CVE-2024-38539

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

RDMA/cma: Fix kmemleak in rdma_core observed during blktests nvme/rdma use siw

When running blktests nvme/rdma, the following kmemleak issue will appear.

kmemleak: Kernel memory leak detector initialized (mempool available:36041) kmemleak: Automatic memory scanning thread started kmemleak: 2 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 8 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 17 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 4 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

unreferenced object 0xffff88855da53400 (size 192): comm rdma, pid 10630, jiffies 4296575922 hex dump (first 32 bytes): 37 00 00 00 00 00 00 00 c0 ff ff ff 1f 00 00 00 7…………… 10 34 a5 5d 85 88 ff ff 10 34 a5 5d 85 88 ff ff .4.]…..4.]…. backtrace (crc 47f66721): [] kmalloc_trace+0x30d/0x3b0 [] alloc_gid_entry+0x47/0x380 [ib_core] [] add_modify_gid+0x166/0x930 [ib_core] [] ib_cache_update.part.0+0x6d8/0x910 [ib_core] [] ib_cache_setup_one+0x24a/0x350 [ib_core] [] ib_register_device+0x9e/0x3a0 [ib_core] [] 0xffffffffc2a3d389 [] nldev_newlink+0x2b8/0x520 [ib_core] [] rdma_nl_rcv_msg+0x2c3/0x520 [ib_core] [] rdma_nl_rcv_skb.constprop.0.isra.0+0x23c/0x3a0 [ib_core] [] netlink_unicast+0x445/0x710 [] netlink_sendmsg+0x761/0xc40 [] __sys_sendto+0x3a9/0x420 [] __x64_sys_sendto+0xdc/0x1b0 [] do_syscall_64+0x93/0x180 [] entry_SYSCALL_64_after_hwframe+0x71/0x79

The root cause: rdma_put_gid_attr is not called when sgid_attr is set to ERR_PTR(-ENODEV).

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/3eb127dc408bf7959a4920d04d16ce10e863686a
• https://git.kernel.org/stable/c/6564fc1818404254d1c9f7d75b403b4941516d26
• https://git.kernel.org/stable/c/9c0731832d3b7420cbadba6a7f334363bc8dfb15
• https://git.kernel.org/stable/c/b3a7fb93afd888793ef226e9665fbda98a95c48e