CVE-2022-49277

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

jffs2: fix memory leak in jffs2_do_mount_fs

If jffs2_build_filesystem() in jffs2_do_mount_fs() returns an error, we can observe the following kmemleak report:

unreferenced object 0xffff88811b25a640 (size 64): comm mount, pid 691, jiffies 4294957728 (age 71.952s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ……………. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ……………. backtrace: [] kmem_cache_alloc_trace+0x584/0x880 [] jffs2_sum_init+0x86/0x130 [] jffs2_do_mount_fs+0x798/0xac0 [] jffs2_do_fill_super+0x383/0xc30 [] jffs2_fill_super+0x2ea/0x4c0 […] unreferenced object 0xffff88812c760000 (size 65536): comm mount, pid 691, jiffies 4294957728 (age 71.952s) hex dump (first 32 bytes): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ……………. bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ……………. backtrace: [] __kmalloc+0x6b9/0x910 [] jffs2_sum_init+0xd7/0x130 [] jffs2_do_mount_fs+0x798/0xac0 [] jffs2_do_fill_super+0x383/0xc30 [] jffs2_fill_super+0x2ea/0x4c0 […]

This is because the resources allocated in jffs2_sum_init() are not released. Call jffs2_sum_exit() to release these resources to solve the problem.

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/0978e9af4559a171ac7a74a1b3ef21804b0a0fa9
• https://git.kernel.org/stable/c/2a9d8184458562e6bf2f40d0e677fc85e2dd3834
• https://git.kernel.org/stable/c/4392e8aeebc5a4f8073620bccba7de1b1f6d7c88
• https://git.kernel.org/stable/c/5f34310d1376ca5b2ed798258def2c2ab3cc6699
• https://git.kernel.org/stable/c/607d3aab7349f18e0d9dba4100d09d16fe27caca
• https://git.kernel.org/stable/c/9a0f6610c7daedd2eace430beeb08a8b7ac80699
• https://git.kernel.org/stable/c/c94128470e6fe53d9bd9d16d2d3271813f9d37af
• https://git.kernel.org/stable/c/d051cef784de4d54835f6b6836d98a8f6935772c
• https://git.kernel.org/stable/c/dbe0d0521eaa6a3d235517319266c539bb5c5112