linux-kernel - [PATCH] video: fbdev: sis: fix potential NULL dereference in sisfb_post

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Message-ID: <1648784476-20803-1-git-send-email-baihaowen@meizu.com>
Date:   Fri, 1 Apr 2022 11:41:16 +0800
From:   Haowen Bai <baihaowen@...zu.com>
To:     Thomas Winischhofer <thomas@...ischhofer.net>,
        Helge Deller <deller@....de>
CC:     Haowen Bai <baihaowen@...zu.com>, <linux-fbdev@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] video: fbdev: sis: fix potential NULL dereference in sisfb_post_sis300()

bios could be null without checking null and return in this function,
but still dereference bios[0xf5].

Signed-off-by: Haowen Bai <baihaowen@...zu.com>
---
 drivers/video/fbdev/sis/sis_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/sis/sis_main.c b/drivers/video/fbdev/sis/sis_main.c
index 742f629..24a0299 100644
--- a/drivers/video/fbdev/sis/sis_main.c
+++ b/drivers/video/fbdev/sis/sis_main.c
@@ -4463,7 +4463,7 @@ static void sisfb_post_sis300(struct pci_dev *pdev)
 		SiS_SetReg(SISCR, 0x37, 0x02);
 		SiS_SetReg(SISPART2, 0x00, 0x1c);
 		v4 = 0x00; v5 = 0x00; v6 = 0x10;
-		if(ivideo->SiS_Pr.UseROM) {
+		if (ivideo->SiS_Pr.UseROM && bios) {
 			v4 = bios[0xf5];
 			v5 = bios[0xf6];
 			v6 = bios[0xf7];
-- 
2.7.4