CVE-2024-44971

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

net: dsa: bcm_sf2: Fix a possible memory leak in bcm_sf2_mdio_register()

bcm_sf2_mdio_register() calls of_phy_find_device() and then phy_device_remove() in a loop to remove existing PHY devices. of_phy_find_device() eventually calls bus_find_device(), which calls get_device() on the returned struct device * to increment the refcount. The current implementation does not decrement the refcount, which causes memory leak.

This commit adds the missing phy_device_free() call to decrement the refcount via put_device() to balance the refcount.

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/7feef10768ea71d468d9bbc1e0d14c461876768c
• https://git.kernel.org/stable/c/a7d2808d67570e6acae45c2a96e0d59986888e4c
• https://git.kernel.org/stable/c/b7b8d9f5e679af60c94251fd6728dde34be69a71
• https://git.kernel.org/stable/c/c05516c072903f6fb9134b8e7e1ad4bffcdc4819
• https://git.kernel.org/stable/c/e3862093ee93fcfbdadcb7957f5f8974fffa806a
• https://git.kernel.org/stable/c/f3d5efe18a11f94150fee8b3fda9d62079af640a
• https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html
• https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html