patchelf still corrupting binaries on mips64el-linux-gnuabin32

[ghost]

Even with the fixes in #82 and #180, it appears that patchelf --set-interpreter still corrupts binaries on MIPS.

The following is on an Octeon. Note that the argument passed to --set-interpeter has enough leading slashes to make it exactly the same length as the interpreter being replaced, so file offsets shifting around isn't the issue here.

I would have expected that only those bytes in the binary would change, but as the diff below shows, patchelf is changing lots of other stuff in the binary. In any case (see end of report) the resulting binary segfaults, whereas the original did not.

$ /tmp/patchelf/src/patchelf --version
patchelf 0.14.3
$ git -C /tmp/patchelf rev-parse HEAD
bdb09e90f75406068b061a69a3bde3878e5287fa
$ cp bash bash+
$ /tmp/patchelf/src/patchelf --set-interpreter /////////////////////////////////////////////////////////////////////////////tmp/q/lib/ld.so.1 bash+
$ readelf -a bash > bash.readelf
$ readelf -a bash+ > bash.readelf+
$ colordiff -u bash.readelf bash.readelf+
--- bash.readelf        2022-01-21 22:14:36.951398176 -0800
+++ bash.readelf+       2022-01-21 22:14:39.481427205 -0800
@@ -22,7 +22,7 @@
 Section Headers:
   [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
   [ 0]                   NULL            00000000 000000 000000 00      0   0  0
-  [ 1] .interp           PROGBITS        10000194 000194 00005f 00   A  0   0  1
+  [ 1] .interp           PROGBITS        10000194 000194 00005f 00   A  0   0  4
   [ 2] .note.ABI-tag     NOTE            100001f4 0001f4 000020 00   A  0   0  4
   [ 3] .MIPS.abiflags    MIPS_ABIFLAGS   10000218 000218 000018 18   A  0   0  8
   [ 4] .reginfo          MIPS_REGINFO    10000230 000230 000018 18   A  0   0  8
@@ -62,31 +62,31 @@
 Program Headers:
   Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
   PHDR           0x000034 0x10000034 0x10000034 0x00160 0x00160 R   0x4
+  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RWE 0x10
+  NULL           0x000000 0x00000000 0x00000000 0x00000 0x00000     0x4
+  LOAD           0x000000 0x10000000 0x10000000 0xd9194 0xd9194 R E 0x10000
   INTERP         0x000194 0x10000194 0x10000194 0x0005f 0x0005f R   0x1
-      [Requesting program interpreter: /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-glibc-mips64el-linux-gnuabin32-2.33-59/lib/ld.so.1]
+      [Requesting program interpreter: /////////////////////////////////////////////////////////////////////////////tmp/q/lib/ld.so.1]
+  NOTE           0x0001f4 0x100001f4 0x100001f4 0x00020 0x00020 R   0x4
   ABIFLAGS       0x000218 0x10000218 0x10000218 0x00018 0x00018 R   0x8
   REGINFO        0x000230 0x10000230 0x10000230 0x00018 0x00018 R   0x8
-  LOAD           0x000000 0x10000000 0x10000000 0xd9194 0xd9194 R E 0x10000
-  LOAD           0x0d95e0 0x100e95e0 0x100e95e0 0x03a48 0x0d530 RW  0x10000
   DYNAMIC        0x000248 0x10000248 0x10000248 0x00108 0x00108 R   0x4
-  NOTE           0x0001f4 0x100001f4 0x100001f4 0x00020 0x00020 R   0x4
-  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RWE 0x10
+  LOAD           0x0d95e0 0x100e95e0 0x100e95e0 0x03a48 0x0d530 RW  0x10000
   GNU_RELRO      0x0d95e0 0x100e95e0 0x100e95e0 0x00a20 0x00a20 R   0x1
-  NULL           0x000000 0x00000000 0x00000000 0x00000 0x00000     0x4

  Section to Segment mapping:
   Segment Sections...
    00
-   01     .interp
-   02     .MIPS.abiflags
-   03     .reginfo
-   04     .interp .note.ABI-tag .MIPS.abiflags .reginfo .dynamic .hash .dynsym .dynstr .gnu.version .gnu.version_r .init .text .MIPS.stubs .fini .rodata .eh_frame
-   05     .ctors .dtors .data.rel.ro .data .rld_map .got .sdata .sbss .bss
-   06     .dynamic
-   07     .note.ABI-tag
-   08
-   09     .ctors .dtors .data.rel.ro
-   10
+   01
+   02
+   03     .interp .note.ABI-tag .MIPS.abiflags .reginfo .dynamic .hash .dynsym .dynstr .gnu.version .gnu.version_r .init .text .MIPS.stubs .fini .rodata .eh_frame
+   04     .interp
+   05     .note.ABI-tag
+   06     .MIPS.abiflags
+   07     .reginfo
+   08     .dynamic
+   09     .ctors .dtors .data.rel.ro .data .rld_map .got .sdata .sbss .bss
+   10     .ctors .dtors .data.rel.ro

 Dynamic section at offset 0x248 contains 28 entries:
   Tag        Type                         Name/Value
@@ -102,7 +102,7 @@
  0x0000000a (STRSZ)                      26578 (bytes)
  0x0000000b (SYMENT)                     16 (bytes)
  0x70000016 (MIPS_RLD_MAP)               0x100eb840
- 0x70000035 (MIPS_RLD_MAP_REL)           0xeb598
+ 0x70000035 (MIPS_RLD_MAP_REL)           0xeb658
  0x00000015 (DEBUG)                      0x0
  0x00000003 (PLTGOT)                     0x100eb850
  0x70000001 (MIPS_RLD_VERSION)           1

Unfortunately the result is corrupt:

$ /////////////////////////////////////////////////////////////////////////////tmp/q/lib/ld.so.1 ./bash+
Segmentation fault

even though the original works correctly:

$ /////////////////////////////////////////////////////////////////////////////tmp/q/lib/ld.so.1 ./bash
\[\]I have no name!@brant:/tmp/q/bin$ exit

[ghost]

Would it be possible to make a 0.14.4 release at or after a992616? Then I can submit a PR to update nixpkgs. I've started working on upstreaming my nixpkgs-on-mips64 stuff.

[Mic92]

df7c57a

[ghost]

awesome, thanks!