Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com
☎ 03 60 47 09 81 - info@securiteinfo.com
In the Linux kernel, the following vulnerability has been resolved:bpf: Fix helper writes to read-only mapsLonial found an issue that despite user- and BPF-side frozen BPF map(like in case of .rodata), it was still possible to write into it froma BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT}as arguments.In check_func_arg() when the argument is as mentioned, the meta->raw_modeis never set. Later, check_helper_mem_access(), under the case ofPTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for thesubsequent call to check_map_access_type() and given the BPF map isread-only it succeeds.The helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINITwhen results are written into them as opposed to read out of them. Thelatter indicates that it's okay to pass a pointer to uninitialized memoryas the memory is written to anyway.However, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEMjust with additional alignment requirement. So it is better to just getrid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse thefixed size memory types. For this, add MEM_ALIGNED to additionally ensurealignment given these helpers write directly into the args via *
No PoCs from references.
- https://github.com/fkie-cad/nvd-json-data-feeds
- https://github.com/terawhiz/exploits
- https://github.com/w4zu/Debian_security