Fix issue 370

The issue gets triggered, because qemu/virsh generated elf dump contains strtab
at the end of the dump file. Meanwhile, dumps are large, and thus, it is
infeasible to provide the entire dump file to the parser. This PR relaxes the
requirements of the parser and returns default strtab, if the initial size
check fails.

src/elf/mod.rs

@@ -70,6 +70,7 @@ if_sylvan! {
     use crate::container::{Container, Ctx};
     use alloc::vec::Vec;
     use core::cmp;
+    use log::warn;
 
     pub use header::Header;
     pub use program_header::ProgramHeader;
@@ -286,12 +287,19 @@ if_sylvan! {
                 }
 
                 if section_idx >= section_headers.len() {
-                    // FIXME: warn! here
+                    warn!("strtab section idx {} is out of bounds ({})", section_idx, section_headers.len());
                     Ok(Strtab::default())
                 } else {
                     let shdr = &section_headers[section_idx];
-                    shdr.check_size(bytes.len())?;
-                    Strtab::parse(bytes, shdr.sh_offset as usize, shdr.sh_size as usize, 0x0)
+                    // If size check fails, that means strtab is outside user supplied buffer. We
+                    // can either hard-fail there, or return an empty strtab. The latter is less
+                    // disturbing.
+                    if shdr.check_size(bytes.len()).is_ok() {
+                        Strtab::parse(bytes, shdr.sh_offset as usize, shdr.sh_size as usize, 0x0)
+                    } else {
+                        warn!("strtab section goes outside the provided buffer");
+                        Ok(Strtab::default())
+                    }
                 }
             };