Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: fib6: fix NULL deref in fib6_walk_continue() on multi-batch dump inet6_dump_fib() saves its progress in cb->args[1] as a positional index within the current hash chain. Between batches, a concurrent fib6_new_table() can insert a new table at the chain head, shifting all existing entries. The saved index then lands on a different table, causing fib6_dump_table() to set w->root to the wrong table while w->node still points into the previous one. fib6_walk_continue() dereferences w->node->parent (NULL) and panics: BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:fib6_walk_continue+0x6e/0x170 Call Trace: <TASK> fib6_dump_table.isra.0+0xc5/0x240 inet6_dump_fib+0xf6/0x420 rtnl_dumpit+0x30/0xa0 netlink_dump+0x15b/0x460 netlink_recvmsg+0x1d6/0x2a0 ____sys_recvmsg+0x17a/0x190 Fix by storing tb->tb6_id in cb->args[1] instead of a positional index. On resume, skip entries until the id matches; a concurrent head-insert can never match the saved id, so the walker always resumes on the correct table.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < ee73a32dd258d4af66831ff006b771e19812b322affected1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < 89f9c5fee3c64c5cabc34e65599308fd3c879cf9affected1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < cb90a774a9c6c46961a44949a246fbb61f5f934caffected1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < 27210d433a8c5fe6bf7278a04bbaeb49a81d0290affected1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < 059efb48dd746518898faaa9b965511009b59639affected1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < d8a01d27873e04bebd357dc87859aa756e0b28b2affected1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < 110ccbd28c9444866fcc84ba96a2ad64fa6e95aeaffected1b43af5480c351dbcb2eef478bafe179cbeb6e83 to < 9facb861dc6b9b9ea9793ef5032a9a826f7a4229affected
Linux Linux
Default version status: affected
2.6.19affected0 to < 2.6.19unaffected5.10.265 to ≤ 5.10.*unaffected5.15.212 to ≤ 5.15.*unaffected6.1.183 to ≤ 6.1.*unaffected6.6.151 to ≤ 6.6.*unaffected6.12.97 to ≤ 6.12.*unaffected6.18.40 to ≤ 6.18.*unaffected7.1.5 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/ee73a32dd258d4af66831ff006b771e19812b322 ↗
- https://git.kernel.org/stable/c/89f9c5fee3c64c5cabc34e65599308fd3c879cf9 ↗
- https://git.kernel.org/stable/c/cb90a774a9c6c46961a44949a246fbb61f5f934c ↗
- https://git.kernel.org/stable/c/27210d433a8c5fe6bf7278a04bbaeb49a81d0290 ↗
- https://git.kernel.org/stable/c/059efb48dd746518898faaa9b965511009b59639 ↗
- https://git.kernel.org/stable/c/d8a01d27873e04bebd357dc87859aa756e0b28b2 ↗
- https://git.kernel.org/stable/c/110ccbd28c9444866fcc84ba96a2ad64fa6e95ae ↗
- https://git.kernel.org/stable/c/9facb861dc6b9b9ea9793ef5032a9a826f7a4229 ↗