1.6 KiB
CVE-2024-41042
Description
In the Linux kernel, the following vulnerability has been resolved:netfilter: nf_tables: prefer nft_chain_validatenft_chain_validate already performs loop detection because a cycle willresult in a call stack overflow (ctx->level >= NFT_JUMP_STACK_SIZE).It also follows maps via ->validate callback in nft_lookup, so thereappears no reason to iterate the maps again.nf_tables_check_loops() and all its helper functions can be removed.This improves ruleset load time significantly, from 23s down to 12s.This also fixes a crash bug. Old loop detection code can result inunbounded recursion:BUG: TASK stack guard page was hit at ....Oops: stack guard page: 0000 [#1] PREEMPT SMP KASANCPU: 4 PID: 1539 Comm: nft Not tainted 6.10.0-rc5+ #1[..]with a suitable ruleset during validation of register stores.I can't see any actual reason to attempt to check for this fromnft_validate_register_store(), at this point the transaction is still inprogress, so we don't have a full picture of the rule graph.For nf-next it might make sense to either remove it or make this dependon table->validate_state in case we could catch an error earlier(for improved error reporting to userspace).
POC
Reference
No PoCs from references.