416baaa9-dc9f-4396-8d5f-8c081fb06d67CVE-2021-46986CVE-2021-46986
In the Linux kernel, the following vulnerability has been resolved:
usb: dwc3: gadget: Free gadget structure only after freeing endpoints
As part of commit e81a7018d93a (“usb: dwc3: allocate gadget structure
dynamically”) the dwc3_gadget_release() was added which will free
the dwc->gadget structure upon the device’s removal when
usb_del_gadget_udc() is called in dwc3_gadget_exit().
However, simply freeing the gadget results a dangling pointer
situation: the endpoints created in dwc3_gadget_init_endpoints()
have their dep->endpoint.ep_list members chained off the list_head
anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,
the first dwc3_ep in the list now has a dangling prev pointer and
likewise for the next pointer of the dwc3_ep at the tail of the list.
The dwc3_gadget_free_endpoints() that follows will result in a
use-after-free when it calls list_del().
This was caught by enabling KASAN and performing a driver unbind.
The recent commit 568262bf5492 (“usb: dwc3: core: Add shutdown
callback for dwc3”) also exposes this as a panic during shutdown.
There are a few possibilities to fix this. One could be to perform
a list_del() of the gadget->ep_list itself which removes it from
the rest of the dwc3_ep chain.
Another approach is what this patch does, by splitting up the
usb_del_gadget_udc() call into its separate “del” and “put”
components. This allows dwc3_gadget_free_endpoints() to be
called before the gadget is finally freed with usb_put_gadget().
Affected configurations
| Vendor | Product | Version | CPE |
|---|---|---|---|
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
CNA Affected
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/usb/dwc3/gadget.c"
],
"versions": [
{
"version": "e81a7018d93a",
"lessThan": "1ea775021282",
"status": "affected",
"versionType": "git"
},
{
"version": "e81a7018d93a",
"lessThan": "bc0cdd724932",
"status": "affected",
"versionType": "git"
},
{
"version": "e81a7018d93a",
"lessThan": "b4b8e9601d7e",
"status": "affected",
"versionType": "git"
},
{
"version": "e81a7018d93a",
"lessThan": "bb9c74a5bd14",
"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/usb/dwc3/gadget.c"
],
"versions": [
{
"version": "5.10",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.10",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.10.38",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.11.22",
"lessThanOrEqual": "5.11.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.12.5",
"lessThanOrEqual": "5.12.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.13",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]Related
