Unable to Cross compile seccom-pledge for OpenWrt

[mrdorababu]

Hi,

We are unable to cross-compile the project for OpenWrt. Please let us know what are the architectures it can support. The OpenWrt router we have has MIPS architecture.

• CPU info for OpenWrt router

root@OpenWrt:~# cat /proc/cpuinfo                                                               
system type             : MediaTek MT7621 ver:1 eco:3                                           
machine                 : Linksys E5600                                                         
processor               : 0                                                                     
cpu model               : MIPS 1004Kc V2.15                                                     
BogoMIPS                : 586.13                                                                
wait instruction        : yes                                                                   
microsecond timers      : yes                                                                   
tlb_entries             : 32                                                                    
extra interrupt vector  : yes                                                                   
hardware watchpoint     : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]     
isa                     : mips1 mips2 mips32r1 mips32r2                                         
ASEs implemented        : mips16 dsp mt                                                         
Options implemented     : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal
 vint perf_cntr_intr_bit cdmm perf                                                              
shadow register sets    : 1                                                                     
kscratch registers      : 0                                                                     
package                 : 0                                                                     
core                    : 0                                                                     
VPE                     : 0                                                                     
VCED exceptions         : not available                                                         
VCEI exceptions         : not available                                                         
                                                                                                
processor               : 1                                                                     
cpu model               : MIPS 1004Kc V2.15                                                     
BogoMIPS                : 586.13                                                                
wait instruction        : yes                                                                   
microsecond timers      : yes                                                                   
tlb_entries             : 32                                                                    
extra interrupt vector  : yes                                                                   
hardware watchpoint     : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]     
isa                     : mips1 mips2 mips32r1 mips32r2                                         
ASEs implemented        : mips16 dsp mt                                                         
Options implemented     : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal
 vint perf_cntr_intr_bit cdmm perf                                                              
shadow register sets    : 1                                                                     
kscratch registers      : 0                                                                     
package                 : 0                                                                     
core                    : 0                                                                     
VPE                     : 1                                                                     
VCED exceptions         : not available                                                         
VCEI exceptions         : not available                                                         
                                                                                                
processor               : 2                                                                     
cpu model               : MIPS 1004Kc V2.15                                                     
BogoMIPS                : 586.13                                                                
wait instruction        : yes                                                                   
microsecond timers      : yes                                                                   
tlb_entries             : 32                                                                    
extra interrupt vector  : yes                                                                   
hardware watchpoint     : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]     
isa                     : mips1 mips2 mips32r1 mips32r2                                         
ASEs implemented        : mips16 dsp mt                                                         
Options implemented     : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal
 vint perf_cntr_intr_bit cdmm perf                                                              
shadow register sets    : 1                                                                     
kscratch registers      : 0                                                                     
package                 : 0                                                                     
core                    : 1                                                                     
VPE                     : 0                                                                     
VCED exceptions         : not available                                                         
VCEI exceptions         : not available                                                         
                                                                                                
processor               : 3                                                                     
cpu model               : MIPS 1004Kc V2.15                                                     
BogoMIPS                : 586.13                                                                
wait instruction        : yes                                                                   
microsecond timers      : yes                                                                   
tlb_entries             : 32                                                                    
extra interrupt vector  : yes                                                                   
hardware watchpoint     : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]     
isa                     : mips1 mips2 mips32r1 mips32r2                                         
ASEs implemented        : mips16 dsp mt                                                         
Options implemented     : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal
 vint perf_cntr_intr_bit cdmm perf                                                              
shadow register sets    : 1                                                                     
kscratch registers      : 0                                                                     
package                 : 0                                                                     
core                    : 1                                                                     
VPE                     : 1                                                                     
VCED exceptions         : not available                                                         
VCEI exceptions         : not available

• Following errors occurred while we build the project

dora@openwrtbuildpc:~/coderepo/openwrt/seccomp-pledge$ cargo build --release --target mips-unknown-linux-musl
   Compiling serde v1.0.152
   Compiling libc v0.2.139
   Compiling serde_json v1.0.91
   Compiling itoa v1.0.5
   Compiling ryu v1.0.12
   Compiling optional-fields-serde-macro v0.1.1
   Compiling optional-field v0.1.3
   Compiling seccompiler v0.3.0
   Compiling seccomp-pledge v0.1.0 (/home/dora/coderepo/openwrt/seccomp-pledge)
error[E0432]: unresolved import `seccompiler::BpfMap`
 --> src/main.rs:2:5
  |
2 | use seccompiler::BpfMap;
  |     ^^^^^^^^^^^^^^^^^^^ no `BpfMap` in the root

error[E0433]: failed to resolve: could not find `TargetArch` in `seccompiler`
   --> src/main.rs:411:22
    |
411 |         seccompiler::TargetArch::x86_64,
    |                      ^^^^^^^^^^ could not find `TargetArch` in `seccompiler`

error[E0425]: cannot find function `compile_from_json` in crate `seccompiler`
   --> src/main.rs:409:66
    |
409 | ...compiler::compile_from_json(
    |              ^^^^^^^^^^^^^^^^^ not found in `seccompiler`

error[E0425]: cannot find function `apply_filter` in crate `seccompiler`
   --> src/main.rs:428:21
    |
428 |     if seccompiler::apply_filter(filter).is_err() {
    |                     ^^^^^^^^^^^^ not found in `seccompiler`

Some errors have detailed explanations: E0425, E0432, E0433.
For more information about an error, try `rustc --explain E0425`.
error: could not compile `seccomp-pledge` due to 4 previous errors
dora@openwrtbuildpc:~/coderepo/openwrt/seccomp-pledge$

You can find the further details here
https://www.notion.so/subcom/Daily-Logs-ef770c7e27f7457f875a198c65a5f604

Please let us know how to solve these errors.

[DeviousCilantro]

This project utilizes the seccompiler crate which unfortunately only supports little-endian x86_64 and little-endian aarch64 host architectures, as specified in https://github.com/rust-vmm/seccompiler. Moreover, Justine Tunney's standalone pledge binary itself is an x86_64 ELF executable, so I am not sure even that would work on MIPS either.

[sn99]

@DeviousCilantro It builds natively without cross compiling. Nvm, english ggs

I think the issue is in the linker during cross compiling, seccompiler doesn’t define a linker target for mips https://github.com/rust-vmm/seccompiler/blob/main/.cargo/config, I found this that can help though rust-lang/rust#37507 (comment)

[sn99]

This library is only supported for x86_64 and aarch64.