CVE-2022-48691

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_tables: clean up hook list when offload flags check fails

splice back the hook list so nft_chain_release_hook() has a chance to release the hooks.

BUG: memory leak unreferenced object 0xffff88810180b100 (size 96): comm syz-executor133, pid 3619, jiffies 4294945714 (age 12.690s) hex dump (first 32 bytes): 28 64 23 02 81 88 ff ff 28 64 23 02 81 88 ff ff (d#…..(d#….. 90 a8 aa 83 ff ff ff ff 00 00 b5 0f 81 88 ff ff ……………. backtrace: [] kmalloc include/linux/slab.h:600 [inline] [] nft_netdev_hook_alloc+0x3b/0xc0 net/netfilter/nf_tables_api.c:1901 [] nft_chain_parse_netdev net/netfilter/nf_tables_api.c:1998 [inline] [] nft_chain_parse_hook+0x33a/0x530 net/netfilter/nf_tables_api.c:2073 [] nf_tables_addchain.constprop.0+0x10b/0x950 net/netfilter/nf_tables_api.c:2218 [] nf_tables_newchain+0xa8b/0xc60 net/netfilter/nf_tables_api.c:2593 [] nfnetlink_rcv_batch+0xa46/0xd20 net/netfilter/nfnetlink.c:517 [] nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:638 [inline] [] nfnetlink_rcv+0x1f9/0x220 net/netfilter/nfnetlink.c:656 [] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] [] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345 [] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921 [] sock_sendmsg_nosec net/socket.c:714 [inline] [] sock_sendmsg+0x56/0x80 net/socket.c:734 [] ____sys_sendmsg+0x36c/0x390 net/socket.c:2482 [] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536 [] __sys_sendmsg+0x88/0x100 net/socket.c:2565 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Weakness

The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/1ce55ec5cb7c573c983dffbe290b8d17caf1f157
• https://git.kernel.org/stable/c/77972a36ecc4db7fc7c68f0e80714263c5f03f65
• https://git.kernel.org/stable/c/910891a2a44cdc49efcc4fe7459c1085ba00d0f4
• https://git.kernel.org/stable/c/94ed8eeb8d9aeb00e4f4e19b83a2e28b6442fbc5