{"uuid": "c51dffd9-f5fb-4218-98b8-feace6bcdc65", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2024-49861", "type": "seen", "source": "https://t.me/cvedetector/8487", "content": "{\n  \"Source\": \"CVE FEED\",\n  \"Title\": \"CVE-2024-49861 - Linux Kernel BPF Off-Path Write Weakness Cisco\", \n  \"Content\": \"CVE ID : CVE-2024-49861 \nPublished : Oct. 21, 2024, 1:15 p.m. | 41\u00a0minutes ago \nDescription : In the Linux kernel, the following vulnerability has been resolved:  \n  \nbpf: Fix helper writes to read-only maps  \n  \nLonial found an issue that despite user- and BPF-side frozen BPF map  \n(like in case of .rodata), it was still possible to write into it from  \na BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT}  \nas arguments.  \n  \nIn check_func_arg() when the argument is as mentioned, the meta->raw_mode  \nis never set. Later, check_helper_mem_access(), under the case of  \nPTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for the  \nsubsequent call to check_map_access_type() and given the BPF map is  \nread-only it succeeds.  \n  \nThe helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINIT  \nwhen results are written into them as opposed to read out of them. The  \nlatter indicates that it's okay to pass a pointer to uninitialized memory  \nas the memory is written to anyway.  \n  \nHowever, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEM  \njust with additional alignment requirement. So it is better to just get  \nrid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse the  \nfixed size memory types. For this, add MEM_ALIGNED to additionally ensure  \nalignment given these helpers write directly into the args via * = val.  \nThe .arg*_size has been initialized reflecting the actual sizeof(*).  \n  \nMEM_ALIGNED can only be used in combination with MEM_FIXED_SIZE annotated  \nargument types, since in !MEM_FIXED_SIZE cases the verifier does not know  \nthe buffer size a priori and therefore cannot blindly write * = val. \nSeverity: 0.0 | NA \nVisit the link for more details, such as CVSS details, affected products, timeline, and more...\",\n  \"Detection Date\": \"21 Oct 2024\",\n  \"Type\": \"Vulnerability\"\n}\n\ud83d\udd39 t.me/cvedetector \ud83d\udd39", "creation_timestamp": "2024-10-21T16:00:56.000000Z"}