[PATCH 4.14 112/115] drivers/virt/fsl_hypervisor.c: dereferencing error pointers in ioctl

Greg Kroah-Hartman
2019-05-15T11:20:33Z

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

commit c8ea3663f7a8e6996d44500ee818c9330ac4fd88 upstream.

strndup_user() returns error pointers on error, and then in the error
handling we pass the error pointers to kfree(). It will cause an Oops.

Link: http://lkml.kernel.org/r/20181218082003.GD32567@kadam
Fixes: 6db7199407ca ("drivers/virt: introduce Freescale hypervisor management driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Timur Tabi <timur@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/virt/fsl_hypervisor.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)

--- a/drivers/virt/fsl_hypervisor.c
+++ b/drivers/virt/fsl_hypervisor.c
@@ -331,8 +331,8 @@ static long ioctl_dtprop(struct fsl_hv_i
struct fsl_hv_ioctl_prop param;
char __user *upath, *upropname;
void __user *upropval;
- char *path = NULL, *propname = NULL;
- void *propval = NULL;
+ char *path, *propname;
+ void *propval;
int ret = 0;

/* Get the parameters from the user. */
@@ -344,32 +344,30 @@ static long ioctl_dtprop(struct fsl_hv_i
upropval = (void __user *)(uintptr_t)param.propval;

path = strndup_user(upath, FH_DTPROP_MAX_PATHLEN);
- if (IS_ERR(path)) {
- ret = PTR_ERR(path);
- goto out;
- }
+ if (IS_ERR(path))
+ return PTR_ERR(path);

propname = strndup_user(upropname, FH_DTPROP_MAX_PATHLEN);
if (IS_ERR(propname)) {
ret = PTR_ERR(propname);
- goto out;
+ goto err_free_path;
}

if (param.proplen > FH_DTPROP_MAX_PROPLEN) {
ret = -EINVAL;
- goto out;
+ goto err_free_propname;
}

propval = kmalloc(param.proplen, GFP_KERNEL);
if (!propval) {
ret = -ENOMEM;
- goto out;
+ goto err_free_propname;
}

if (set) {
if (copy_from_user(propval, upropval, param.proplen)) {
ret = -EFAULT;
- goto out;
+ goto err_free_propval;
}

param.ret = fh_partition_set_dtprop(param.handle,
@@ -388,7 +386,7 @@ static long ioctl_dtprop(struct fsl_hv_i
if (copy_to_user(upropval, propval, param.proplen) ||
put_user(param.proplen, &p->proplen)) {
ret = -EFAULT;
- goto out;
+ goto err_free_propval;
}
}
}
@@ -396,10 +394,12 @@ static long ioctl_dtprop(struct fsl_hv_i
if (put_user(param.ret, &p->ret))
ret = -EFAULT;

-out:
- kfree(path);
+err_free_propval:
kfree(propval);
+err_free_propname:
kfree(propname);
+err_free_path:
+ kfree(path);

return ret;
}