This is a note to let you know that I've just added the patch titled
fbdev: imsttfb: Fix use after free bug in imsttfb_probe
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fbdev-imsttfb-fix-use-after-free-bug-in-imsttfb_prob.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4609bac23b3efd08c3016349ee07cf8dc8ed2b07
Author: Zheng Wang <zyytlz.wz@xxxxxxx>
Date: Thu Apr 27 11:08:41 2023 +0800
fbdev: imsttfb: Fix use after free bug in imsttfb_probe
[ Upstream commit c75f5a55061091030a13fef71b9995b89bc86213 ]
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@xxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/video/fbdev/imsttfb.c b/drivers/video/fbdev/imsttfb.c
index 16f272a508112..1b2fb8ed76237 100644
--- a/drivers/video/fbdev/imsttfb.c
+++ b/drivers/video/fbdev/imsttfb.c
@@ -1346,7 +1346,7 @@ 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;
@@ -1419,7 +1419,7 @@ 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");
@@ -1455,12 +1455,13 @@ 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)
@@ -1523,10 +1524,10 @@ 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)
