In the Linux kernel, the following vulnerability has been resolved:
cxl/region: Fix null pointer dereference for resetting decoder
Not all decoders have a reset callback.
The CXL specification allows a host bridge with a single root port to
have no explicit HDM decoders. Currently the region driver assumes there
are none. As such the CXL core creates a special pass through decoder
instance without a commit/reset callback.
Prior to this patch, the ->reset() callback was called unconditionally when
calling cxl_region_decode_reset. Thus a configuration with 1 Host Bridge,
1 Root Port, and one directly attached CXL type 3 device or multiple CXL
type 3 devices attached to downstream ports of a switch can cause a null
pointer dereference.
Before the fix, a kernel crash was observed when we destroy the region, and
a pass through decoder is reset.
The issue can be reproduced as below,
1) create a region with a CXL setup which includes a HB with a
single root port under which a memdev is attached directly.
2) destroy the region with cxl destroy-region regionX -f.
Vendor | Product | Version | CPE |
---|---|---|---|
linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/cxl/core/region.c"
],
"versions": [
{
"version": "176baefb2eb5",
"lessThan": "a04c7d062b53",
"status": "affected",
"versionType": "git"
},
{
"version": "176baefb2eb5",
"lessThan": "4fa4302d6dc7",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/cxl/core/region.c"
],
"versions": [
{
"version": "6.0",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.0",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.1.12",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.2",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]