From: Zheyu Ma <zheyuma97@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
security@kernel.org, Zheyu Ma <zheyuma97@gmail.com>
Subject: [PATCH] video: fbdev: kyrofb: fix a DoS bug by restricting user input
Date: Tue, 13 Jul 2021 12:51:14 +0000 [thread overview]
Message-ID: <1626180674-25195-1-git-send-email-zheyuma97@gmail.com> (raw)
The user can pass in any value to the driver through the 'ioctl'
interface. The driver dost not check, which may cause DoS bugs.
Fix this by checking if the divisor is 0
The following log reveals it:
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:SetOverlayViewPort+0x133/0x5f0 drivers/video/fbdev/kyro/STG4000OverlayDevice.c:476
Call Trace:
kyro_dev_overlay_viewport_set drivers/video/fbdev/kyro/fbdev.c:378 [inline]
kyrofb_ioctl+0x2eb/0x330 drivers/video/fbdev/kyro/fbdev.c:603
do_fb_ioctl+0x1f3/0x700 drivers/video/fbdev/core/fbmem.c:1171
fb_ioctl+0xeb/0x130 drivers/video/fbdev/core/fbmem.c:1185
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x19b/0x220 fs/ioctl.c:739
do_syscall_64+0x32/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
drivers/video/fbdev/kyro/STG4000OverlayDevice.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/video/fbdev/kyro/STG4000OverlayDevice.c b/drivers/video/fbdev/kyro/STG4000OverlayDevice.c
index 9fde0e3b69ec..29d692fe5e75 100644
--- a/drivers/video/fbdev/kyro/STG4000OverlayDevice.c
+++ b/drivers/video/fbdev/kyro/STG4000OverlayDevice.c
@@ -407,6 +407,9 @@ int SetOverlayViewPort(volatile STG4000REG __iomem *pSTGReg,
ulVertDecFactor = 1;
}
+ if ((ulDest + 1) == 0)
+ return -EINVAL;
+
ulDacYScale = ((ulSrc - 1) * 2048) / (ulDest + 1);
tmp = STG_READ_REG(DACOverlayVtDec); /* Decimation */
@@ -471,6 +474,9 @@ int SetOverlayViewPort(volatile STG4000REG __iomem *pSTGReg,
*/
ulScaleLeft = ulSrcLeft;
+ if ((ulRight - ulLeft + 2) == 0)
+ return -EINVAL;
+
/* shift fxscale until it is in the range of the scaler */
ulhDecim = 0;
ulScale = (((ulSrcRight - ulSrcLeft) - 1) << (11 - ulhDecim)) / (ulRight - ulLeft + 2);
--
2.17.6
reply other threads:[~2021-07-13 12:51 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1626180674-25195-1-git-send-email-zheyuma97@gmail.com \
--to=zheyuma97@gmail.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=linux-fbdev@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=security@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).