1aea21edeaea02bd6db4984 Mon Sep 17 00:00:00 2001
   2 From: Jeremy Harris <jgh146exb@wizmail.org>
   3 Date: Wed, 6 May 2020 22:31:25 +0100
   4 Subject: [PATCH 2/2] Rework SPA fix to avoid overflows.  Bug 2571
   5
   6 Amends: 6a7edbf660
   7 (cherry picked from commit a04174dc2a84ae1008c23b6a7109e7fa3fb7b8b0)
   8 ---
   9  src/auths/spa.c | 13 +++++++++----
  10  1 file changed, 9 insertions(+), 4 deletions(-)
  11
  12 diff --git a/src/auths/spa.c b/src/auths/spa.c
  13 index ed9aff23b..4e3aef808 100644
  14 --- a/src/auths/spa.c
  15 +++ b/src/auths/spa.c
  16 @@ -140,6 +140,7 @@ SPAAuthResponse  response;
  17  SPAAuthResponse  *responseptr = &response;
  18  uschar msgbuf[2048];
  19  uschar *clearpass, *s;
  20 +unsigned off;
  21
  22  /* send a 334, MS Exchange style, and grab the client's request,
  23  unless we already have it via an initial response. */
  24 @@ -194,10 +195,13 @@ that causes failure if the size of msgbuf is exceeded. ****/
  25
  26    {
  27    int i;
  28 -  char *p = ((char*)responseptr) + IVAL(&responseptr->uUser.offset,0);
  29 +  char * p;
  30    int len = SVAL(&responseptr->uUser.len,0)/2;
  31
  32 -  if (p + len*2 >= CS (responseptr+1))
  33 +  if (  (off = IVAL(&responseptr->uUser.offset,0)) >= sizeof(SPAAuthResponse)
  34 +     || len >= sizeof(responseptr->buffer)/2
  35 +     || (p = (CS responseptr) + off) + len*2 >= CS (responseptr+1)
  36 +     )
  37      {
  38      DEBUG(D_auth)
  39        debug_printf("auth_spa_server(): bad uUser spec in response\n");
  40 @@ -252,13 +256,14 @@ spa_smb_nt_encrypt (clearpass, challenge.challengeData, ntRespData);
  41
  42  /* compare NT hash (LM may not be available) */
  43
  44 -s = (US responseptr) + IVAL(&responseptr->ntResponse.offset,0);
  45 -if (s + 24 >= US (responseptr+1))
  46 +off = IVAL(&responseptr->ntResponse.offset,0);
  47 +if (off >= sizeof(SPAAuthResponse) - 24)
  48    {
  49    DEBUG(D_auth)
  50      debug_printf("auth_spa_server(): bad ntRespData spec in response\n");
  51    return FAIL;
  52    }
  53 +s = (US responseptr) + off;
  54
  55  if (memcmp(ntRespData, s, 24) == 0)
  56    return auth_check_serv_cond(ablock); /* success. we have a winner. */
  57 --
  58 2.26.2
  59