sym53c8xx: Fix NULL pointer dereference in slave_destroy

commit cced5041ed5a2d1352186510944b0ddfbdbe4c0b upstream.

sym53c8xx_slave_destroy unconditionally assumes that sym53c8xx_slave_alloc has
succesesfully allocated a sym_lcb. This can lead to a NULL pointer dereference
(exposed by commit 4e6c82b).

Signed-off-by: Stratos Psomadakis <psomas@gentoo.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index d39107b7669bfb22e3fa1e278166dd2c2766616f..8dfc3853fd49312550f884f16420bafee65dadb4 100644 (file)
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -821,6 +821,10 @@ static void sym53c8xx_slave_destroy(struct scsi_device *sdev)
        struct sym_hcb *np = sym_get_hcb(sdev->host);
        struct sym_lcb *lp = sym_lp(&np->target[sdev->id], sdev->lun);
 
+       /* if slave_alloc returned before allocating a sym_lcb, return */
+       if (!lp)
+               return;
+
        if (lp->itlq_tbl)
                sym_mfree_dma(lp->itlq_tbl, SYM_CONF_MAX_TASK * 4, "ITLQ_TBL");
        kfree(lp->cb_tags);