entries in PT_DYNAMIC section refer to the correct address at runtime?

Yubin Ruan ablacktshirt@gmail.com
Thu Sep 14 04:09:00 GMT 2017


I read the ELF spec and note that, a segment designated by a program
header of type PT_DYNAMIC have several entries, many of which contain
addresses of other things. For example, an entry of type DT_SYMTAB was
described (in the ELF) spec to "holds the address of the symbol
table". I wonder whether this address is true at runtime?

Normally a program header would have the following structure:

typedef struct {
    Elf32_Word  p_type;
    Elf32_Off   p_offset;
    Elf32_Addr  p_vaddr;
    Elf32_Addr  p_paddr;
    Elf32_Word  p_filesz;
    Elf32_Word  p_memsz;
    Elf32_Word  p_flags;
    Elf32_Word  p_align;
} Elf32_Phdr;

The `p_vaddr` hold the virtual address (runtime address) for a shared
object file and a executable file. But, as stated in the ELF spec,
`p_vaddr` might not be correct for a shared object (because it is
required to be PIC). So, if that `p_vaddr` is not correct, will those
entries in PT_DYNAMIC be correct?


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