[PATCH 4.4 110/115] scsi: bfa: integer overflow in debugfs

Greg Kroah-Hartman
2017-12-18T15:57:23Z

From: Dan Carpenter <dan.carpenter@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.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>
---
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
@@ -254,7 +254,8 @@ 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;
@@ -265,7 +266,7 @@ bfad_debugfs_write_regrd(struct file *fi
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__);