486060 - sec_asn1d_parse_leaf uses argument uninitialized by caller pbe_PK11AlgidToParam

Status: RESOLVED FIXED

(NSS :: Libraries, defect, P3)

Description

[Nelson Bolyard (seldom reads bugmail)]

Attachment: Patch v1 for NSS Trunk (untested)

This bug was reported in bug 447882 comment 13 by 
Rich Megginson <[e-mail]>

Some code paths in pbe_PK11AlgidToParam call SEC_ASN1DecodeItem without
first initializing (zeroing) the structure that will receive the output.
This occasionally leads to a crash in sec_asn1d_parse_leaf due to a 
an uninitialized SECItem structure that has a non-null data pointer,
which is not the result of the parser.

Rich suggests the attached patch should fix it.  I'd like to have steps
to reproduce.

Comment 1

[Robert Relyea]

Comment on attachment 370138 [details] [diff] [review]
Patch v1 for NSS Trunk (untested)

r+ looks safe

Comment 2

[Rich Megginson]

Note that this doesn't cause a crash, at least none that I saw.  valgrind reports it as "Conditional jump or move depends on uninitialised value(s)" at line 1561 (which probably includes 1562 and 1563) in secasn1d.c:
http://mxr.mozilla.org/mozilla/source/security/nss/lib/util/secasn1d.c#1561
1560         /* Strip leading zeroes when target is unsigned integer */
1561         if (state->underlying_kind == SEC_ASN1_INTEGER && /* INTEGER   */
1562             item->len == 0 &&                             /* MSB       */
1563             item->type == siUnsignedInteger)              /* unsigned  */

Comment 3

[Nelson Bolyard (seldom reads bugmail)]

Checking in pk11wrap/pk11pbe.c; new revision: 1.23; previous revision: 1.22