[PATCH 39/69] video: hgafb: fix potential NULL pointer dereference
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-05-03 12:03:27
Also in:
lkml
Subsystem:
framebuffer layer, the rest · Maintainers:
Helge Deller, Linus Torvalds
From: Igor Matheus Andrade Torrente <redacted> 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 <redacted> Cc: Bartlomiej Zolnierkiewicz <redacted> Cc: stable <redacted> Signed-off-by: Igor Matheus Andrade Torrente <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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 fca29f219f8b..cc8e62ae93f6 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 const 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);
--
2.31.1