ghsa-qrrc-56f8-gw3j
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
bpf: Prevent tailcall infinite loop caused by freplace
There is a potential infinite loop issue that can occur when using a combination of tail calls and freplace.
In an upcoming selftest, the attach target for entry_freplace of tailcall_freplace.c is subprog_tc of tc_bpf2bpf.c, while the tail call in entry_freplace leads to entry_tc. This results in an infinite loop:
entry_tc -> subprog_tc -> entry_freplace --tailcall-> entry_tc.
The problem arises because the tail_call_cnt in entry_freplace resets to zero each time entry_freplace is executed, causing the tail call mechanism to never terminate, eventually leading to a kernel panic.
To fix this issue, the solution is twofold:
- Prevent updating a program extended by an freplace program to a prog_array map.
- Prevent extending a program that is already part of a prog_array map with an freplace program.
This ensures that:
- If a program or its subprogram has been extended by an freplace program, it can no longer be updated to a prog_array map.
- If a program has been added to a prog_array map, neither it nor its subprograms can be extended by an freplace program.
Moreover, an extension program should not be tailcalled. As such, return -EINVAL if the program has a type of BPF_PROG_TYPE_EXT when adding it to a prog_array map.
Additionally, fix a minor code style issue by replacing eight spaces with a tab for proper formatting.
{ "affected": [], "aliases": [ "CVE-2024-47794" ], "database_specific": { "cwe_ids": [], "github_reviewed": false, "github_reviewed_at": null, "nvd_published_at": "2025-01-11T13:15:22Z", "severity": null }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Prevent tailcall infinite loop caused by freplace\n\nThere is a potential infinite loop issue that can occur when using a\ncombination of tail calls and freplace.\n\nIn an upcoming selftest, the attach target for entry_freplace of\ntailcall_freplace.c is subprog_tc of tc_bpf2bpf.c, while the tail call in\nentry_freplace leads to entry_tc. This results in an infinite loop:\n\nentry_tc -\u003e subprog_tc -\u003e entry_freplace --tailcall-\u003e entry_tc.\n\nThe problem arises because the tail_call_cnt in entry_freplace resets to\nzero each time entry_freplace is executed, causing the tail call mechanism\nto never terminate, eventually leading to a kernel panic.\n\nTo fix this issue, the solution is twofold:\n\n1. Prevent updating a program extended by an freplace program to a\n prog_array map.\n2. Prevent extending a program that is already part of a prog_array map\n with an freplace program.\n\nThis ensures that:\n\n* If a program or its subprogram has been extended by an freplace program,\n it can no longer be updated to a prog_array map.\n* If a program has been added to a prog_array map, neither it nor its\n subprograms can be extended by an freplace program.\n\nMoreover, an extension program should not be tailcalled. As such, return\n-EINVAL if the program has a type of BPF_PROG_TYPE_EXT when adding it to a\nprog_array map.\n\nAdditionally, fix a minor code style issue by replacing eight spaces with a\ntab for proper formatting.", "id": "GHSA-qrrc-56f8-gw3j", "modified": "2025-01-11T15:30:28Z", "published": "2025-01-11T15:30:28Z", "references": [ { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-47794" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/987aa730bad3e1ef66d9f30182294daa78f6387d" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/d6083f040d5d8f8d748462c77e90547097df936e" } ], "schema_version": "1.4.0", "severity": [] }
Sightings
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