[34-longterm 257/260] gdth: integer overflow in ioctl

[Paul Gortmaker]

From: Dan Carpenter <error27@xxxxxxxxx>

commit f63ae56e4e97fb12053590e41a4fa59e7daa74a4 upstream.

gdth_ioctl_alloc() takes the size variable as an int.
copy_from_user() takes the size variable as an unsigned long.
gen.data_len and gen.sense_len are unsigned longs.
On x86_64 longs are 64 bit and ints are 32 bit.

We could pass in a very large number and the allocation would truncate
the size to 32 bits and allocate a small buffer.  Then when we do the
copy_from_user(), it would result in a memory corruption.

Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/scsi/gdth.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c
index 35a4b30..a8da7e8 100644
--- a/drivers/scsi/gdth.c
+++ b/drivers/scsi/gdth.c
@@ -4175,6 +4175,14 @@ static int ioc_general(void __user *arg, char *cmnd)
     ha = gdth_find_ha(gen.ionode);
     if (!ha)
         return -EFAULT;
+
+    if (gen.data_len > INT_MAX)
+        return -EINVAL;
+    if (gen.sense_len > INT_MAX)
+        return -EINVAL;
+    if (gen.data_len + gen.sense_len > INT_MAX)
+        return -EINVAL;
+
     if (gen.data_len + gen.sense_len != 0) {
         if (!(buf = gdth_ioctl_alloc(ha, gen.data_len + gen.sense_len,
                                      FALSE, &paddr)))
-- 
1.7.3.3

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