driver inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I3BNT6 CVE: NA

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We can get a crash when disconnecting the iSCSI session, the call trace like this:

[ffff00002a00fb70] kfree at ffff00000830e224 [ffff00002a00fba0] ses_intf_remove at ffff000001f200e4 [ffff00002a00fbd0] device_del at ffff0000086b6a98 [ffff00002a00fc50] device_unregister at ffff0000086b6d58 [ffff00002a00fc70] __scsi_remove_device at ffff00000870608c [ffff00002a00fca0] scsi_remove_device at ffff000008706134 [ffff00002a00fcc0] __scsi_remove_target at ffff0000087062e4 [ffff00002a00fd10] scsi_remove_target at ffff0000087064c0 [ffff00002a00fd70] __iscsi_unbind_session at ffff000001c872c4 [ffff00002a00fdb0] process_one_work at ffff00000810f35c [ffff00002a00fe00] worker_thread at ffff00000810f648 [ffff00002a00fe70] kthread at ffff000008116e98

In ses_intf_add, components count could be 0, and kcalloc 0 size scomp, but not saved in edev->component[i].scratch

In this situation, edev->component[0].scratch is an invalid pointer, when kfree it in ses_intf_remove_enclosure, a crash like above would happen The call trace also could be other random cases when kfree cannot catch the invalid pointer

We should not use edev->component[] array when the components count is 0 We also need check index when use edev->component[] array in ses_enclosure_data_process

Another fix option is report error and do not attach in ses_intf_add if we meet a zero component enclosure

Tested-by: Zeng Zhicong timmyzeng@163.com Signed-off-by: Ding Hui dinghui@sangfor.com.cn --- drivers/scsi/ses.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c index 0fc39224ce1e..63764fe0b34f 100644 --- a/drivers/scsi/ses.c +++ b/drivers/scsi/ses.c @@ -493,9 +493,6 @@ static int ses_enclosure_find_by_addr(struct enclosure_device *edev, int i; struct ses_component *scomp;

- if (!edev->component[0].scratch) - return 0; - for (i = 0; i < edev->components; i++) { scomp = edev->component[i].scratch; if (scomp->addr != efd->addr) @@ -581,8 +578,10 @@ static void ses_enclosure_data_process(struct enclosure_device *edev, components++, type_ptr[0], name); - else + else if (components < edev->components) ecomp = &edev->component[components++]; + else + ecomp = ERR_PTR(-EINVAL);

if (!IS_ERR(ecomp)) { if (addl_desc_ptr) @@ -747,9 +746,11 @@ static int ses_intf_add(struct device *cdev, buf = NULL; } page2_not_supported: - scomp = kcalloc(components, sizeof(struct ses_component), GFP_KERNEL); - if (!scomp) - goto err_free; + if (components > 0) { + scomp = kcalloc(components, sizeof(struct ses_component), GFP_KERNEL); + if (!scomp) + goto err_free; + }

edev = enclosure_register(cdev->parent, dev_name(&sdev->sdev_gendev), components, &ses_enclosure_callbacks); @@ -829,7 +830,8 @@ static void ses_intf_remove_enclosure(struct scsi_device *sdev) kfree(ses_dev->page2); kfree(ses_dev);

- kfree(edev->component[0].scratch); + if (edev->components > 0) + kfree(edev->component[0].scratch);

put_device(&edev->edev); enclosure_unregister(edev);