CVE-2022-49073
What it is
In the Linux kernel, the following vulnerability has been resolved: ata: sata_dwc_460ex: Fix crash due to OOB write the driver uses libata's "tag" values from in various arrays. Since the mentioned patch bumped the ATA_TAG_INTERNAL to 32, the value of the SATA_DWC_QCMD_MAX needs to account for that. Otherwise ATA_TAG_INTERNAL usage cause similar crashes like this as reported by Tice Rex on the OpenWrt Forum and reproduced (with symbols) here: | BUG: Kernel NULL pointer dereference at 0x00000000 | Faulting instruction address: 0xc03ed4b8 | Oops: Kernel access of bad area, sig: 11 [#1] | BE PAGE_SIZE=4K PowerPC 44x Platform | CPU: 0 PID: 362 Comm: scsi_eh_1 Not tainted 5.4.163 #0 | NIP: c03ed4b8 LR: c03d27e8 CTR: c03ed36c | REGS: cfa59950 TRAP: 0300 Not tainted (5.4.163) | MSR: 00021000 <CE,ME> CR: 42000222 XER: 00000000 | DEAR: 00000000 ESR: 00000000 | GPR00: c03d27e8 cfa59a08 cfa55fe0 00000000 0fa46bc0 [...] | [..] | NIP [c03ed4b8] sata_dwc_qc_issue+0x14c/0x254 | LR [c03d27e8] ata_qc_issue+0x1c8/0x2dc | Call Trace: | [cfa59a08] [c003f4e0] __cancel_work_timer+0x124/0x194 (unreliable) | [cfa59a78] [c03d27e8] ata_qc_issue+0x1c8/0x2dc | [cfa59a98] [c03d2b3c] ata_exec_internal_sg+0x240/0x524 | [cfa59b08] [c03d2e98] ata_exec_internal+0x78/0xe0 | [cfa59b58] [c03d30fc] ata_read_log_page.part.38+0x1dc/0x204 | [cfa59bc8] [c03d324c] ata_identify_page_supported+0x68/0x130 | [...] This is because sata_dwc_dma_xfer_complete() NULLs the dma_pending's next neighbour "chan" (a *dma_chan struct) in this '32' case right here (line ~735): > hsdevp->dma_pending[tag] = SATA_DWC_DMA_PENDING_NONE; Then the next time, a dma gets issued; dma_dwc_xfer_setup() passes the NULL'd hsdevp->chan to the dmaengine_slave_config() which then causes the crash. With this patch, SATA_DWC_QCMD_MAX is now set to ATA_MAX_QUEUE + 1. This avoids the OOB. But please note, there was a worthwhile discussion on what ATA_TAG_INTERNAL and ATA_MAX_QUEUE is. And why there should not be a "fake" 33 command-long queue size. Ideally, the dw driver should account for the ATA_TAG_INTERNAL. In Damien Le Moal's words: "... having looked at the driver, it is a bigger change than just faking a 33rd "tag" that is in fact not a command tag at all." BugLink: https://github.com/openwrt/openwrt/issues/9505
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.3% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Details
- Published
- Last modified
- Exploit probability
- 0.3% · EPSS, next 30 days
- Weakness
- CWE-787 · Out-of-bounds write
- Record status
- Modified
Affected
- Linux Kernel < 4.19.238
- Linux Kernel < 5.4.189
- Linux Kernel < 5.10.111
- Linux Kernel < 5.15.34
- Linux Kernel < 5.16.20
- Linux Kernel < 5.17.3
- Linux Kernel 5.18
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Fix and advisories
- https://git.kernel.org/stable/c/234c0132f76f0676d175757f61b0025191a3d935
- https://git.kernel.org/stable/c/3a8751c0d4e24129e72dcec0139e99833b13904a
- https://git.kernel.org/stable/c/55e1465ba79562a191708a40eeae3f8082a209e3
- https://git.kernel.org/stable/c/596c7efd69aae94f4b0e91172b075eb197958b99
- https://git.kernel.org/stable/c/7aa8104a554713b685db729e66511b93d989dd6a
- https://git.kernel.org/stable/c/8a05a6952ecd59aaa62cbdcdaf523ae2c8f436e8
- https://git.kernel.org/stable/c/fc629224aa62f23849cae83717932985ac51232d
References
- https://git.kernel.org/stable/c/234c0132f76f0676d175757f61b0025191a3d935
- https://git.kernel.org/stable/c/3a8751c0d4e24129e72dcec0139e99833b13904a
- https://git.kernel.org/stable/c/55e1465ba79562a191708a40eeae3f8082a209e3
- https://git.kernel.org/stable/c/596c7efd69aae94f4b0e91172b075eb197958b99
- https://git.kernel.org/stable/c/7aa8104a554713b685db729e66511b93d989dd6a
- https://git.kernel.org/stable/c/8a05a6952ecd59aaa62cbdcdaf523ae2c8f436e8
- https://git.kernel.org/stable/c/fc629224aa62f23849cae83717932985ac51232d