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Add detection for relative dynamic table addresses

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This commit is contained in:
Kasper Sauramo
2025-03-20 11:55:09 +02:00
parent 1f10b3b821
commit 32c7d794f1
4 changed files with 36 additions and 48 deletions
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57
src/symbols.c
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@@ -12,6 +12,14 @@
#include <stdlib.h>
#include <string.h>
static inline uptr
add_ptr_offset_if_invalid(uptr p, uptr offset,
struct sc_array_memreg *const regions) {
if (memory_find_pointer(p, regions, NULL) != HILOAD_OK)
return p + offset;
return p;
}
/**
* Gathers and populates symbols, given a dynamic module info
*
@@ -51,13 +59,14 @@ CreateResult hi_create_symbol_info(SymbolInfos *symbols,
size_t strtab_size = 0;
uptr off = info->dlpi_addr;
// Parse the dynamic table
// Parse the dynamic table. Add offset if address is not in executable memory.
// NOTE: Haven't found a better way to differentiate with items that have
// relative address, and items that don't.
for (; dyn->d_tag != DT_NULL; dyn++) {
if (dyn->d_tag == DT_STRTAB) {
uptr p = dyn->d_un.d_ptr;
if (!memory_find_pointer(p, regions, NULL))
p += off;
p = add_ptr_offset_if_invalid(p, off, regions);
strtab = (const char *)p;
} else if (dyn->d_tag == DT_STRSZ) {
@@ -65,8 +74,7 @@ CreateResult hi_create_symbol_info(SymbolInfos *symbols,
} else if (dyn->d_tag == DT_SYMTAB) {
uptr p = dyn->d_un.d_ptr;
if (!memory_find_pointer(p, regions, NULL))
p += off;
p = add_ptr_offset_if_invalid(p, off, regions);
symtab = (const ElfW(Sym) *)(p);
} else if (dyn->d_tag == DT_SYMENT) {
@@ -76,25 +84,11 @@ CreateResult hi_create_symbol_info(SymbolInfos *symbols,
// Ensure we found the symbol and string tables
if (!strtab || !symtab || strtab_size == 0 || symtab_size == 0) {
fprintf(stderr, "Failed to find symbol or string table in %s\n",
sc_log_error("Failed to find symbol or string table in %s\n",
info->dlpi_name);
return CREATE_FAILED;
}
symbols->capacity = symtab_size / sizeof(char);
symbols->names = calloc(symbols->capacity, sizeof(char *));
if (!symbols->names) {
fprintf(stderr, "Failed to allocate memory for symbol names.\n");
return CREATE_FAILED;
}
symbols->addresses = calloc(symbols->capacity, sizeof(void *));
if (!symbols->addresses) {
fprintf(stderr, "Failed to allocate memory for symbol addresses.\n");
return CREATE_FAILED;
}
// Iterate over the symbol table
for (const ElfW(Sym) *sym = symtab;
(const char *)sym < (const char *)symtab + symtab_size; sym++) {
@@ -103,15 +97,9 @@ CreateResult hi_create_symbol_info(SymbolInfos *symbols,
const char *name = strdup(&strtab[sym->st_name]);
void *address = (void *)(info->dlpi_addr + sym->st_value);
// Store the symbol information in the struct of arrays
if (symbols->count < symbols->capacity) {
symbols->names[symbols->count] = (char *)name;
symbols->addresses[symbols->count] = address;
symbols->count++;
} else {
fprintf(stderr, "Symbol table capacity exceeded!\n");
return CREATE_FAILED;
}
// Store the symbol information in the arrays
sc_array_add(&symbols->names, name);
sc_array_add(&symbols->addresses, address);
}
}
}
@@ -120,11 +108,10 @@ CreateResult hi_create_symbol_info(SymbolInfos *symbols,
}
void hi_free_symbol_info(SymbolInfos *symbols) {
for (size_t i = 0; i < symbols->count; i++) {
free(symbols->names[i]);
for (size_t i = 0; i < symbols->names.size; i++) {
free((void *)symbols->names.elems[i]);
}
free(symbols->names);
free(symbols->addresses);
symbols->count = 0;
symbols->capacity = 0;
sc_array_term(&symbols->names);
sc_array_term(&symbols->addresses);
}