CVE-2023-52560

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

mm/damon/vaddr-test: fix memory leak in damon_do_test_apply_three_regions()

When CONFIG_DAMON_VADDR_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y and CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.

Since commit 9f86d624292c (mm/damon/vaddr-test: remove unnecessary variables), the damon_destroy_ctx() is removed, but still call damon_new_target() and damon_new_region(), the damon_region which is allocated by kmem_cache_alloc() in damon_new_region() and the damon_target which is allocated by kmalloc in damon_new_target() are not freed. And the damon_region which is allocated in damon_new_region() in damon_set_regions() is also not freed.

So use damon_destroy_target to free all the damon_regions and damon_target.

unreferenced object 0xffff888107c9a940 (size 64):
  comm kunit_try_catch, pid 1069, jiffies 4294670592 (age 732.761s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b  ............kkkk
    60 c7 9c 07 81 88 ff ff f8 cb 9c 07 81 88 ff ff  `...............
  backtrace:
    [<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
    [<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
    [<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
    [<ffffffff819c82be>] damon_test_apply_three_regions1+0x21e/0x260
    [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
    [<ffffffff81237cf6>] kthread+0x2b6/0x380
    [<ffffffff81097add>] ret_from_fork+0x2d/0x70
    [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff8881079cc740 (size 56):
  comm kunit_try_catch, pid 1069, jiffies 4294670592 (age 732.761s)
  hex dump (first 32 bytes):
    05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00  ................
    6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b  kkkkkkkk....kkkk
  backtrace:
    [<ffffffff819bc492>] damon_new_region+0x22/0x1c0
    [<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
    [<ffffffff819c82be>] damon_test_apply_three_regions1+0x21e/0x260
    [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
    [<ffffffff81237cf6>] kthread+0x2b6/0x380
    [<ffffffff81097add>] ret_from_fork+0x2d/0x70
    [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff888107c9ac40 (size 64):
  comm kunit_try_catch, pid 1071, jiffies 4294670595 (age 732.843s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b  ............kkkk
    a0 cc 9c 07 81 88 ff ff 78 a1 76 07 81 88 ff ff  ........x.v.....
  backtrace:
    [<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
    [<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
    [<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
    [<ffffffff819c851e>] damon_test_apply_three_regions2+0x21e/0x260
    [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
    [<ffffffff81237cf6>] kthread+0x2b6/0x380
    [<ffffffff81097add>] ret_from_fork+0x2d/0x70
    [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff8881079ccc80 (size 56):
  comm kunit_try_catch, pid 1071, jiffies 4294670595 (age 732.843s)
  hex dump (first 32 bytes):
    05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00  ................
    6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b  kkkkkkkk....kkkk
  backtrace:
    [<ffffffff819bc492>] damon_new_region+0x22/0x1c0
    [<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
    [<ffffffff819c851e>] damon_test_apply_three_regions2+0x21e/0x260
    [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
    [<ffffffff81237cf6>] kthread+0x2b6/0x380
    [<ffffffff81097add>] ret_from_fork+0x2d/0x70
    [<ffff

—truncated—

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/45120b15743fa7c0aa53d5db6dfb4c8f87be4abd
• https://git.kernel.org/stable/c/6b522001693aa113d97a985abc5f6932972e8e86
• https://git.kernel.org/stable/c/9a4fe81a8644b717d57d81ce5849e16583b13fe8
• https://git.kernel.org/stable/c/45120b15743fa7c0aa53d5db6dfb4c8f87be4abd
• https://git.kernel.org/stable/c/6b522001693aa113d97a985abc5f6932972e8e86
• https://git.kernel.org/stable/c/9a4fe81a8644b717d57d81ce5849e16583b13fe8