cbcvebase.
CVE-2022-48853
published 2024-07-16

CVE-2022-48853: In the Linux kernel, the following vulnerability has been resolved: swiotlb: fix info leak with DMA_FROM_DEVICE The problem I'm addressing was discovered by…

PriorityP426medium5.5CVSS 3.1
AVLACLPRLUINSUCHINAN
EPSS
0.27%
18.3th percentile
In the Linux kernel, the following vulnerability has been resolved: swiotlb: fix info leak with DMA_FROM_DEVICE The problem I'm addressing was discovered by the LTP test covering cve-2018-1000204. A short description of what happens follows: 1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV and a corresponding dxferp. The peculiar thing about this is that TUR is not reading from the device. 2) In sg_start_req() the invocation of blk_rq_map_user() effectively bounces the user-space buffer. As if the device was to transfer into it. Since commit a45b599ad808 ("scsi: sg: allocate with __GFP_ZERO in sg_build_indirect()") we make sure this first bounce buffer is allocated with GFP_ZERO. 3) For the rest of the story we keep ignoring that we have a TUR, so the device won't touch the buffer we prepare as if the we had a DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device and the buffer allocated by SG is mapped by the function virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here scatter-gather and not scsi generics). This mapping involves bouncing via the swiotlb (we need swiotlb to do virtio in protected guest like s390 Secure Execution, or AMD SEV). 4) When the SCSI TUR is done, we first copy back the content of the second (that is swiotlb) bounce buffer (which most likely contains some previous IO data), to the first bounce buffer, which contains all zeros. Then we copy back the content of the first bounce buffer to the user-space buffer. 5) The test case detects that the buffer, which it zero-initialized, ain't all zeros and fails. One can argue that this is an swiotlb problem, because without swiotlb we leak all zeros, and the swiotlb should be transparent in a sense that it does not affect the outcome (if all other participants are well behaved). Copying the content of the original buffer into the swiotlb buffer is the only way I can th

Affected

22 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.16.18-1 (bookworm)linux 5.16.18-1 (bookworm)
linuxlinux——
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < fd97de9c7b973f46a6103f4170c5efc7b8ef8797fd97de9c7b973f46a6103f4170c5efc7b8ef8797
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < aaf166f37eb6bb55d81c3e40a2a460c8875c8813aaf166f37eb6bb55d81c3e40a2a460c8875c8813
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 06cb238b0f7ac1669cb06390704c61794724c19106cb238b0f7ac1669cb06390704c61794724c191
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b2f140a9f980806f572d672e1780acea66b9a25cb2f140a9f980806f572d672e1780acea66b9a25c
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f3f2247ac31cb71d1f05f56536df5946c6652f4af3f2247ac31cb71d1f05f56536df5946c6652f4a
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7007c894631cf43041dcfa0da7142bbaa7eb673c7007c894631cf43041dcfa0da7142bbaa7eb673c
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < dcead36b19d999d687cd9c99b7f37520d9102b57dcead36b19d999d687cd9c99b7f37520d9102b57
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f2141881b530738777c28bb51c62175895c8178bf2141881b530738777c28bb51c62175895c8178b
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544
linuxlinux_kernel< 4.9.3204.9.320
linuxlinux_kernel>= 0 < 5.10.113-15.10.113-1
linuxlinux_kernel>= 0 < 5.16.18-15.16.18-1
linuxlinux_kernel>= 0 < 5.16.18-15.16.18-1
linuxlinux_kernel>= 0 < 5.16.18-15.16.18-1
linuxlinux_kernel>= 4.10 < 4.14.2814.14.281
linuxlinux_kernel>= 4.15 < 4.19.2454.19.245
linuxlinux_kernel>= 4.20 < 5.4.1895.4.189
linuxlinux_kernel>= 5.11 < 5.15.295.15.29
linuxlinux_kernel>= 5.16 < 5.16.155.16.15
linuxlinux_kernel>= 5.5 < 5.10.1105.10.110

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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