llvm-strip fail on cgo code with error: SHT_STRTAB string table section [index 4] is non-null terminated

[kraj]

Attached example is causing strip failures

$ mips-yoe-linux-llvm-strip --remove-section=.note --remove-section=.comment go-helloworld
$ mips-yoe-linux-llvm-strip --remove-section=.note --remove-section=.comment go-helloworld
./recipe-sysroot-native/usr/bin/mips-yoe-linux/mips-yoe-linux-llvm-strip: error: SHT_STRTAB string table section [index 4] is non-null terminated

you have to run the strip twice to get this error. However when I use GNU strip first time then it works fine during second time.
so it seems llvm-strip is mutilating the binary during first strip operation somehow.
go-helloworld.tar.gz

[llvmbot]

@llvm/issue-subscribers-tools-llvm-objcopy-strip

[llvmbot]

@llvm/issue-subscribers-backend-mips

[berolinux]

This is platform independent and seems to happen with anything built by go.

$ cat test.go
package main
import "fmt"
func main() {
        fmt.Println("hello world")
}
$ go build test.go
$ llvm-strip test
$ llvm-strip test
llvm-strip: error: SHT_STRTAB string table section [index 3] is non-null terminated

readelf -a after the first llvm-strip shows section names getting corrupted (first 3 bytes chopped off). Probably the size of a remaining section is miscalculated, causing the first bytes of the succeeding section to end up in the old section.

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] .text             PROGBITS         0000000000401000  00001000
       000000000007cfe7  0000000000000000  AX       0     0     32
  [ 2] typelink          PROGBITS         000000000047e000  0007e000
       00000000000350c4  0000000000000000   A       0     0     32
  [ 3] ldinfo            STRTAB           0000000000000000  000b30e0
       0000000000000081  0000000000000000           0     0     1
  [ 4] ss                PROGBITS         00000000004b3260  000b3260
       00000000000004c0  0000000000000000   A       0     0     32
  [ 5] zzer_extra_c[...] PROGBITS         00000000004b3720  000b3720
       0000000000000058  0000000000000000   A       0     0     32
  [ 6] id                PROGBITS         00000000004b3778  000b3778
       0000000000000000  0000000000000000   A       0     0     1
  [ 7] te.go.buildid     PROGBITS         00000000004b3780  000b3780
       0000000000053878  0000000000000000   A       0     0     32
  [ 8] a                 PROGBITS         0000000000507000  00107000
       0000000000000110  0000000000000000  WA       0     0     16
  [ 9] a                 PROGBITS         0000000000507120  00107120
       00000000000105e0  0000000000000000  WA       0     0     32
  [10]                   PROGBITS         0000000000517700  00117700
       00000000000077d0  0000000000000000  WA       0     0     32
  [11]                   NOBITS           000000000051eee0  0011eee0
       000000000002ef60  0000000000000000  WA       0     0     32
  [12] .noptrdata        NOBITS           000000000054de40  0014de40
       0000000000005188  0000000000000000  WA       0     0     32
  [13] _counters         NOTE             0000000000400f9c  00000f9c
       0000000000000064  0000000000000000   A       0     0     4

[berolinux]

Also happens with an even smaller test case:

package main
func main() {
        return
}

[agherzan]

For reference these are the section headers on the unstripped binary:

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] .text             PROGBITS         0000000000401000  00001000
       0000000000054210  0000000000000000  AX       0     0     32
  [ 2] .rodata           PROGBITS         0000000000456000  00056000
       00000000000225b7  0000000000000000   A       0     0     32
  [ 3] .shstrtab         STRTAB           0000000000000000  000785c0
       000000000000017a  0000000000000000           0     0     1
  [ 4] .typelink         PROGBITS         0000000000478740  00078740
       00000000000002b0  0000000000000000   A       0     0     32
  [ 5] .itablink         PROGBITS         00000000004789f0  000789f0
       0000000000000008  0000000000000000   A       0     0     8
  [ 6] .gosymtab         PROGBITS         00000000004789f8  000789f8
       0000000000000000  0000000000000000   A       0     0     1
  [ 7] .gopclntab        PROGBITS         0000000000478a00  00078a00
       000000000003b988  0000000000000000   A       0     0     32
  [ 8] .go.buildinfo     PROGBITS         00000000004b5000  000b5000
       0000000000000110  0000000000000000  WA       0     0     16
  [ 9] .noptrdata        PROGBITS         00000000004b5120  000b5120
       00000000000011a0  0000000000000000  WA       0     0     32
  [10] .data             PROGBITS         00000000004b62c0  000b62c0
       00000000000021f0  0000000000000000  WA       0     0     32
  [11] .bss              NOBITS           00000000004b84c0  000b84c0
       000000000002eb60  0000000000000000  WA       0     0     32
  [12] .noptrbss         NOBITS           00000000004e7020  000e7020
       0000000000005148  0000000000000000  WA       0     0     32
  [13] .zdebug_abbrev    PROGBITS         00000000004ed000  000b9000
       0000000000000127  0000000000000000           0     0     1
  [14] .zdebug_line      PROGBITS         00000000004ed127  000b9127
       000000000001365d  0000000000000000           0     0     1
  [15] .zdebug_frame     PROGBITS         0000000000500784  000cc784
       0000000000003c35  0000000000000000           0     0     1
  [16] .debug_gdb_s[...] PROGBITS         00000000005043b9  000d03b9
       0000000000000028  0000000000000000           0     0     1
  [17] .zdebug_info      PROGBITS         00000000005043e1  000d03e1
       0000000000022a50  0000000000000000           0     0     1
  [18] .zdebug_loc       PROGBITS         0000000000526e31  000f2e31
       0000000000012202  0000000000000000           0     0     1
  [19] .zdebug_ranges    PROGBITS         0000000000539033  00105033
       0000000000006611  0000000000000000           0     0     1
  [20] .note.go.buildid  NOTE             0000000000400f9c  00000f9c
       0000000000000064  0000000000000000   A       0     0     4
  [21] .symtab           SYMTAB           0000000000000000  0010b648
       00000000000078f0  0000000000000018          22    84     8
  [22] .strtab           STRTAB           0000000000000000  00112f38
       0000000000006edf  0000000000000000

Also, this doesn't seem to always reproduce on go projects:

• https://github.com/containernetworking/cni.git (build it in cnitool) - fails when stripping twice or more
• https://github.com/opencontainers/runc.git - never fails when stripping

^ Same go, same llvm, etc.

[agherzan]

After digging a bit more into this, it looks like the moving part is cgo.

package main

/*
void foo(void) {}
*/
import "C"

func main() {
    return
}

This would work as expected while commenting out the import would reproduce this issue.

[emaste]

Issue also observed in FreeBSD's attempt to use LLVM binutils for the entire ports tree: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=270962