Determine if an ELF file is signed or not

Question

I need some help in determining if an ELF file is signed or with a valid signature or not.

I have used the readelf tool with -S option in order to view the section headers and more specifically, the sig section header. This is the result I got:

[30] .sha256_sig         PROGBITS         00000000000000000  00023276
[31] .sig_key            PROGBITS         00000000000000000  00023676

Few questions:

1. Since there are two headers (sha256_sig and sig_key), does this mean the ELF is signed?
2. How can I verify the signature?

Answer 1

The -S flag lists all section headers, not "sig[nature] section header". The S stands for "sections", not "signature".

Moreover, these section names appear to be quite unrelated to linux itself, but are part of the linux AppImage application, a third party application framework that includes it's own signed update mechanism. The only references I could find to these section names are part of it's update mechanism as can be seen in this Pull Request.