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fbdev: imsttfb: Fix use after free bug in imsttfb_probe

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commit c75f5a5506 upstream.

A use-after-free bug may occur if init_imstt invokes framebuffer_release
and free the info ptr. The caller, imsttfb_probe didn't notice that and
still keep the ptr as private data in pdev.

If we remove the driver which will call imsttfb_remove to make cleanup,
UAF happens.

Fix it by return error code if bad case happens in init_imstt.

Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Zheng Wang 2023-04-27 11:08:41 +08:00 committed by Greg Kroah-Hartman
parent 9559a3e60c
commit 64c6b84c73
1 changed files with 10 additions and 8 deletions
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18
drivers/video/fbdev/imsttfb.c
View file

@ -1348,7 +1348,7 @@ static struct fb_ops imsttfb_ops = {
.fb_ioctl = imsttfb_ioctl,
};
static void init_imstt(struct fb_info *info)
static int init_imstt(struct fb_info *info)
{
struct imstt_par *par = info->par;
__u32 i, tmp, *ip, *end;
@ -1420,7 +1420,7 @@ static void init_imstt(struct fb_info *info)
|| !(compute_imstt_regvals(par, info->var.xres, info->var.yres))) {
printk("imsttfb: %ux%ux%u not supported\n", info->var.xres, info->var.yres, info->var.bits_per_pixel);
framebuffer_release(info);
return;
return -ENODEV;
}
sprintf(info->fix.id, "IMS TT (%s)", par->ramdac == IBM ? "IBM" : "TVP");
@ -1460,12 +1460,13 @@ static void init_imstt(struct fb_info *info)
if (register_framebuffer(info) < 0) {
fb_dealloc_cmap(&info->cmap);
framebuffer_release(info);
return;
return -ENODEV;
}
tmp = (read_reg_le32(par->dc_regs, SSTATUS) & 0x0f00) >> 8;
fb_info(info, "%s frame buffer; %uMB vram; chip version %u\n",
info->fix.id, info->fix.smem_len >> 20, tmp);
return 0;
}
static int imsttfb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
@ -1474,7 +1475,8 @@ static int imsttfb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
struct imstt_par *par;
struct fb_info *info;
struct device_node *dp;
int ret;
dp = pci_device_to_OF_node(pdev);
if(dp)
printk(KERN_INFO "%s: OF name %s\n",__func__, dp->name);
@ -1525,10 +1527,10 @@ static int imsttfb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
par->cmap_regs_phys = addr + 0x840000;
par->cmap_regs = (__u8 *)ioremap(addr + 0x840000, 0x1000);
info->pseudo_palette = par->palette;
init_imstt(info);
pci_set_drvdata(pdev, info);
return 0;
ret = init_imstt(info);
if (!ret)
pci_set_drvdata(pdev, info);
return ret;
}
static void imsttfb_remove(struct pci_dev *pdev)