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CVE-2026-89515

scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

In the Linux kernel, the following vulnerability has been resolved: scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables() During fuzz testing, the following issue was discovered: BUG: KMSAN: uninit-value in __dma_map_sg_attrs+0x217/0x310 __dma_map_sg_attrs+0x217/0x310 dma_map_sg_attrs+0x4a/0x70 ata_qc_issue+0x9f8/0x1420 __ata_scsi_queuecmd+0x1657/0x1740 ata_scsi_queuecmd+0x79a/0x920 scsi_queue_rq+0x4472/0x4f40 blk_mq_dispatch_rq_list+0x1cca/0x3ee0 __blk_mq_sched_dispatch_requests+0x458/0x630 blk_mq_sched_dispatch_requests+0x15b/0x340 __blk_mq_run_hw_queue+0xe5/0x250 __blk_mq_delay_run_hw_queue+0x138/0x780 blk_mq_run_hw_queue+0x4bb/0x7e0 blk_mq_sched_insert_request+0x2a7/0x4c0 blk_execute_rq+0x497/0x8a0 sg_io+0xbe0/0xe20 scsi_ioctl+0x2b36/0x3c60 sr_block_ioctl+0x319/0x440 blkdev_ioctl+0x80f/0xd70 __se_sys_ioctl+0x219/0x420 __x64_sys_ioctl+0x93/0xe0 x64_sys_call+0x1d6c/0x3ad0 do_syscall_64+0x4c/0xa0 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Uninit was created at: __alloc_pages+0x5c0/0xc80 alloc_pages+0xe0e/0x1050 blk_rq_map_user_iov+0x2b77/0x6100 blk_rq_map_user_io+0x2fa/0x4d0 sg_io+0xad6/0xe20 scsi_ioctl+0x2b36/0x3c60 sr_block_ioctl+0x319/0x440 blkdev_ioctl+0x80f/0xd70 __se_sys_ioctl+0x219/0x420 __x64_sys_ioctl+0x93/0xe0 x64_sys_call+0x1d6c/0x3ad0 do_syscall_64+0x4c/0xa0 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Bytes 14-15 of 16 are uninitialized Memory access of size 16 starts at ffff88800cbdb000 When processing the last unaligned element of the scatterlist, it is supplemented with missing bytes in the amount of pad_len. These bytes remain uninitialized, which leads to a problem. Extend last_sg->length by pad_len first, then use sg_zero_buffer() to zero those pad_len bytes. sg_zero_buffer() uses sg_miter internally, which correctly handles sg entries spanning multiple pages and padding that crosses a page boundary. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in 1aa6df61cef1f47f503c3ccf60d08c4dd931fdc1; From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in 6da140ebdfdd6aa3773945f2c0ebba01d2ef33d8; From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in fd2cbe08c6ccba7fc1ddb830653a93bb7e2d833c; From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in 28ed5343666ff424ce5e248fa1c5a402303b4aff; From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in a4353ec7742bdf87dcdde5875270feb3a1982a51; From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in e7143c3f4e5c0a7986733c6f27009274bf6c4264; From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in 6fd1cce5018fdcc8d928e00a6a1dd2997d5b9409; From 40b01b9bbdf51ae543a04744283bf2d56c4a6afa · fixed in 626147717bea776b61ed3631d2c26283760c4cc4

  • Linux Linux

    2.6.25

  • KernelLinux

    From 2.6.25 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8

git.kernel.org