Bug#773000: dumpasn1: slow on crafted input

[Jakub Wilk]

Package: dumpasn1
Version: 20130608-1
Severity: minor
Usertags: afl



$ time dumpasn1 -s slow.der
0 warnings, 2 errors.

real    0m9.955s
user    0m2.644s
sys     0m7.252s




read(3, "", 4096)                       = 0
read(3, "", 4096)                       = 0
read(3, "", 4096)                       = 0
[... and so on, literally millions times...]


This bug was found using American fuzzy lop:
https://packages.debian.org/experimental/afl

-- System Information:
Debian Release: 8.0
 APT prefers unstable
 APT policy: (990, 'unstable'), (500, 'experimental')
Architecture: i386 (x86_64)
Foreign Architectures: amd64

Kernel: Linux 3.2.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=C, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages dumpasn1 depends on:
ii  libc6  2.19-13

--
Jakub Wilk

dumpasn1 is super slow while verifying this 5-bytes-long crafted input file: strace tells me that the program was busy reading the input file past EOF:

slow.der
Description: application/pkix-cert