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Message-Id: <20230520182215.845131-7-sashal@kernel.org>
Date: Sat, 20 May 2023 14:22:10 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Zheng Wang <zyytlz.wz@....com>, Helge Deller <deller@....de>,
Sasha Levin <sashal@...nel.org>, tzimmermann@...e.de,
javierm@...hat.com, linux-fbdev@...r.kernel.org,
dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.15 07/11] fbdev: imsttfb: Fix use after free bug in imsttfb_probe
From: Zheng Wang <zyytlz.wz@....com>
[ 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@....com>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
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 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)
--
2.39.2
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