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net: mvneta: Fix an out of bounds check

PATCH Applied Dan Carpenter 3 participants 3 messages Dec 7, 2022 – Dec 8, 2022

Subsystems (4)
Networking Network drivers Kernel janitors Marvell mvneta Ethernet driver
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Dan Carpenter

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#0 lore raw

PATCH v2 1/1 net: mvneta: Fix an out of bounds check

In an earlier commit, I added a bounds check to prevent an out of bounds read and a WARN(). On further discussion and consideration that check was probably too aggressive. Instead of returning -EINVAL, a better fix would be to just prevent the out of bounds read but continue the process.

Background: The value of "pp->rxq_def" is a number between 0-7 by default, or even higher depending on the value of "rxq_number", which is a module parameter. If the value is more than the number of available CPUs then it will trigger the WARN() in cpu_max_bits_warn().

Fixes e8b4fc13900b ("net: mvneta: Prevent out of bounds read in mvneta_config_rss()")
Signed-off-by Dan Carpenter <[email protected]>

---
v2: fix the subject to say net instead of net-next.

 drivers/net/ethernet/marvell/mvneta.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
drivers/net/ethernet/marvell/mvneta.c +1 -4
index 66b7f27c9a48..5aefaaff0871 100644
@@ -4271,7 +4271,7 @@ static void mvneta_percpu_elect(struct mvneta_port *pp)
 	/* Use the cpu associated to the rxq when it is online, in all
 	 * the other cases, use the cpu 0 which can't be offline.
 	 */
-	if (cpu_online(pp->rxq_def))
+	if (pp->rxq_def < nr_cpu_ids && cpu_online(pp->rxq_def))
 		elected_cpu = pp->rxq_def;
 
 	max_cpu = num_present_cpus();

@@ -4927,9 +4927,6 @@ static int  mvneta_config_rss(struct mvneta_port *pp)
 		napi_disable(&pp->napi);
 	}
 
-	if (pp->indir[0] >= nr_cpu_ids)
-		return -EINVAL;
-
 	pp->rxq_def = pp->indir[0];
 
 	/* Update unicast mapping */
Signature · 1 line
2.35.1
Reviewed-by on v2 1/1
#1 lore raw
Quoted 10 lines · Dan Carpenter

In an earlier commit, I added a bounds check to prevent an out of bounds read and a WARN(). On further discussion and consideration that check was probably too aggressive. Instead of returning -EINVAL, a better fix would be to just prevent the out of bounds read but continue the process.

Background: The value of "pp->rxq_def" is a number between 0-7 by default, or even higher depending on the value of "rxq_number", which is a module parameter. If the value is more than the number of available CPUs then it will trigger the WARN() in cpu_max_bits_warn().

Quoted 8 lines
Fixes e8b4fc13900b ("net: mvneta: Prevent out of bounds read in mvneta_config_rss()")
Signed-off-by Dan Carpenter <[email protected]>

---
v2: fix the subject to say net instead of net-next.

 drivers/net/ethernet/marvell/mvneta.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

Thanks for the followup,

Reviewed-by Leon Romanovsky <[email protected]>
CI Applied
#2 lore raw
In reply to Dan Carpenter
This patch was applied to netdev/net.git (master) by Jakub Kicinski <[email protected]>:

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <[email protected]>:

Quoted 11 lines · On Wed, 7 Dec 2022 10:06:31 +0300 you wrote:

In an earlier commit, I added a bounds check to prevent an out of bounds read and a WARN(). On further discussion and consideration that check was probably too aggressive. Instead of returning -EINVAL, a better fix would be to just prevent the out of bounds read but continue the process.

Background: The value of "pp->rxq_def" is a number between 0-7 by default, or even higher depending on the value of "rxq_number", which is a module parameter. If the value is more than the number of available CPUs then it will trigger the WARN() in cpu_max_bits_warn().

[...]

Here is the summary with links:
- [net,v2] net: mvneta: Fix an out of bounds check

    https://git.kernel.org/netdev/net/c/cdd97383e19d

You are awesome, thank you!

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