UBUNTU-CVE-2024-50212
In the Linux kernel, the following vulnerability has been resolved: lib: alloc_tag_module_unload must wait for pending kfree_rcu calls Ben Greear reports following splat: ------------[ cut here ]------------ net/netfilter/nf_nat_core.c:1114 module nf_nat func:nf_nat_register_fn has 256 allocated at module unload WARNING: CPU: 1 PID: 10421 at lib/alloc_tag.c:168 alloc_tag_module_unload+0x22b/0x3f0 Modules linked in: nf_nat(-) btrfs ufs qnx4 hfsplus hfs minix vfat msdos fat ... Hardware name: Default string Default string/SKYBAY, BIOS 5.12 08/04/2020 RIP: 0010:alloc_tag_module_unload+0x22b/0x3f0 codetag_unload_module+0x19b/0x2a0 ? codetag_load_module+0x80/0x80 nf_nat module exit calls kfree_rcu on those addresses, but the free operation is likely still pending by the time alloc_tag checks for leaks. Wait for outstanding kfree_rcu operations to complete before checking resolves this warning. Reproducer: unshare -n iptables-nft -t nat -A PREROUTING -p tcp grep nf_nat /proc/allocinfo # will list 4 allocations rmmod nft_chain_nat rmmod nf_nat # will WARN. [[email protected]: add comment]
02 / AFFECTED SOFTWARE
Affected packages
16 explicit affected versions
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16 explicit affected versions
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3 explicit affected versions
16 explicit affected versions
43 explicit affected versions
11 explicit affected versions
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35 explicit affected versions
12 explicit affected versions
13 explicit affected versions
6 explicit affected versions
12 explicit affected versions
12 explicit affected versions
27 explicit affected versions
12 explicit affected versions
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: lib: alloc_tag_module_unload must wait for pending kfree_rcu calls Ben Greear reports following splat: ------------[ cut here ]------------ net/netfilter/nf_nat_core.c:1114 module nf_nat func:nf_nat_register_fn has 256 allocated at module unload WARNING: CPU: 1 PID: 10421 at lib/alloc_tag.c:168 alloc_tag_module_unload+0x22b/0x3f0 Modules linked in: nf_nat(-) btrfs ufs qnx4 hfsplus hfs minix vfat msdos fat ... Hardware name: Default string Default string/SKYBAY, BIOS 5.12 08/04/2020 RIP: 0010:alloc_tag_module_unload+0x22b/0x3f0 codetag_unload_module+0x19b/0x2a0 ? codetag_load_module+0x80/0x80 nf_nat module exit calls kfree_rcu on those addresses, but the free operation is likely still pending by the time alloc_tag checks for leaks. Wait for outstanding kfree_rcu operations to complete before checking resolves this warning. Reproducer: unshare -n iptables-nft -t nat -A PREROUTING -p tcp grep nf_nat /proc/allocinfo # will list 4 allocations rmmod nft_chain_nat rmmod nf_nat # will WARN. [[email protected]: add comment]
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/dc783ba4b9df3fb3e76e968b2cbeb9960069263c
- https://git.kernel.org/stable/c/24211fb49c9ac1b576470b7e393a5a0b50af2707
- https://git.kernel.org/stable/c/dc783ba4b9df3fb3e76e968b2cbeb9960069263c
- https://ubuntu.com/security/CVE-2024-50212
- https://ubuntu.com/security/notices/USN-7276-1
- https://ubuntu.com/security/notices/USN-7277-1
- https://ubuntu.com/security/notices/USN-7310-1
- https://www.cve.org/CVERecord?id=CVE-2024-50212