nbd: fix incomplete validation of ioctl arg
We tested and found an alarm caused by nbd_ioctl arg without verification.
The UBSAN warning calltrace like below:
UBSAN: Undefined behaviour in fs/buffer.c:1709:35
signed integer overflow:
-9223372036854775808 - 1 cannot be represented in type 'long long int'
CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x170/0x1dc lib/dump_stack.c:118
ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
handle_overflow+0x188/0x1dc lib/ubsan.c:192
__ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
__block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
blkdev_writepage+0x34/0x40 fs/block_dev.c:607
__writepage+0x68/0xe8 mm/page-writeback.c:2305
write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
do_writepages+0xd4/0x250 mm/page-writeback.c:2344
The reason for triggering this warning is __block_write_full_page()
-> i_size_read(inode) - 1 overflow.
inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.
We think it is necessary to limit the size of arg to prevent errors.
Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine),
it will become 1 after the coercion, which will return unexpected results.
Fix it by adding checks to prevent passing in too large numbers.
No analysis available yet.
No remediation available yet.
Tracking
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| Source | ID | Title |
|---|---|---|
EUVD |
EUVD-2025-31880 |
Mon, 26 Jan 2026 20:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-674 | |
| Metrics |
cvssV3_1
|
cvssV3_1
|
Mon, 05 Jan 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
Thu, 02 Oct 2025 09:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Thu, 02 Oct 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Wed, 01 Oct 2025 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: nbd: fix incomplete validation of ioctl arg We tested and found an alarm caused by nbd_ioctl arg without verification. The UBSAN warning calltrace like below: UBSAN: Undefined behaviour in fs/buffer.c:1709:35 signed integer overflow: -9223372036854775808 - 1 cannot be represented in type 'long long int' CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78 show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x170/0x1dc lib/dump_stack.c:118 ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161 handle_overflow+0x188/0x1dc lib/ubsan.c:192 __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206 __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709 block_write_full_page+0x1f0/0x280 fs/buffer.c:2934 blkdev_writepage+0x34/0x40 fs/block_dev.c:607 __writepage+0x68/0xe8 mm/page-writeback.c:2305 write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240 generic_writepages+0xdc/0x148 mm/page-writeback.c:2329 blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114 do_writepages+0xd4/0x250 mm/page-writeback.c:2344 The reason for triggering this warning is __block_write_full_page() -> i_size_read(inode) - 1 overflow. inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize. We think it is necessary to limit the size of arg to prevent errors. Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int. Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine), it will become 1 after the coercion, which will return unexpected results. Fix it by adding checks to prevent passing in too large numbers. | |
| Title | nbd: fix incomplete validation of ioctl arg | |
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-01-05T10:21:04.790Z
Reserved: 2025-10-01T11:39:39.406Z
Link: CVE-2023-53513
No data.
Status : Analyzed
Published: 2025-10-01T12:15:55.317
Modified: 2026-01-26T20:11:49.407
Link: CVE-2023-53513
OpenCVE Enrichment
Updated: 2025-10-02T08:38:35Z
EUVD