openwrt/target/linux/mvebu/patches-3.10/0191-of-irq-Fix-potential-buffer-overflow.patch

From 5a1bd82f089e19ba049a871a0d5538ed9eb5e5cd Mon Sep 17 00:00:00 2001
From: Grant Likely <grant.likely@linaro.org>
Date: Thu, 19 Dec 2013 09:31:02 -0300
Subject: [PATCH 191/203] of/irq: Fix potential buffer overflow

Commit 2361613206e6, "of/irq: Refactor interrupt-map parsing" introduced
a potential buffer overflow bug because it doesn't do sufficient range
checking on the input data. This patch adds the appropriate checking and
buffer size adjustments. If the bounds are out of range then warn
loudly. MAX_PHANDLE_ARGS should be sufficient. If it is not then the
value can be increased.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
---
 drivers/of/irq.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -95,9 +95,9 @@ struct device_node *of_irq_find_parent(s
 int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
 {
 	struct device_node *ipar, *tnode, *old = NULL, *newpar = NULL;
-	__be32 initial_match_array[8];
+	__be32 initial_match_array[MAX_PHANDLE_ARGS];
 	const __be32 *match_array = initial_match_array;
-	const __be32 *tmp, *imap, *imask, dummy_imask[] = { ~0, ~0, ~0, ~0, ~0 };
+	const __be32 *tmp, *imap, *imask, dummy_imask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
 	u32 intsize = 1, addrsize, newintsize = 0, newaddrsize = 0;
 	int imaplen, match, i;
 
@@ -147,6 +147,10 @@ int of_irq_parse_raw(const __be32 *addr,
 
 	pr_debug(" -> addrsize=%d\n", addrsize);
 
+	/* Range check so that the temporary buffer doesn't overflow */
+	if (WARN_ON(addrsize + intsize > MAX_PHANDLE_ARGS))
+		goto fail;
+
 	/* Precalculate the match array - this simplifies match loop */
 	for (i = 0; i < addrsize; i++)
 		initial_match_array[i] = addr ? addr[i] : 0;
@@ -229,6 +233,8 @@ int of_irq_parse_raw(const __be32 *addr,
 			    newintsize, newaddrsize);
 
 			/* Check for malformed properties */
+			if (WARN_ON(newaddrsize + newintsize > MAX_PHANDLE_ARGS))
+				goto fail;
 			if (imaplen < (newaddrsize + newintsize))
 				goto fail;