On 4/27/23 05:08, Zheng Wang wrote:
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.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
applied.
Thanks!
Helge
---
v2:
- add return error code in another location.
---
drivers/video/fbdev/imsttfb.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/video/fbdev/imsttfb.c b/drivers/video/fbdev/imsttfb.c
index bea45647184e..975dd682fae4 100644
--- a/drivers/video/fbdev/imsttfb.c
+++ b/drivers/video/fbdev/imsttfb.c
@@ -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)
