Linux Kernel up to 5.15.4 RDMA use after free

Summaryinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 5.15.4. The affected element is an unknown function of the component RDMA. Executing a manipulation can lead to use after free. This vulnerability is tracked as CVE-2021-47196. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.15.4. It has been declared as problematic. This vulnerability affects some unknown functionality of the component RDMA. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Set send and receive CQ before forwarding to the driver Preset both receive and send CQ pointers prior to call to the drivers and overwrite it later again till the mlx4 is going to be changed do not overwrite ibqp properties. This change is needed for mlx5, because in case of QP creation failure, it will go to the path of QP destroy which relies on proper CQ pointers. BUG: KASAN: use-after-free in create_qp.cold+0x164/0x16e [mlx5_ib] Write of size 8 at addr ffff8880064c55c0 by task a.out/246 CPU: 0 PID: 246 Comm: a.out Not tainted 5.15.0+ #291 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack_lvl+0x45/0x59 print_address_description.constprop.0+0x1f/0x140 kasan_report.cold+0x83/0xdf create_qp.cold+0x164/0x16e [mlx5_ib] mlx5_ib_create_qp+0x358/0x28a0 [mlx5_ib] create_qp.part.0+0x45b/0x6a0 [ib_core] ib_create_qp_user+0x97/0x150 [ib_core] ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs] ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs] ib_uverbs_ioctl+0x169/0x260 [ib_uverbs] __x64_sys_ioctl+0x866/0x14d0 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Allocated by task 246: kasan_save_stack+0x1b/0x40 __kasan_kmalloc+0xa4/0xd0 create_qp.part.0+0x92/0x6a0 [ib_core] ib_create_qp_user+0x97/0x150 [ib_core] ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs] ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs] ib_uverbs_ioctl+0x169/0x260 [ib_uverbs] __x64_sys_ioctl+0x866/0x14d0 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 246: kasan_save_stack+0x1b/0x40 kasan_set_track+0x1c/0x30 kasan_set_free_info+0x20/0x30 __kasan_slab_free+0x10c/0x150 slab_free_freelist_hook+0xb4/0x1b0 kfree+0xe7/0x2a0 create_qp.part.0+0x52b/0x6a0 [ib_core] ib_create_qp_user+0x97/0x150 [ib_core] ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs] ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs] ib_uverbs_ioctl+0x169/0x260 [ib_uverbs] __x64_sys_ioctl+0x866/0x14d0 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2021-47196 since 03/25/2024. The exploitation appears to be difficult. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/10/2024).

Upgrading to version 5.15.5 or 5.16 eliminates this vulnerability. Applying the patch b70e072feffa/6cd7397d01c4 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion