CVE-2024-50084

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

net: microchip: vcap api: Fix memory leaks in vcap_api_encode_rule_test()

Commit a3c1e45156ad (net: microchip: vcap: Fix use-after-free error in kunit test) fixed the use-after-free error, but introduced below memory leaks by removing necessary vcap_free_rule(), add it to fix it.

unreferenced object 0xffffff80ca58b700 (size 192):
  comm kunit_try_catch, pid 1215, jiffies 4294898264
  hex dump (first 32 bytes):
    00 12 7a 00 05 00 00 00 0a 00 00 00 64 00 00 00  ..z.........d...
    00 00 00 00 00 00 00 00 00 04 0b cc 80 ff ff ff  ................
  backtrace (crc 9c09c3fe):
    [<0000000052a0be73>] kmemleak_alloc+0x34/0x40
    [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4
    [<0000000040a01b8d>] vcap_alloc_rule+0x3cc/0x9c4
    [<000000003fe86110>] vcap_api_encode_rule_test+0x1ac/0x16b0
    [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac
    [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<00000000c5d82c9a>] kthread+0x2e8/0x374
    [<00000000f4287308>] ret_from_fork+0x10/0x20
unreferenced object 0xffffff80cc0b0400 (size 64):
  comm kunit_try_catch, pid 1215, jiffies 4294898265
  hex dump (first 32 bytes):
    80 04 0b cc 80 ff ff ff 18 b7 58 ca 80 ff ff ff  ..........X.....
    39 00 00 00 02 00 00 00 06 05 04 03 02 01 ff ff  9...............
  backtrace (crc daf014e9):
    [<0000000052a0be73>] kmemleak_alloc+0x34/0x40
    [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4
    [<000000000ff63fd4>] vcap_rule_add_key+0x2cc/0x528
    [<00000000dfdb1e81>] vcap_api_encode_rule_test+0x224/0x16b0
    [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac
    [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<00000000c5d82c9a>] kthread+0x2e8/0x374
    [<00000000f4287308>] ret_from_fork+0x10/0x20
unreferenced object 0xffffff80cc0b0700 (size 64):
  comm kunit_try_catch, pid 1215, jiffies 4294898265
  hex dump (first 32 bytes):
    80 07 0b cc 80 ff ff ff 28 b7 58 ca 80 ff ff ff  ........(.X.....
    3c 00 00 00 00 00 00 00 01 2f 03 b3 ec ff ff ff  <......../......
  backtrace (crc 8d877792):
    [<0000000052a0be73>] kmemleak_alloc+0x34/0x40
    [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4
    [<000000006eadfab7>] vcap_rule_add_action+0x2d0/0x52c
    [<00000000323475d1>] vcap_api_encode_rule_test+0x4d4/0x16b0
    [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac
    [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<00000000c5d82c9a>] kthread+0x2e8/0x374
    [<00000000f4287308>] ret_from_fork+0x10/0x20
unreferenced object 0xffffff80cc0b0900 (size 64):
  comm kunit_try_catch, pid 1215, jiffies 4294898266
  hex dump (first 32 bytes):
    80 09 0b cc 80 ff ff ff 80 06 0b cc 80 ff ff ff  ................
    7d 00 00 00 01 00 00 00 00 00 00 00 ff 00 00 00  }...............
  backtrace (crc 34181e56):
    [<0000000052a0be73>] kmemleak_alloc+0x34/0x40
    [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4
    [<000000000ff63fd4>] vcap_rule_add_key+0x2cc/0x528
    [<00000000991e3564>] vcap_val_rule+0xcf0/0x13e8
    [<00000000fc9868e5>] vcap_api_encode_rule_test+0x678/0x16b0
    [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac
    [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<00000000c5d82c9a>] kthread+0x2e8/0x374
    [<00000000f4287308>] ret_from_fork+0x10/0x20
unreferenced object 0xffffff80cc0b0980 (size 64):
  comm kunit_try_catch, pid 1215, jiffies 4294898266
  hex dump (first 32 bytes):
    18 b7 58 ca 80 ff ff ff 00 09 0b cc 80 ff ff ff  ..X.............
    67 00 00 00 00 00 00 00 01 01 74 88 c0 ff ff ff  g.........t.....
  backtrace (crc 275fd9be):
    [<0000000052a0be73>] kmemleak_alloc+0x34/0x40
    [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4
    [<000000000ff63fd4>] vcap_rule_add_key+0x2cc/0x528
    [<000000001396a1a2>] test_add_de

—truncated—

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/170792097bb21e5da77443b6a03d35489813eabe
• https://git.kernel.org/stable/c/20b5342de51bda794791e013b90754774003a515
• https://git.kernel.org/stable/c/217a3d98d1e9891a8b1438a27dfbc64ddf01f691