net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2023-53667
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-10-07 16:15:50 UTC
Updated2026-11-05 21:17:31 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize Currently in cdc_ncm_check_tx_max(), if dwNtbOutMaxSize is lower than the calculated "min" value, but greater than zero, the logic sets tx_max to dwNtbOutMaxSize. This is then used to allocate a new SKB in cdc_ncm_fill_tx_frame() where all the data is handled. For small values of dwNtbOutMaxSize the memory allocated during alloc_skb(dwNtbOutMaxSize, GFP_ATOMIC) will have the same size, due to how size is aligned at alloc time: size = SKB_DATA_ALIGN(size); size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); Thus we hit the same bug that we tried to squash with commit 2be6d4d16a084 ("net: cdc_ncm: Allow for dwNtbOutMaxSize to be unset or zero") Low values of dwNtbOutMaxSize do not cause an issue presently because at alloc_skb() time more memory (512b) is allocated than required for the SKB headers alone (320b), leaving some space (512b - 320b = 192b) for CDC data (172b). However, if more elements (for example 3 x u64 = [24b]) were added to one of the SKB header structs, say 'struct skb_shared_info', increasing its original size (320b [320b aligned]) to something larger (344b [384b aligned]), then suddenly the CDC data (172b) no longer fits in the spare SKB data area (512b - 384b = 128b). Consequently the SKB bounds checking semantics fails and panics: skbuff: skb_over_panic: text:ffffffff831f755b len:184 put:172 head:ffff88811f1c6c00 data:ffff88811f1c6c00 tail:0xb8 end:0x80 dev:<NULL> ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:113! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 57 Comm: kworker/0:2 Not tainted 5.15.106-syzkaller-00249-g19c0ed55a470 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Workqueue: mld mld_ifc_work RIP: 0010:skb_panic net/core/skbuff.c:113 [inline] RIP: 0010:skb_over_panic+0x14c/0x150 net/core/skbuff.c:118 [snip] Call Trace: <TASK> skb_put+0x151/0x210 net/core/skbuff.c:2047 skb_put_zero include/linux/skbuff.h:2422 [inline] cdc_ncm_ndp16 drivers/net/usb/cdc_ncm.c:1131 [inline] cdc_ncm_fill_tx_frame+0x11ab/0x3da0 drivers/net/usb/cdc_ncm.c:1308 cdc_ncm_tx_fixup+0xa3/0x100 Deal with too low values of dwNtbOutMaxSize, clamp it in the range [USB_CDC_NCM_NTB_MIN_OUT_SIZE, CDC_NCM_NTB_MAX_SIZE_TX]. We ensure enough data space is allocated to handle CDC data by making sure dwNtbOutMaxSize is not smaller than USB_CDC_NCM_NTB_MIN_OUT_SIZE.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-476

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 2334ff0b343ba6ba7a6c0586fcc83992bbbc1776 git Not specified
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 bf415bfe7573596ac213b4fd1da9e62cfc9a9413 git Not specified
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 ff484163dfb61b58f23e4dbd007de1094427669c git Not specified
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 42b78c8cc774b47023d6d16d96d54cc7015e4a07 git Not specified
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 9be921854e983a81a0aeeae5febcd87093086e46 git Not specified
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 6147745d43ff4e0d2c542e5b93e398ef0ee4db00 git Not specified
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 72d0240b0ee4794efc683975c213e4b384fea733 git Not specified
CNA Linux Linux affected 289507d3364f96f4b8814726917d572f71350d87 7e01c7f7046efc2c7c192c3619db43292b98e997 git Not specified
CNA Linux Linux affected 3.16 Not specified
CNA Linux Linux unaffected 3.16 semver Not specified
CNA Linux Linux unaffected 4.14.317 4.14.* semver Not specified
CNA Linux Linux unaffected 4.19.285 4.19.* semver Not specified
CNA Linux Linux unaffected 5.4.245 5.4.* semver Not specified
CNA Linux Linux unaffected 5.10.181 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.114 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.31 6.1.* semver Not specified
CNA Linux Linux unaffected 6.3.5 6.3.* semver Not specified
CNA Linux Linux unaffected 6.4 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/bf415bfe7573596ac213b4fd1da9e62cfc9a9413 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/6147745d43ff4e0d2c542e5b93e398ef0ee4db00 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/ff484163dfb61b58f23e4dbd007de1094427669c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/9be921854e983a81a0aeeae5febcd87093086e46 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/72d0240b0ee4794efc683975c213e4b384fea733 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/7e01c7f7046efc2c7c192c3619db43292b98e997 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/2334ff0b343ba6ba7a6c0586fcc83992bbbc1776 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/42b78c8cc774b47023d6d16d96d54cc7015e4a07 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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