SquashFS iteration fails with "unexpected EOF"

[tri-adam]

What happened:

When iterating through a SquashFS layer within particular SIF images, an error is encountered. The image described in anchore/syft#1150 is one example of this.

What you expected to happen:

Expected SquashFS iteration to succeed with well-formed SIF images.

How to reproduce it (as minimally and precisely as possible):

Install SingularityCE and build a SIF:

singularity build OneAPI.sif docker://intel/oneapi-hpckit:latest

Process with stereoscope:

$ go run examples/basic.go singularity:OneAPI.sif 
DEBU[0000] image: source=Singularity location=OneAPI.sif 
DEBU[0015] image metadata: digest=sha256:2f58e7c87a19782f3f459bd8db1393fb37740a38e78957228200a753d31de312 mediaType=application/vnd.sylabs.sif.layer.v1.sif tags=[] 
DEBU[0015] layer metadata: index=0 digest=sha256:11cc80431c3b72354f0a2c551508592b874579be91ab23a75343037f6a44f93e mediaType=application/vnd.sylabs.sif.layer.v1.squashfs 
panic: could not read image: failed to walk layer="sha256:11cc80431c3b72354f0a2c551508592b874579be91ab23a75343037f6a44f93e": open opt/intel/oneapi/compiler/2022.1.0/linux/lib/oclfpga/host/linux64/bin/perl/lib/5.30.3/pod/perlpod.pod: unexpected EOF

goroutine 1 [running]:
main.main()
        /home/adam/src/stereoscope/examples/basic.go:32 +0x73b
exit status 2

Anything else we need to know?:

The error occurs with or without the patch from #139 applied, so I believe this issue is distinct from #138.

Environment:

$ cat /etc/os-release 
PRETTY_NAME="Ubuntu 22.04.1 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.1 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

$ singularity --version
singularity-ce version 3.10.2

[tri-adam]

With the patch to the squashfs module (CalebQ42/squashfs#15 applied), I can confirm stereoscope is able to iterate a SIF built from docker://intel/oneapi-hpckit:latest.

Once the underlying issue is fixed in a tagged release, I'll open a PR to update the squashfs module and close this issue.