[PATCH AUTOSEL for 4.9 150/156] scsi: bfa: integer overflow in debugfs

[alexander . levin]

From: Dan Carpenter <dan.carpen...@oracle.com>

[ Upstream commit 3e351275655d3c84dc28abf170def9786db5176d ]

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.carpen...@oracle.com>
Signed-off-by: Martin K. Petersen <martin.peter...@oracle.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
---
 drivers/scsi/bfa/bfad_debugfs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/bfa/bfad_debugfs.c b/drivers/scsi/bfa/bfad_debugfs.c
index 8dcd8c70c7ee..05f523971348 100644
--- a/drivers/scsi/bfa/bfad_debugfs.c
+++ b/drivers/scsi/bfa/bfad_debugfs.c
@@ -255,7 +255,8 @@ bfad_debugfs_write_regrd(struct file *file, const char 
__user *buf,
        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;
@@ -266,7 +267,7 @@ bfad_debugfs_write_regrd(struct file *file, const char 
__user *buf,
                return PTR_ERR(kern_buf);
 
        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__);
-- 
2.11.0