CVE-2023-52894
Linux Kernel USB Gadget NULL Pointer Dereference Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate() In Google internal bug 265639009 we've received an (as yet) unreproducible crash report from an aarch64 GKI 5.10.149-android13 running device. AFAICT the source code is at: https://android.googlesource.com/kernel/common/+/refs/tags/ASB-2022-12-05_13-5.10 The call stack is: ncm_close() -> ncm_notify() -> ncm_do_notify() with the crash at: ncm_do_notify+0x98/0x270 Code: 79000d0b b9000a6c f940012a f9400269 (b9405d4b) Which I believe disassembles to (I don't know ARM assembly, but it looks sane enough to me...): // halfword (16-bit) store presumably to event->wLength (at offset 6 of struct usb_cdc_notification) 0B 0D 00 79 strh w11, [x8, #6] // word (32-bit) store presumably to req->Length (at offset 8 of struct usb_request) 6C 0A 00 B9 str w12, [x19, #8] // x10 (NULL) was read here from offset 0 of valid pointer x9 // IMHO we're reading 'cdev->gadget' and getting NULL // gadget is indeed at offset 0 of struct usb_composite_dev 2A 01 40 F9 ldr x10, [x9] // loading req->buf pointer, which is at offset 0 of struct usb_request 69 02 40 F9 ldr x9, [x19] // x10 is null, crash, appears to be attempt to read cdev->gadget->max_speed 4B 5D 40 B9 ldr w11, [x10, #0x5c] which seems to line up with ncm_do_notify() case NCM_NOTIFY_SPEED code fragment: event->wLength = cpu_to_le16(8); req->length = NCM_STATUS_BYTECOUNT; /* SPEED_CHANGE data is up/down speeds in bits/sec */ data = req->buf + sizeof *event; data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget)); My analysis of registers and NULL ptr deref crash offset (Unable to handle kernel NULL pointer dereference at virtual address 000000000000005c) heavily suggests that the crash is due to 'cdev->gadget' being NULL when executing: data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget)); which calls: ncm_bitrate(NULL) which then calls: gadget_is_superspeed(NULL) which reads ((struct usb_gadget *)NULL)->max_speed and hits a panic. AFAICT, if I'm counting right, the offset of max_speed is indeed 0x5C. (remember there's a GKI KABI reservation of 16 bytes in struct work_struct) It's not at all clear to me how this is all supposed to work... but returning 0 seems much better than panic-ing...
INFO
Published Date :
Aug. 21, 2024, 7:15 a.m.
Last Modified :
Sept. 11, 2024, 4:27 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
3.6
Exploitability Score :
1.8
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2023-52894.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2023-52894 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2023-52894 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Sep. 11, 2024
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Changed Reference Type https://git.kernel.org/stable/c/09e4507ec8ef2d44da6ba4092b8ee2d81f216497 No Types Assigned https://git.kernel.org/stable/c/09e4507ec8ef2d44da6ba4092b8ee2d81f216497 Patch Changed Reference Type https://git.kernel.org/stable/c/63d161f29cd39c050e8873aa36e0c9fc013bb763 No Types Assigned https://git.kernel.org/stable/c/63d161f29cd39c050e8873aa36e0c9fc013bb763 Patch Changed Reference Type https://git.kernel.org/stable/c/a21da7f7aae618c785f7e4a275d43c06dc8412b6 No Types Assigned https://git.kernel.org/stable/c/a21da7f7aae618c785f7e4a275d43c06dc8412b6 Patch Changed Reference Type https://git.kernel.org/stable/c/a69c8dfb85b44be9cc223be07d35cc3a9baefbea No Types Assigned https://git.kernel.org/stable/c/a69c8dfb85b44be9cc223be07d35cc3a9baefbea Patch Changed Reference Type https://git.kernel.org/stable/c/c6ec929595c7443250b2a4faea988c62019d5cd2 No Types Assigned https://git.kernel.org/stable/c/c6ec929595c7443250b2a4faea988c62019d5cd2 Patch Changed Reference Type https://git.kernel.org/stable/c/e92c70059178da751e5af7de02384b7dfadb5ec7 No Types Assigned https://git.kernel.org/stable/c/e92c70059178da751e5af7de02384b7dfadb5ec7 Patch Changed Reference Type https://git.kernel.org/stable/c/fef6b29671b66dfb71f17e337c1ad14b5a2cedae No Types Assigned https://git.kernel.org/stable/c/fef6b29671b66dfb71f17e337c1ad14b5a2cedae Patch Added CWE NIST CWE-476 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions up to (excluding) 4.14.304 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.15 up to (excluding) 4.19.271 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.20 up to (excluding) 5.4.230 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.5 up to (excluding) 5.10.165 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.90 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.8 *cpe:2.3:o:linux:linux_kernel:6.2:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.2:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.2:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.2:rc4:*:*:*:*:*:* -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 21, 2024
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate() In Google internal bug 265639009 we've received an (as yet) unreproducible crash report from an aarch64 GKI 5.10.149-android13 running device. AFAICT the source code is at: https://android.googlesource.com/kernel/common/+/refs/tags/ASB-2022-12-05_13-5.10 The call stack is: ncm_close() -> ncm_notify() -> ncm_do_notify() with the crash at: ncm_do_notify+0x98/0x270 Code: 79000d0b b9000a6c f940012a f9400269 (b9405d4b) Which I believe disassembles to (I don't know ARM assembly, but it looks sane enough to me...): // halfword (16-bit) store presumably to event->wLength (at offset 6 of struct usb_cdc_notification) 0B 0D 00 79 strh w11, [x8, #6] // word (32-bit) store presumably to req->Length (at offset 8 of struct usb_request) 6C 0A 00 B9 str w12, [x19, #8] // x10 (NULL) was read here from offset 0 of valid pointer x9 // IMHO we're reading 'cdev->gadget' and getting NULL // gadget is indeed at offset 0 of struct usb_composite_dev 2A 01 40 F9 ldr x10, [x9] // loading req->buf pointer, which is at offset 0 of struct usb_request 69 02 40 F9 ldr x9, [x19] // x10 is null, crash, appears to be attempt to read cdev->gadget->max_speed 4B 5D 40 B9 ldr w11, [x10, #0x5c] which seems to line up with ncm_do_notify() case NCM_NOTIFY_SPEED code fragment: event->wLength = cpu_to_le16(8); req->length = NCM_STATUS_BYTECOUNT; /* SPEED_CHANGE data is up/down speeds in bits/sec */ data = req->buf + sizeof *event; data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget)); My analysis of registers and NULL ptr deref crash offset (Unable to handle kernel NULL pointer dereference at virtual address 000000000000005c) heavily suggests that the crash is due to 'cdev->gadget' being NULL when executing: data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget)); which calls: ncm_bitrate(NULL) which then calls: gadget_is_superspeed(NULL) which reads ((struct usb_gadget *)NULL)->max_speed and hits a panic. AFAICT, if I'm counting right, the offset of max_speed is indeed 0x5C. (remember there's a GKI KABI reservation of 16 bytes in struct work_struct) It's not at all clear to me how this is all supposed to work... but returning 0 seems much better than panic-ing... Added Reference kernel.org https://git.kernel.org/stable/c/fef6b29671b66dfb71f17e337c1ad14b5a2cedae [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/63d161f29cd39c050e8873aa36e0c9fc013bb763 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/a21da7f7aae618c785f7e4a275d43c06dc8412b6 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/e92c70059178da751e5af7de02384b7dfadb5ec7 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/a69c8dfb85b44be9cc223be07d35cc3a9baefbea [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/09e4507ec8ef2d44da6ba4092b8ee2d81f216497 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/c6ec929595c7443250b2a4faea988c62019d5cd2 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2023-52894 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2023-52894
weaknesses.