[Bug binutils/5037] New: strip shrinks PT_GNU_RELRO on PIE objects

[vapier at gentoo dot org]

using gcc-3.4.6 and building a PIE binary with -z relro results in an ELF that,
when stripped, causes the PT_GNU_RELRO to shrink the memsize more than the
filesize ... perhaps this is a dupe of Bug 3281 ...

$ gcc-3.4.6 dumpelf.c -o dumpelf -fPIE -Wl,-z,relro
$ readelf -Wl dumpelf | grep GNU_REL
GNU_RELRO 0x007d50 0x00607d50 0x00607d50 0x0002b0 0x0002b0 R 0x1
$ strip dumpelf
$ readelf -Wl dumpelf | grep GNU_REL
GNU_RELRO 0x007d50 0x00607d50 0x00607d50 0x000288 0x000280 R 0x1

the filesize (0x288) is larger than the memsize (0x280)

looking at the relevant section headers:
[17] .ctors         PROGBITS   00607d50 007d50 000010 00  WA  0   0  8
[18] .dtors         PROGBITS   00607d60 007d60 000010 00  WA  0   0  8
[19] .jcr           PROGBITS   00607d70 007d70 000008 00  WA  0   0  8
[20] .data.rel.ro   PROGBITS   00607d80 007d80 0000a0 00  WA  0   0 32
[21] .dynamic       DYNAMIC    00607e20 007e20 000190 10  WA  5   0  8
[22] .got           PROGBITS   00607fb0 007fb0 000028 08  WA  0   0  8

we see the filesize of the PT is correct (0x7d50 + 0x288 covers all these
sections) but the memsize of the PT does not include the last few entries of the
.got (0x7d50 + 0x280 is 0x8 bytes short of the end of the .got)

-- 
           Summary: strip shrinks PT_GNU_RELRO on PIE objects
           Product: binutils
           Version: 2.18
            Status: NEW
          Severity: normal
          Priority: P2
         Component: binutils
        AssignedTo: unassigned at sources dot redhat dot com
        ReportedBy: vapier at gentoo dot org
                CC: bug-binutils at gnu dot org
  GCC host triplet: x86_64-linux-gnu


http://sourceware.org/bugzilla/show_bug.cgi?id=5037

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