Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: igmp: convert struct ip_sf_list to RCU Commit 23d2b94043ca ("igmp: Add ip_mc_list lock in ip_check_mc_rcu") added spin_lock_bh(&im->lock) to ip_check_mc_rcu() to prevent a use-after-free while iterating im->sources during concurrent deletions. However, ip_check_mc_rcu() is called from RCU read-side critical sections in packet receive and route lookup fast paths (e.g. __mkroute_output(), ip_route_input_rcu(), and __udp4_lib_rcv()). When igmpv3_send_cr() or igmpv3_send_report() holds &pmc->lock and calls add_grec() -> igmpv3_newpack() -> ip_route_output_ports(), an XFRM policy matching a multicast destination triggers xfrm_tmpl_resolve_one() -> xfrm4_get_saddr() -> __mkroute_output() -> ip_check_mc_rcu(). This attempts to acquire &im->lock while &pmc->lock is already held on the same CPU, triggering a lockdep recursive locking warning / deadlock. Fix this by converting IPv4 struct ip_sf_list to RCU, mirroring the IPv6 implementation in net/ipv6/mcast.c: 1. Add struct rcu_head to struct ip_sf_list and annotate sf_next, sources, and tomb as __rcu pointers. 2. Use rcu_assign_pointer() and kfree_rcu() for list updates and deletions. 3. Remove spin_lock_bh(&im->lock) from ip_check_mc_rcu() and traverse im->sources locklessly with for_each_psf_rcu(), reading and writing counter fields with READ_ONCE() and WRITE_ONCE(). Note: RCU conversion of /proc/net/mcfilter will be done in a separate patch.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 23d2b94043ca8835bd1e67749020e839f396a1c2 before 01131daffc4b64f1652e23dc3e6e2f601eda781d; affected 23d2b94043ca8835bd1e67749020e839f396a1c2 before f5182dfad54277267a8cb0c004a9cd4cf35aeebb; affected 23d2b94043ca8835bd1e67749020e839f396a1c2 before d3011d1f293478c730aa0870490afa145c37600e; affected 23d2b94043ca8835bd1e67749020e839f396a1c2 before e3206419bdb04e2087d8cc6be324df8639b3fac5; affected 23d2b94043ca8835bd1e67749020e839f396a1c2 before 2987ee196c88dbde0463dc87d5fb209c684e34a2; affected b24065948ae6c48c9e20891f8cfe9850f1d748be; affected e9924c4204ede999b0515fd31a370a1e27f676bc; affected 78967749984cf3614de346c90f3e259ff8272735; affected 4768973dffed4d0126854514335ed4fe87bec1ab; affected d84708451d9041dff8a81e3718f821f12d2eb6c5; affected ddd7e8b7b84836c584a284b98ca9bd7a348a0558; affected 961447ff60291b91e27d5c32fa549c1411ad3b70; affected d1a3c6d5925a8d00a32c5ef2d674dd9c0ce89c95; affected 4.4.284 before 4.5; affected 4.9.283 before 4.10; affected 4.14.247 before 4.15; affected 4.19.207 before 4.20; affected 5.4.145 before 5.5; affected 5.10.64 before 5.11; affected 5.13.16 before 5.14; affected 5.14.3 before 5.15 |
| Linux / Linux | affected 5.15; unaffected 0 before 5.15; unaffected 6.6.160 through 6.6.*; unaffected 6.12.111 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/01131daffc4b64f1652e23dc3e6e2f601eda781d
- https://git.kernel.org/stable/c/f5182dfad54277267a8cb0c004a9cd4cf35aeebb
- https://git.kernel.org/stable/c/d3011d1f293478c730aa0870490afa145c37600e
- https://git.kernel.org/stable/c/e3206419bdb04e2087d8cc6be324df8639b3fac5
- https://git.kernel.org/stable/c/2987ee196c88dbde0463dc87d5fb209c684e34a2