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fbdev: imsttfb: Fix use after free bug in imsttfb_probe

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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>
This commit is contained in:
Zheng Wang 2023-04-27 11:08:41 +08:00 committed by Helge Deller
parent 6208890495
commit c75f5a5506
1 changed files with 8 additions and 7 deletions
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15
drivers/video/fbdev/imsttfb.c
View File

@ -1347,7 +1347,7 @@ static const 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");
@ -1456,12 +1456,13 @@ static void init_imstt(struct fb_info *info)
if (register_framebuffer(info) < 0) {
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)
@ -1529,10 +1530,10 @@ static int imsttfb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
if (!par->cmap_regs)
goto error;
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;
error:
if (par->dc_regs)