Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ip6mr: do not clone dst in ip6mr_cache_report() IPv6 input attaches a non-refcounted (NOREF) dst to skbs under RCU. When an ingress multicast packet misses MFC lookup, ip6mr_cache_unresolved() places the skb onto the unresolved queue, escaping the receive-side RCU grace period. If the underlying route is deleted and freed, and the MFC queue is later resolved with a wrong parent interface, ip6_mr_forward() invokes ip6mr_cache_report(..., MRT6MSG_WRONGMIF), which executes dst_clone(skb_dst(pkt)) on the freed dst entry, triggering a slab use-after-free. Report packets queued to mroute6_sk (a raw socket) and netlink notifications do not require an attached dst entry. Fix this by: 1. Removing dst_clone() in ip6mr_cache_report() and ensuring report skbs do not hold a dst. 2. Dropping skb_dst before queuing unresolved skbs in ip6mr_cache_unresolved(), matching the fact that multicast forwarding resolves outgoing routes anew via ip6_route_output().
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 67f415dd29063a5906c560051c00e42dcf01a4dd before 7f8287f606c8c028d4224e85d95dc448c6d6d623; affected 67f415dd29063a5906c560051c00e42dcf01a4dd before 42ef371466d5648f5c9e8bc219f0af0a2c2bbf8c; affected 67f415dd29063a5906c560051c00e42dcf01a4dd before f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89; affected 67f415dd29063a5906c560051c00e42dcf01a4dd before 4a674afaae4136c71943aa3e35d433676fd40e8f; affected 67f415dd29063a5906c560051c00e42dcf01a4dd before 235b42b5860189eb8c27c36435ad932cae65a734 |
| Linux / Linux | affected 5.3; unaffected 0 before 5.3; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.57 through 6.18.*; unaffected 7.2.6 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/7f8287f606c8c028d4224e85d95dc448c6d6d623
- https://git.kernel.org/stable/c/42ef371466d5648f5c9e8bc219f0af0a2c2bbf8c
- https://git.kernel.org/stable/c/f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89
- https://git.kernel.org/stable/c/4a674afaae4136c71943aa3e35d433676fd40e8f
- https://git.kernel.org/stable/c/235b42b5860189eb8c27c36435ad932cae65a734