CVE-2022-49959

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

openvswitch: fix memory leak at failed datapath creation

ovs_dp_cmd_new()->ovs_dp_change()->ovs_dp_set_upcall_portids() allocates array via kmalloc. If for some reason new_vport() fails during ovs_dp_cmd_new() dp->upcall_portids must be freed. Add missing kfree.

Kmemleak example: unreferenced object 0xffff88800c382500 (size 64): comm dump_state, pid 323, jiffies 4294955418 (age 104.347s) hex dump (first 32 bytes): 5e c2 79 e4 1f 7a 38 c7 09 21 38 0c 80 88 ff ff ^.y..z8..!8….. 03 00 00 00 0a 00 00 00 14 00 00 00 28 00 00 00 …………(… backtrace: [<0000000071bebc9f>] ovs_dp_set_upcall_portids+0x38/0xa0 [<000000000187d8bd>] ovs_dp_change+0x63/0xe0 [<000000002397e446>] ovs_dp_cmd_new+0x1f0/0x380 [<00000000aa06f36e>] genl_family_rcv_msg_doit+0xea/0x150 [<000000008f583bc4>] genl_rcv_msg+0xdc/0x1e0 [<00000000fa10e377>] netlink_rcv_skb+0x50/0x100 [<000000004959cece>] genl_rcv+0x24/0x40 [<000000004699ac7f>] netlink_unicast+0x23e/0x360 [<00000000c153573e>] netlink_sendmsg+0x24e/0x4b0 [<000000006f4aa380>] sock_sendmsg+0x62/0x70 [<00000000d0068654>] ____sys_sendmsg+0x230/0x270 [<0000000012dacf7d>] ___sys_sendmsg+0x88/0xd0 [<0000000011776020>] __sys_sendmsg+0x59/0xa0 [<000000002e8f2dc1>] do_syscall_64+0x3b/0x90 [<000000003243e7cb>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

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/a87406f4adee9c53b311d8a1ba2849c69e29a6d0
• https://git.kernel.org/stable/c/c0c1c0241917459644326a1a3102207c871ae159
• https://git.kernel.org/stable/c/ca54b2bfaab385778e55a9fd33f6c31e7f743b48