CVE-2022-50532

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

scsi: mpt3sas: Fix possible resource leaks in mpt3sas_transport_port_add()

In mpt3sas_transport_port_add(), if sas_rphy_add() returns error, sas_rphy_free() needs be called to free the resource allocated in sas_end_device_alloc(). Otherwise a kernel crash will happen:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000108 CPU: 45 PID: 37020 Comm: bash Kdump: loaded Tainted: G W 6.1.0-rc1+ #189 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=–) pc : device_del+0x54/0x3d0 lr : device_del+0x37c/0x3d0 Call trace: device_del+0x54/0x3d0 attribute_container_class_device_del+0x28/0x38 transport_remove_classdev+0x6c/0x80 attribute_container_device_trigger+0x108/0x110 transport_remove_device+0x28/0x38 sas_rphy_remove+0x50/0x78 [scsi_transport_sas] sas_port_delete+0x30/0x148 [scsi_transport_sas] do_sas_phy_delete+0x78/0x80 [scsi_transport_sas] device_for_each_child+0x68/0xb0 sas_remove_children+0x30/0x50 [scsi_transport_sas] sas_rphy_remove+0x38/0x78 [scsi_transport_sas] sas_port_delete+0x30/0x148 [scsi_transport_sas] do_sas_phy_delete+0x78/0x80 [scsi_transport_sas] device_for_each_child+0x68/0xb0 sas_remove_children+0x30/0x50 [scsi_transport_sas] sas_remove_host+0x20/0x38 [scsi_transport_sas] scsih_remove+0xd8/0x420 [mpt3sas]

Because transport_add_device() is not called when sas_rphy_add() fails, the device is not added. When sas_rphy_remove() is subsequently called to remove the device in the remove() path, a NULL pointer dereference happens.

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/6a92129c8f999ff5b122c100ce7f625eb3e98c4b
• https://git.kernel.org/stable/c/6f6768e2fc8638fabdd8802c2ef693d7aef01db1
• https://git.kernel.org/stable/c/78316e9dfc24906dd474630928ed1d3c562b568e
• https://git.kernel.org/stable/c/ce1a69cc85006b494353911b35171da195d79e25
• https://git.kernel.org/stable/c/d17bca3ddfe507874cb826d32721552da12e741f
• https://git.kernel.org/stable/c/d60000cb1195a464080b0efb4949daf7594e0020