From: Frank Rowand <frank.rowand@sony.com>
Date: Thu, 17 May 2018 04:19:51 +0000 (-0700)
Subject: of: overlay: validate offset from property fixups
X-Git-Tag: v4.14.53~104
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4910cc250b4dab82b42a743377d359abaee07b73;p=users%2Fjedix%2Flinux-maple.git

of: overlay: validate offset from property fixups

commit 482137bf2aecd887ebfa8756456764a2f6a0e545 upstream.

The smatch static checker marks the data in offset as untrusted,
leading it to warn:

  drivers/of/resolver.c:125 update_usages_of_a_phandle_reference()
  error: buffer underflow 'prop->value' 's32min-s32max'

Add check to verify that offset is within the property data.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
index 99309cb7d3724..3bf4b6489fd05 100644
--- a/drivers/of/resolver.c
+++ b/drivers/of/resolver.c
@@ -129,6 +129,11 @@ static int update_usages_of_a_phandle_reference(struct device_node *overlay,
 			goto err_fail;
 		}
 
+		if (offset < 0 || offset + sizeof(__be32) > prop->length) {
+			err = -EINVAL;
+			goto err_fail;
+		}
+
 		*(__be32 *)(prop->value + offset) = cpu_to_be32(phandle);
 	}