[openssl-commits] [openssl] OpenSSL_1_1_0-stable update

[Andy Polyakov]

The branch OpenSSL_1_1_0-stable has been updated
       via  d3d51adc87137fec7472a7e741490622ce725671 (commit)
      from  913d3a644edafee2a20c620e8625e9f3be49f643 (commit)


- Log -----------------------------------------------------------------
commit d3d51adc87137fec7472a7e741490622ce725671
Author: Andy Polyakov <appro at openssl.org>
Date:   Fri Apr 28 10:06:35 2017 +0200

    asn1/a_int.c: fix "next negative minimum" corner case in c2i_ibuf.
    
    "Next" refers to negative minimum "next" to one presentable by given
    number of bytes. For example, -128 is negative minimum presentable by
    one byte, and -256 is "next" one.
    
    Thanks to Kazuki Yamaguchi for report, GH#3339
    
    Reviewed-by: Rich Salz <rsalz at openssl.org>
    Reviewed-by: Richard Levitte <levitte at openssl.org>
    (cherry picked from commit 1e93d619b78832834ae32f5c0c1b0e466267f72d)

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

Summary of changes:
 crypto/asn1/a_int.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/crypto/asn1/a_int.c b/crypto/asn1/a_int.c
index e154343..217650a 100644
--- a/crypto/asn1/a_int.c
+++ b/crypto/asn1/a_int.c
@@ -167,10 +167,21 @@ static size_t c2i_ibuf(unsigned char *b, int *pneg,
         }
         return 1;
     }
-    if (p[0] == 0 || p[0] == 0xFF)
+
+    pad = 0;
+    if (p[0] == 0) {
         pad = 1;
-    else
-        pad = 0;
+    } else if (p[0] == 0xFF) {
+        size_t i;
+
+        /*
+         * Special case [of "one less minimal negative" for given length]:
+         * if any other bytes non zero it was padded, otherwise not.
+         */
+        for (pad = 0, i = 1; i < plen; i++)
+            pad |= p[i];
+        pad = pad != 0 ? 1 : 0;
+    }
     /* reject illegal padding: first two octets MSB can't match */
     if (pad && (neg == (p[1] & 0x80))) {
         ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_PADDING);