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From: Stefan Kerkmann <s.kerkmann@pengutronix.de>
To: Sascha Hauer <s.hauer@pengutronix.de>,
	 BAREBOX <barebox@lists.infradead.org>
Cc: Stefan Kerkmann <s.kerkmann@pengutronix.de>
Subject: [PATCH 1/2] of: fdt: fix memory leak in fdt_ensure_space
Date: Wed, 31 Jan 2024 17:56:59 +0100	[thread overview]
Message-ID: <20240131-fix-fdt-memory-safety-v1-1-3d3a2c797eec@pengutronix.de> (raw)
In-Reply-To: <20240131-fix-fdt-memory-safety-v1-0-3d3a2c797eec@pengutronix.de>

If the reallocation failed the old memory remains allocated and is never
freed, this is fixed by freeing the old memory on error.

Signed-off-by: Stefan Kerkmann <s.kerkmann@pengutronix.de>
---
 drivers/of/fdt.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 5c21bab5de..4f79a6120f 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -375,24 +375,37 @@ static void *memalign_realloc(void *orig, size_t oldsize, size_t newsize)
 
 static int fdt_ensure_space(struct fdt *fdt, int dtsize)
 {
+	size_t new_size;
+	void *previous;
+
 	/*
 	 * We assume strings and names have a maximum length of 1024
 	 * whereas properties can be longer. We allocate new memory
 	 * if we have less than 1024 bytes (+ the property size left.
 	 */
 	if (fdt->str_size - fdt->str_nextofs < 1024) {
-		fdt->strings = realloc(fdt->strings, fdt->str_size * 2);
-		if (!fdt->strings)
+		previous = fdt->strings;
+		new_size = fdt->str_size * 2;
+
+		if ((fdt->strings = realloc(previous, new_size)) == NULL) {
+			free(previous);
 			return -ENOMEM;
-		fdt->str_size *= 2;
+		}
+
+		fdt->str_size = new_size;
 	}
 
 	if (fdt->dt_size - fdt->dt_nextofs < 1024 + dtsize) {
-		fdt->dt = memalign_realloc(fdt->dt, fdt->dt_size,
-				fdt->dt_size * 2);
-		if (!fdt->dt)
+		previous = fdt->dt;
+		new_size = fdt->dt_size * 2;
+
+		if ((fdt->dt = memalign_realloc(previous, fdt->dt_size,
+						new_size)) == NULL) {
+			free(previous);
 			return -ENOMEM;
-		fdt->dt_size *= 2;
+		}
+
+		fdt->dt_size = new_size;
 	}
 
 	return 0;

-- 
2.39.2




  reply	other threads:[~2024-01-31 16:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-31 16:56 [PATCH 0/2] of: fdt: fix memory leak and oob writes " Stefan Kerkmann
2024-01-31 16:56 ` Stefan Kerkmann [this message]
2024-01-31 17:15   ` [PATCH 1/2] of: fdt: fix memory leak " Ahmad Fatoum
2024-02-01  8:34     ` Stefan Kerkmann
2024-01-31 16:57 ` [PATCH 2/2] of: fdt: fix oob writes with large ftd properties Stefan Kerkmann
2024-01-31 17:21   ` Ahmad Fatoum
2024-02-01 10:24     ` Stefan Kerkmann
2024-02-01 10:42       ` Ahmad Fatoum
2024-02-01  7:47   ` Sascha Hauer
2024-02-01  8:49     ` Stefan Kerkmann

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