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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Zhou Qingyang <zhou1615@umn.edu>,
        Lyude Paul <lyude@redhat.com>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0428/1017] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()
Date:   Tue,  5 Apr 2022 09:22:21 +0200
Message-Id: <20220405070406.997309903@linuxfoundation.org>
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From: Zhou Qingyang <zhou1615@umn.edu>

[ Upstream commit 2343bcdb4747d4f418a4daf2e898b94f86c24a59 ]

In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
passed to memcpy(), which could lead to undefined behavior on failure
of kmalloc().

Fix this bug by using kmemdup() instead of kmalloc()+memcpy().

This bug was found by a static analyzer.

Builds with 'make allyesconfig' show no new warnings,
and our static analyzer no longer warns about this code.

Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace "secure boot"")
Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220124165856.57022-1-zhou1615@umn.edu
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
index 667fa016496e..a6ea89a5d51a 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
@@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const char *name, int ver,
 
 	hsfw->imem_size = desc->code_size;
 	hsfw->imem_tag = desc->start_tag;
-	hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
-	memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
-
+	hsfw->imem = kmemdup(data + desc->code_off, desc->code_size, GFP_KERNEL);
 	nvkm_firmware_put(fw);
-	return 0;
+	if (!hsfw->imem)
+		return -ENOMEM;
+	else
+		return 0;
 }
 
 int
-- 
2.34.1