From cecb762fc3fb91e121a3f64d147fdf6b5aa7477e Mon Sep 17 00:00:00 2001
From: Andrei Lascu <andrei.lascu@kcl.ac.uk>
Date: Fri, 19 Jul 2024 14:31:52 +0100
Subject: [PATCH] Bug fix

* Fix a bug with relocating against other external symbols
* Enable 1.33 tests (one `lua` test from the suite passing)
---
 include/compartment.h |  1 +
 src/compartment.c     | 10 ++++------
 tests/CMakeLists.txt  |  2 +-
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/include/compartment.h b/include/compartment.h
index 7af4dcc..bf4976d 100644
--- a/include/compartment.h
+++ b/include/compartment.h
@@ -106,6 +106,7 @@ struct LibDependencySymbol
     void *sym_offset;
     unsigned short sym_type;
     unsigned short sym_bind;
+    uint16_t sym_shndx;
 };
 
 /* Struct representing the result of searching for a library symbol in a
diff --git a/src/compartment.c b/src/compartment.c
index 5672a28..ef6e27d 100644
--- a/src/compartment.c
+++ b/src/compartment.c
@@ -657,6 +657,7 @@ parse_lib_symtb(Elf64_Shdr *symtb_shdr, Elf64_Ehdr *lib_ehdr, int lib_fd,
         strcpy(ld_syms[actual_syms].sym_name, sym_name);
         ld_syms[actual_syms].sym_type = ELF64_ST_TYPE(curr_sym.st_info);
         ld_syms[actual_syms].sym_bind = ELF64_ST_BIND(curr_sym.st_info);
+        ld_syms[actual_syms].sym_shndx = curr_sym.st_shndx;
         actual_syms += 1;
     }
     ld_syms
@@ -1080,18 +1081,15 @@ find_lib_dep_sym_in_lib(const char *to_find, struct Compartment *comp_to_search,
         // Ignore `LOCAL` bind symbols - they cannot be relocated against
         bool cond = curr_sym.sym_bind != STB_LOCAL;
 
+        // Check symbol is indeed local, not another external reference
+        cond = cond && curr_sym.sym_shndx != 0;
+
         // Check symbol name matches
         cond = cond && !strcmp(to_find, curr_sym.sym_name);
 
         // Check symbol type matches
         cond = cond && curr_sym.sym_type == sym_type;
 
-        // Symbols cannot have 0-offset values (except if they are a TLS symbol)
-        if (sym_type != STT_TLS)
-        {
-            cond = cond && curr_sym.sym_offset != 0;
-        }
-
         // If all conditions pass, we found a valid symbol to relocate against
         if (cond)
         {
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 8fd7611..6489588 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -177,7 +177,7 @@ set(tests
     "simple_syscall_write"
     "simple_thrloc_var"
     "simple_time"
-    #"simple_toupper"
+    "simple_toupper"
     "simple_va_args"
     "tls_check"