scsi: bfa: integer overflow in debugfs

[ 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.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/bfa/bfad_debugfs.c b/drivers/scsi/bfa/bfad_debugfs.c
index 74a307c0a2407c45af6ad42796d4944a3bec2bed..8f1c58d4d5b5cd51eef59719b07e723ea90dbe1f 100644 (file)
--- a/drivers/scsi/bfa/bfad_debugfs.c
+++ b/drivers/scsi/bfa/bfad_debugfs.c
@@ -254,7 +254,8 @@ 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;
@@ -265,7 +266,7 @@ 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__);