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* [PATCH] memory: gpmc: fix out of bounds read and dereference on gpmc_cs[]
@ 2021-02-23 19:38 Colin King
  2021-02-23 19:52 ` Krzysztof Kozlowski
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Colin King @ 2021-02-23 19:38 UTC (permalink / raw)
  To: Roger Quadros, Tony Lindgren, Krzysztof Kozlowski, linux-omap
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

Currently the array gpmc_cs is indexed by cs before it cs is range checked
and the pointer read from this out-of-index read is dereferenced. Fix this
by performing the range check on cs before the read and the following
pointer dereference.

Addresses-Coverity: ("Negative array index read")
Fixes: 186401937927 ("memory: gpmc: Move omap gpmc code to live under drivers")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/memory/omap-gpmc.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
index cfa730cfd145..f80c2ea39ca4 100644
--- a/drivers/memory/omap-gpmc.c
+++ b/drivers/memory/omap-gpmc.c
@@ -1009,8 +1009,8 @@ EXPORT_SYMBOL(gpmc_cs_request);
 
 void gpmc_cs_free(int cs)
 {
-	struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
-	struct resource *res = &gpmc->mem;
+	struct gpmc_cs_data *gpmc;
+	struct resource *res;
 
 	spin_lock(&gpmc_mem_lock);
 	if (cs >= gpmc_cs_num || cs < 0 || !gpmc_cs_reserved(cs)) {
@@ -1018,6 +1018,9 @@ void gpmc_cs_free(int cs)
 		spin_unlock(&gpmc_mem_lock);
 		return;
 	}
+	gpmc = &gpmc_cs[cs];
+	res = &gpmc->mem;
+
 	gpmc_cs_disable_mem(cs);
 	if (res->flags)
 		release_resource(res);
-- 
2.30.0


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2021-03-03  1:01 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-23 19:38 [PATCH] memory: gpmc: fix out of bounds read and dereference on gpmc_cs[] Colin King
2021-02-23 19:52 ` Krzysztof Kozlowski
2021-02-24  7:55 ` Dan Carpenter
2021-02-24  8:11   ` Krzysztof Kozlowski
2021-02-25 12:37     ` Tony Lindgren
2021-02-24  8:46   ` Colin Ian King
2021-03-02  8:44 ` Krzysztof Kozlowski
2021-03-02  8:54   ` Colin Ian King

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