CVE-2024-56741

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

apparmor: test: Fix memory leak for aa_unpack_strdup()

The string allocated by kmemdup() in aa_unpack_strdup() is not freed and cause following memory leaks, free them to fix it.

unreferenced object 0xffffff80c6af8a50 (size 8):
  comm kunit_try_catch, pid 225, jiffies 4294894407
  hex dump (first 8 bytes):
    74 65 73 74 69 6e 67 00                          testing.
  backtrace (crc 5eab668b):
    [<0000000001e3714d>] kmemleak_alloc+0x34/0x40
    [<000000006e6c7776>] __kmalloc_node_track_caller_noprof+0x300/0x3e0
    [<000000006870467c>] kmemdup_noprof+0x34/0x60
    [<000000001176bb03>] aa_unpack_strdup+0xd0/0x18c
    [<000000008ecde918>] policy_unpack_test_unpack_strdup_with_null_name+0xf8/0x3ec
    [<0000000032ef8f77>] kunit_try_run_case+0x13c/0x3ac
    [<00000000f3edea23>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<00000000adf936cf>] kthread+0x2e8/0x374
    [<0000000041bb1628>] ret_from_fork+0x10/0x20
unreferenced object 0xffffff80c2a29090 (size 8):
  comm kunit_try_catch, pid 227, jiffies 4294894409
  hex dump (first 8 bytes):
    74 65 73 74 69 6e 67 00                          testing.
  backtrace (crc 5eab668b):
    [<0000000001e3714d>] kmemleak_alloc+0x34/0x40
    [<000000006e6c7776>] __kmalloc_node_track_caller_noprof+0x300/0x3e0
    [<000000006870467c>] kmemdup_noprof+0x34/0x60
    [<000000001176bb03>] aa_unpack_strdup+0xd0/0x18c
    [<0000000046a45c1a>] policy_unpack_test_unpack_strdup_with_name+0xd0/0x3c4
    [<0000000032ef8f77>] kunit_try_run_case+0x13c/0x3ac
    [<00000000f3edea23>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<00000000adf936cf>] kthread+0x2e8/0x374
    [<0000000041bb1628>] ret_from_fork+0x10/0x20

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/2a9b68f2dc6812bd1b8880b5c00e60203d6f61f6
• https://git.kernel.org/stable/c/5354599855a9b5568e05ce686119ee3ff8b19bd5
• https://git.kernel.org/stable/c/59a149e7c38e7b76616c8b333fc6aa5b6fb2293c
• https://git.kernel.org/stable/c/7290f59231910ccba427d441a6e8b8c6f6112448
• https://git.kernel.org/stable/c/89265f88701e54dde255ddf862093baeca57548c
• https://git.kernel.org/stable/c/d62ee5739a66644b0e7f11e657d562458cdcdea3
• https://git.kernel.org/stable/c/f856246ff6da25c4f8fdd73a9c875e878b085e9f