From b6e4e0a83b78bc98446e2041efc50ddb81e44cb2 Mon Sep 17 00:00:00 2001 From: Igor Matheus Andrade Torrente Date: Mon, 3 May 2021 13:57:06 +0200 Subject: [PATCH] video: hgafb: fix potential NULL pointer dereference commit dc13cac4862cc68ec74348a80b6942532b7735fa upstream. The return of ioremap if not checked, and can lead to a NULL to be assigned to hga_vram. Potentially leading to a NULL pointer dereference. The fix adds code to deal with this case in the error label and changes how the hgafb_probe handles the return of hga_card_detect. Cc: Ferenc Bakonyi Cc: Bartlomiej Zolnierkiewicz Cc: stable Signed-off-by: Igor Matheus Andrade Torrente Link: https://lore.kernel.org/r/20210503115736.2104747-40-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/hgafb.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c index 463028543173..b2b996196132 100644 --- a/drivers/video/fbdev/hgafb.c +++ b/drivers/video/fbdev/hgafb.c @@ -285,6 +285,8 @@ static int hga_card_detect(void) hga_vram_len = 0x08000; hga_vram = ioremap(0xb0000, hga_vram_len); + if (!hga_vram) + return -ENOMEM; if (request_region(0x3b0, 12, "hgafb")) release_io_ports = 1; @@ -344,13 +346,18 @@ static int hga_card_detect(void) hga_type_name = "Hercules"; break; } - return 1; + return 0; error: if (release_io_ports) release_region(0x3b0, 12); if (release_io_port) release_region(0x3bf, 1); - return 0; + + iounmap(hga_vram); + + pr_err("hgafb: HGA card not detected.\n"); + + return -EINVAL; } /** @@ -548,13 +555,11 @@ static struct fb_ops hgafb_ops = { static int hgafb_probe(struct platform_device *pdev) { struct fb_info *info; + int ret; - if (! hga_card_detect()) { - printk(KERN_INFO "hgafb: HGA card not detected.\n"); - if (hga_vram) - iounmap(hga_vram); - return -EINVAL; - } + ret = hga_card_detect(); + if (!ret) + return ret; printk(KERN_INFO "hgafb: %s with %ldK of memory detected.\n", hga_type_name, hga_vram_len/1024); -- 2.20.1