From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 4 Oct 2017 10:50:37 +0300
Subject: scsi: bfa: integer overflow in debugfs
Git-commit: 3e351275655d3c84dc28abf170def9786db5176d
Patch-mainline: v4.15-rc1
References: bsc#1115832

We could allocate less memory than intended because we do:

	bfad->regdata = kzalloc(len << 2, GFP_KERNEL);

The shift can overflow leading to a crash.  This is debugfs code so the
impact is very small.  I fixed the network version of this in March with
commit 13e2d5187f6b ("bna: integer overflow bug in debugfs").

Fixes: ab2a9ba189e8 ("[SCSI] bfa: add debugfs support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Lee Duncan <lduncan@suse.com>
---
 drivers/scsi/bfa/bfad_debugfs.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/scsi/bfa/bfad_debugfs.c
+++ b/drivers/scsi/bfa/bfad_debugfs.c
@@ -275,7 +275,8 @@ bfad_debugfs_write_regrd(struct file *fi
 	struct bfad_s *bfad = port->bfad;
 	struct bfa_s *bfa = &bfad->bfa;
 	struct bfa_ioc_s *ioc = &bfa->ioc;
-	int addr, len, rc, i;
+	int addr, rc, i;
+	u32 len;
 	u32 *regbuf;
 	void __iomem *rb, *reg_addr;
 	unsigned long flags;
@@ -295,7 +296,7 @@ bfad_debugfs_write_regrd(struct file *fi
 	}
 
 	rc = sscanf(kern_buf, "%x:%x", &addr, &len);
-	if (rc < 2) {
+	if (rc < 2 || len > (UINT_MAX >> 2)) {
 		printk(KERN_INFO
 			"bfad[%d]: %s failed to read user buf\n",
 			bfad->inst_no, __func__);

