Commit 4e57e0b9 authored May 20, 2020 by James Smart Committed by Christoph Hellwig May 27, 2020

lpfc: fix axchg pointer reference after free and double frees



The axchg structure is a structure allocated early in the
lpfc_nvme_unsol_ls_handler() to represent the newly received exchange.
Upon error, the out_fail path in the routine unconditionally frees the
pointer, yet subsequently passes the pointer to the abort routine.
Additionally, the abort routine, lpfc_nvme_unsol_ls_issue_abort(), also
has a failure path that will attempt to delete the pointer on error.

Fix these errors by:
- Removing the unconditional free so that it stays valid if passed
  to the abort routine.
- Revise the abort routine to not free the pointer. Instead, return
  a success/failure status. Note: if success, the later completion of
  the abort frees the structure.
- Back in the unsol_ls_handler() error path, if the abort routine was
  skipped (thus no possible reference) or the abort routine returned
  error, free the pointer.

Fixes: 3a8070c5 ("lpfc: Refactor NVME LS receive handling")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent fcdd14b8

drivers/scsi/lpfc/lpfc_nvmet.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -3598,10 +3598,9 @@ out:
		abts_wqeq->context2 = NULL;
		abts_wqeq->context3 = NULL;
		lpfc_sli_release_iocbq(phba, abts_wqeq);
		kfree(ctxp);
		lpfc_printf_log(phba, KERN_ERR, LOG_NVME_ABTS,
		"6056 Failed to Issue ABTS. Status x%x\n", rc);
		return 0;
		return 1;
		}

		/**

drivers/scsi/lpfc/lpfc_sli.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -2813,7 +2813,7 @@ lpfc_nvme_unsol_ls_handler(struct lpfc_hba phba, struct lpfc_iocbq piocb)
		struct lpfc_async_xchg_ctx *axchg = NULL;
		char *failwhy = NULL;
		uint32_t oxid, sid, did, fctl, size;
		int ret;
		int ret = 1;

		d_buf = piocb->context2;

		@@ -2897,14 +2897,16 @@ lpfc_nvme_unsol_ls_handler(struct lpfc_hba phba, struct lpfc_iocbq piocb)
		(phba->nvmet_support) ? "T" : "I", ret);

		out_fail:
		kfree(axchg);

		/* recycle receive buffer */
		lpfc_in_buf_free(phba, &nvmebuf->dbuf);

		/* If start of new exchange, abort it */
		if (fctl & FC_FC_FIRST_SEQ && !(fctl & FC_FC_EX_CTX))
		lpfc_nvme_unsol_ls_issue_abort(phba, axchg, sid, oxid);
		if (axchg && (fctl & FC_FC_FIRST_SEQ && !(fctl & FC_FC_EX_CTX)))
		ret = lpfc_nvme_unsol_ls_issue_abort(phba, axchg, sid, oxid);

		if (ret)
		kfree(axchg);
		}

		/**

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