Bug 2348128 (CVE-2022-49513)

Summary: CVE-2022-49513 kernel: cpufreq: governor: Use kobject release() method to free dbs_data
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A vulnerability was found in the Linux kernel's cpufreq subsystem. The `dbs_data` struct, which embeds a `kobject`, improperly attempts to free the struct using `kfree()` rather than through the proper `release()` method. This issue can lead to a use-after-free scenario, resulting in system instability, memory corruption, or potential arbitrary code execution.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2025-02-26 03:18:36 UTC 
In the Linux kernel, the following vulnerability has been resolved:

cpufreq: governor: Use kobject release() method to free dbs_data

The struct dbs_data embeds a struct gov_attr_set and
the struct gov_attr_set embeds a kobject. Since every kobject must have
a release() method and we can't use kfree() to free it directly,
so introduce cpufreq_dbs_data_release() to release the dbs_data via
the kobject::release() method. This fixes the calltrace like below:

  ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x34
  WARNING: CPU: 12 PID: 810 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
  Modules linked in:
  CPU: 12 PID: 810 Comm: sh Not tainted 5.16.0-next-20220120-yocto-standard+ #536
  Hardware name: Marvell OcteonTX CN96XX board (DT)
  pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  pc : debug_print_object+0xb8/0x100
  lr : debug_print_object+0xb8/0x100
  sp : ffff80001dfcf9a0
  x29: ffff80001dfcf9a0 x28: 0000000000000001 x27: ffff0001464f0000
  x26: 0000000000000000 x25: ffff8000090e3f00 x24: ffff80000af60210
  x23: ffff8000094dfb78 x22: ffff8000090e3f00 x21: ffff0001080b7118
  x20: ffff80000aeb2430 x19: ffff800009e8f5e0 x18: 0000000000000000
  x17: 0000000000000002 x16: 00004d62e58be040 x15: 013590470523aff8
  x14: ffff8000090e1828 x13: 0000000001359047 x12: 00000000f5257d14
  x11: 0000000000040591 x10: 0000000066c1ffea x9 : ffff8000080d15e0
  x8 : ffff80000a1765a8 x7 : 0000000000000000 x6 : 0000000000000001
  x5 : ffff800009e8c000 x4 : ffff800009e8c760 x3 : 0000000000000000
  x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0001474ed040
  Call trace:
   debug_print_object+0xb8/0x100
   __debug_check_no_obj_freed+0x1d0/0x25c
   debug_check_no_obj_freed+0x24/0xa0
   kfree+0x11c/0x440
   cpufreq_dbs_governor_exit+0xa8/0xac
   cpufreq_exit_governor+0x44/0x90
   cpufreq_set_policy+0x29c/0x570
   store_scaling_governor+0x110/0x154
   store+0xb0/0xe0
   sysfs_kf_write+0x58/0x84
   kernfs_fop_write_iter+0x12c/0x1c0
   new_sync_write+0xf0/0x18c
   vfs_write+0x1cc/0x220
   ksys_write+0x74/0x100
   __arm64_sys_write+0x28/0x3c
   invoke_syscall.constprop.0+0x58/0xf0
   do_el0_svc+0x70/0x170
   el0_svc+0x54/0x190
   el0t_64_sync_handler+0xa4/0x130
   el0t_64_sync+0x1a0/0x1a4
  irq event stamp: 189006
  hardirqs last  enabled at (189005): [<ffff8000080849d0>] finish_task_switch.isra.0+0xe0/0x2c0
  hardirqs last disabled at (189006): [<ffff8000090667a4>] el1_dbg+0x24/0xa0
  softirqs last  enabled at (188966): [<ffff8000080106d0>] __do_softirq+0x4b0/0x6a0
  softirqs last disabled at (188957): [<ffff80000804a618>] __irq_exit_rcu+0x108/0x1a4

[ rjw: Because can be freed by the gov_attr_set_put() in
  cpufreq_dbs_governor_exit() now, it is also necessary to put the
  invocation of the governor ->exit() callback into the new
  cpufreq_dbs_data_release() function. ]
Comment 1 Avinash Hanwate 2025-02-26 22:13:54 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022609-CVE-2022-49513-f147@gregkh/T