| Description | In the Linux kernel, the following vulnerability has been resolved:  scsi: ses: Handle enclosure with just a primary component gracefully  This reverts commit 3fe97ff3d949 ("scsi: ses: Don't attach if enclosure has no components") and introduces proper handling of case where there are no detected secondary components, but primary component (enumerated in num_enclosures) does exist. That fix was originally proposed by Ding Hui <dinghui@sangfor.com.cn>.  Completely ignoring devices that have one primary enclosure and no secondary one results in ses_intf_add() bailing completely  	scsi 2:0:0:254: enclosure has no enumerated components         scsi 2:0:0:254: Failed to bind enclosure -12ven in valid configurations such  even on valid configurations with 1 primary and 0 secondary enclosures as below:  	# sg_ses /dev/sg0 	  3PARdata  SES               3321 	Supported diagnostic pages: 	  Supported Diagnostic Pages [sdp] [0x0] 	  Configuration (SES) [cf] [0x1] 	  Short Enclosure Status (SES) [ses] [0x8] 	# sg_ses -p cf /dev/sg0 	  3PARdata  SES               3321 	Configuration diagnostic page: 	  number of secondary subenclosures: 0 	  generation code: 0x0 	  enclosure descriptor list 	    Subenclosure identifier: 0 [primary] 	      relative ES process id: 0, number of ES processes: 1 	      number of type descriptor headers: 1 	      enclosure logical identifier (hex): 20000002ac02068d 	      enclosure vendor: 3PARdata  product: VV                rev: 3321 	  type descriptor header and text list 	    Element type: Unspecified, subenclosure id: 0 	      number of possible elements: 1  The changelog for the original fix follows  ===== 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 ===== |