This is the mail archive of the mailing list for the binutils project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: dynrelro section for read-only dynamic symbols copied into executable

On Sun, 25 Dec 2016 21:44:48 PST (-0800), wrote:
> riscv scripts are hosed for -z relro.

Andrew and I can't figure out why relro is broken on RISC-V.  I looked at our
linker scripts (via riscv64-unknown-linux-gnu-gcc -Wl,-verbose) and the
section looks the same as on my x86 machine, and it's in a similar order to the
x86 one (the got has moved a bit, but there's a comment for why it's in a
slightly different place).  Additionally, I readelf'd some arbitrary executable
and it appears that the GNU_RELRO segment is read-only

  $ riscv64-unknown-linux-gnu-readelf -l install/sysroot/usr/bin/locale

  Elf file type is EXEC (Executable file)
  Entry point 0x168a4
  There are 9 program headers, starting at offset 64

  Program Headers:
    Type           Offset             VirtAddr           PhysAddr
                   FileSiz            MemSiz              Flags  Align
    PHDR           0x0000000000000040 0x0000000000010040 0x0000000000010040
                   0x00000000000001f8 0x00000000000001f8  R E    0x8
    INTERP         0x0000000000000238 0x0000000000010238 0x0000000000010238
                   0x0000000000000014 0x0000000000000014  R      0x1
        [Requesting program interpreter: /lib64/lp64/]
    LOAD           0x0000000000000000 0x0000000000010000 0x0000000000010000
                   0x00000000000039b4 0x00000000000039f8  RW     0x1000
    LOAD           0x00000000000039f8 0x00000000000149f8 0x00000000000149f8
                   0x00000000000047e4 0x00000000000047e4  R E    0x1000
    LOAD           0x0000000000008e00 0x000000000001ae00 0x000000000001ae00
                   0x0000000000000438 0x0000000000000438  RW     0x1000
    DYNAMIC        0x0000000000008e20 0x000000000001ae20 0x000000000001ae20
                   0x00000000000001e0 0x00000000000001e0  RW     0x8
    NOTE           0x000000000000024c 0x000000000001024c 0x000000000001024c
                   0x0000000000000020 0x0000000000000020  R      0x4
    GNU_EH_FRAME   0x0000000000008194 0x0000000000019194 0x0000000000019194
                   0x0000000000000014 0x0000000000000014  R      0x4
    GNU_RELRO      0x0000000000008e00 0x000000000001ae00 0x000000000001ae00
                   0x0000000000000200 0x0000000000000200  R      0x1

   Section to Segment mapping:
    Segment Sections...
     01     .interp
     02     .interp .note.ABI-tag .data .rodata .sdata .sbss .bss
     03     .hash .gnu.hash .dynsym .dynstr .gnu.version .gnu.version_r .rela.dyn .rela.plt .plt .text .eh_frame_hdr .eh_frame
     04     .preinit_array .init_array .fini_array .jcr .dynamic .got
     05     .dynamic
     06     .note.ABI-tag
     07     .eh_frame_hdr
     08     .preinit_array .init_array .fini_array .jcr .dynamic

I saw your metage relro patch go by, but we have COMMONPAGESIZE so I don't
think that's the problem.

Can you (or anyone else) offer a hint?  We'd love to get this fixed, we just
didn't know about the problem.

Thanks for the heads up!

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]