[openssl] OpenSSL_1_1_1-stable update

[bernd.edlinger at hotmail.de]

The branch OpenSSL_1_1_1-stable has been updated
       via  e6a80cbad28ee748830815634917efe96948f2f3 (commit)
      from  315170f662b3053aa9fe817639e1b78f74f75077 (commit)


- Log -----------------------------------------------------------------
commit e6a80cbad28ee748830815634917efe96948f2f3
Author: Bernd Edlinger <bernd.edlinger at hotmail.de>
Date:   Tue Jun 2 11:52:24 2020 +0200

    Fix a buffer overflow in drbg_ctr_generate
    
    This can happen if the 32-bit counter overflows
    and the last block is not a multiple of 16 bytes.
    
    Fixes #12012
    
    [extended tests]
    
    Reviewed-by: Tomas Mraz <tmraz at fedoraproject.org>
    Reviewed-by: Patrick Steuer <patrick.steuer at de.ibm.com>
    Reviewed-by: Kurt Roeckx <kurt at roeckx.be>
    (Merged from https://github.com/openssl/openssl/pull/12016)
    
    (cherry picked from commit 42fa3e66697baa121220b4eacf03607280e4ff89)

-----------------------------------------------------------------------

Summary of changes:
 crypto/rand/drbg_ctr.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/crypto/rand/drbg_ctr.c b/crypto/rand/drbg_ctr.c
index 89c9ccc876..a757d0a258 100644
--- a/crypto/rand/drbg_ctr.c
+++ b/crypto/rand/drbg_ctr.c
@@ -367,9 +367,11 @@ __owur static int drbg_ctr_generate(RAND_DRBG *drbg,
         ctr32 = GETU32(ctr->V + 12) + blocks;
         if (ctr32 < blocks) {
             /* 32-bit counter overflow into V. */
-            blocks -= ctr32;
-            buflen = blocks * 16;
-            ctr32 = 0;
+            if (ctr32 != 0) {
+                blocks -= ctr32;
+                buflen = blocks * 16;
+                ctr32 = 0;
+            }
             ctr96_inc(ctr->V);
         }
         PUTU32(ctr->V + 12, ctr32);