linux-fbdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Pavel Skripkin <paskripkin@gmail.com>
To: gustavoars@kernel.org, sam@ravnborg.org, tomi.valkeinen@ti.com
Cc: linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	Pavel Skripkin <paskripkin@gmail.com>
Subject: [PATCH] OMAP: DSS2: OMAPFB: fix potential GPF
Date: Sat, 26 Jun 2021 01:33:23 +0300	[thread overview]
Message-ID: <20210625223323.13930-1-paskripkin@gmail.com> (raw)

In case of allocation failures, all code paths was jumping
to this code:

err:
	kfree(fbi);
	kfree(var);
	kfree(fbops);

	return r;

Since all 3 pointers placed on stack and don't initialized, they
will be filled with some random values, which leads to
deferencing random pointers in kfree(). Fix it by rewriting
error handling path.

Fixes: 897044e99e43 ("OMAP: DSS2: OMAPFB: Reduce stack usage")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 .../video/fbdev/omap2/omapfb/omapfb-main.c    | 21 +++++++++----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/video/fbdev/omap2/omapfb/omapfb-main.c b/drivers/video/fbdev/omap2/omapfb/omapfb-main.c
index a3decc7fadde..6a302138ebeb 100644
--- a/drivers/video/fbdev/omap2/omapfb/omapfb-main.c
+++ b/drivers/video/fbdev/omap2/omapfb/omapfb-main.c
@@ -2025,21 +2025,19 @@ static int omapfb_mode_to_timings(const char *mode_str,
 	fbops = NULL;
 
 	fbi = kzalloc(sizeof(*fbi), GFP_KERNEL);
-	if (fbi == NULL) {
-		r = -ENOMEM;
-		goto err;
-	}
+	if (fbi == NULL)
+		return -ENOMEM;
 
 	var = kzalloc(sizeof(*var), GFP_KERNEL);
 	if (var == NULL) {
 		r = -ENOMEM;
-		goto err;
+		goto err_var;
 	}
 
 	fbops = kzalloc(sizeof(*fbops), GFP_KERNEL);
 	if (fbops == NULL) {
 		r = -ENOMEM;
-		goto err;
+		goto err_fbops;
 	}
 
 	fbi->fbops = fbops;
@@ -2047,7 +2045,7 @@ static int omapfb_mode_to_timings(const char *mode_str,
 	r = fb_find_mode(var, fbi, mode_str, NULL, 0, NULL, 24);
 	if (r == 0) {
 		r = -EINVAL;
-		goto err;
+		goto err_find;
 	}
 
 	if (display->driver->get_timings) {
@@ -2088,11 +2086,12 @@ static int omapfb_mode_to_timings(const char *mode_str,
 
 	r = 0;
 
-err:
-	kfree(fbi);
-	kfree(var);
+err_find:
 	kfree(fbops);
-
+err_fbops:
+	kfree(var);
+err_var:
+	kfree(fbi);
 	return r;
 }
 
-- 
2.32.0


             reply	other threads:[~2021-06-25 22:33 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-25 22:33 Pavel Skripkin [this message]
2021-06-26 23:14 ` Aaro Koskinen
2021-06-27  8:48   ` Pavel Skripkin

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=20210625223323.13930-1-paskripkin@gmail.com \
    --to=paskripkin@gmail.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=gustavoars@kernel.org \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=linux-kernel-mentees@lists.linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-omap@vger.kernel.org \
    --cc=sam@ravnborg.org \
    --cc=tomi.valkeinen@ti.com \
    --subject='Re: [PATCH] OMAP: DSS2: OMAPFB: fix potential GPF' \
    /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

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).