nvmet-fc: fix invalid free in LS IOD error path

Overview

In the Linux kernel, the following vulnerability has been resolved:

nvmet-fc: fix invalid free in LS IOD error path

nvmet_fc_alloc_ls_iodlist() advances iod while initializing the LS IOD array. If an rqstbuf allocation or response buffer DMA mapping fails, the unwind loop decrements iod past the start of the array. The final kfree(iod) therefore frees an address before the allocated object.

This can be reproduced with nvme-fcloop and failslab by setting fail-nth to 6 before creating a target port. KASAN reports:

BUG: KASAN: invalid-free in nvmet_fc_register_targetport Free of addr ffff88816cf8ff48 by task nvmet_fail_nth/9552

Free the original allocation base stored in tgtport->iod instead. With this fix applied, the same sysfs write with fail-nth=6 returns -ENOMEM without any KASAN report.

Affected

• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < b189c6e408896ccc23d2e76d7738847cdebf1532
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < 449e9c4f8db84ad9d9bb288029b230bcf590faa2
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < 1a8f007faefe8c226ec65896589f8d59b0a8d5a5
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < d094582cce9c08516d714e7436a8f3b9211dda90
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < 371fb1bf902adaa59be32bd7e904a5317e604fd0
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < 8bce9cd08aae4283badf8ddc11fbb6f57b75a81e
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < bb9489f0dce58da730d3479588d6710d7a2c1b45
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < 94334ea92f4d7535f66f86e33681efa94827eddc
• Linux >= c53432030d86429dc9fe5adc3d68cb9d1343b0b2 < ba98d6796d12258e837ece065d2ecb59d76ce4ff
• Linux 4.10

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.