Linux Kernel up to 5.10.37/5.11.21/5.12.4 ucsi rdo_index position array index

Summaryinfo

A vulnerability classified as problematic has been found in Linux Kernel up to 5.10.37/5.11.21/5.12.4. The impacted element is the function rdo_index of the component ucsi. Performing a manipulation of the argument position results in array index. This vulnerability is cataloged as CVE-2021-46980. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 5.10.37/5.11.21/5.12.4 (Operating System). This affects the function rdo_index of the component ucsi. The manipulation of the argument position with an unknown input leads to a array index vulnerability. CWE is classifying the issue as CWE-129. The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4 commit 4dbc6a4ef06d ("usb: typec: ucsi: save power data objects in PD mode") introduced retrieval of the PDOs when connected to a PD-capable source. But only the first 4 PDOs are received since that is the maximum number that can be fetched at a time given the MESSAGE_IN length limitation (16 bytes). However, as per the PD spec a connected source may advertise up to a maximum of 7 PDOs. If such a source is connected it's possible the PPM could have negotiated a power contract with one of the PDOs at index greater than 4, and would be reflected in the request data object's (RDO) object position field. This would result in an out-of-bounds access when the rdo_index() is used to index into the src_pdos array in ucsi_psy_get_voltage_now(). With the help of the UBSAN -fsanitize=array-bounds checker enabled this exact issue is revealed when connecting to a PD source adapter that advertise 5 PDOs and the PPM enters a contract having selected the 5th one. [ 151.545106][ T70] Unexpected kernel BRK exception at EL1 [ 151.545112][ T70] Internal error: BRK handler: f2005512 [#1] PREEMPT SMP ... [ 151.545499][ T70] pc : ucsi_psy_get_prop+0x208/0x20c [ 151.545507][ T70] lr : power_supply_show_property+0xc0/0x328 ... [ 151.545542][ T70] Call trace: [ 151.545544][ T70] ucsi_psy_get_prop+0x208/0x20c [ 151.545546][ T70] power_supply_uevent+0x1a4/0x2f0 [ 151.545550][ T70] dev_uevent+0x200/0x384 [ 151.545555][ T70] kobject_uevent_env+0x1d4/0x7e8 [ 151.545557][ T70] power_supply_changed_work+0x174/0x31c [ 151.545562][ T70] process_one_work+0x244/0x6f0 [ 151.545564][ T70] worker_thread+0x3e0/0xa64 We can resolve this by instead retrieving and storing up to the maximum of 7 PDOs in the con->src_pdos array. This would involve two calls to the GET_PDOS command.

The weakness was shared 02/28/2024. The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2021-46980 since 02/27/2024. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/31/2024).

Upgrading to version 5.10.38, 5.11.22, 5.12.5 or 5.13 eliminates this vulnerability. Applying the patch e5366bea0277/a453bfd7ef15/5e9c6f58b01e/1f4642b72be7 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.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.0
• 5.10.1
• 5.10.2
• 5.10.3
• 5.10.4
• 5.10.5
• 5.10.6
• 5.10.7
• 5.10.8
• 5.10.9
• 5.10.10
• 5.10.11
• 5.10.12
• 5.10.13
• 5.10.14
• 5.10.15
• 5.10.16
• 5.10.17
• 5.10.18
• 5.10.19
• 5.10.20
• 5.10.21
• 5.10.22
• 5.10.23
• 5.10.24
• 5.10.25
• 5.10.26
• 5.10.27
• 5.10.28
• 5.10.29
• 5.10.30
• 5.10.31
• 5.10.32
• 5.10.33
• 5.10.34
• 5.10.35
• 5.10.36
• 5.10.37
• 5.11.0
• 5.11.1
• 5.11.2
• 5.11.3
• 5.11.4
• 5.11.5
• 5.11.6
• 5.11.7
• 5.11.8
• 5.11.9
• 5.11.10
• 5.11.11
• 5.11.12
• 5.11.13
• 5.11.14
• 5.11.15
• 5.11.16
• 5.11.17
• 5.11.18
• 5.11.19
• 5.11.20
• 5.11.21
• 5.12.0
• 5.12.1
• 5.12.2
• 5.12.3
• 5.12.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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