From: Nicholas Mc Guire <hofrat@osadl.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jessica Yu <jeyu@kernel.org>, Jiri Kosina <jikos@kernel.org>,
Miroslav Benes <mbenes@suse.cz>, Petr Mladek <pmladek@suse.com>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Nicholas Mc Guire <hofrat@osadl.org>
Subject: [PATCH 2/2] livepatch: check kzalloc return values
Date: Fri, 14 Dec 2018 17:56:10 +0100 [thread overview]
Message-ID: <1544806570-21299-2-git-send-email-hofrat@osadl.org> (raw)
In-Reply-To: <1544806570-21299-1-git-send-email-hofrat@osadl.org>
kzalloc() return should always be checked - notably in example code
where this may be seen as reference. On failure of allocation in
livepatch_fix1_dummy_alloc() respectively dummy_alloc() previous
allocation is freed (thanks to Petr Mladek <pmladek@suse.com> for
catching this) and NULL returned.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Fixes: 439e7271dc2b ("livepatch: introduce shadow variable API")
---
Problem located with an experimental coccinelle script
Patch was compile tested with: x86_64_defconfig + FTRACE=y
FUNCTION_TRACER=y, EXPERT=y, LATENCYTOP=y, SAMPLES=y,
SAMPLE_LIVEPATCH=y
Patch is against 4.20-rc6 (localversion-next is next-20181214)
on top of 0001-livepatch-fix-non-static-warnings.patch
samples/livepatch/livepatch-shadow-fix1.c | 5 +++++
samples/livepatch/livepatch-shadow-mod.c | 4 ++++
2 files changed, 9 insertions(+)
diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c
index eaab10f..1974eb5 100644
--- a/samples/livepatch/livepatch-shadow-fix1.c
+++ b/samples/livepatch/livepatch-shadow-fix1.c
@@ -89,6 +89,11 @@ static __noclone struct dummy *livepatch_fix1_dummy_alloc(void)
* pointer to handle resource release.
*/
leak = kzalloc(sizeof(int), GFP_KERNEL);
+ if (!leak) {
+ kfree(d);
+ return NULL;
+ }
+
klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
shadow_leak_ctor, leak);
diff --git a/samples/livepatch/livepatch-shadow-mod.c b/samples/livepatch/livepatch-shadow-mod.c
index dc69da0..b4ece36 100644
--- a/samples/livepatch/livepatch-shadow-mod.c
+++ b/samples/livepatch/livepatch-shadow-mod.c
@@ -123,6 +123,10 @@ static __noclone noinline struct dummy *dummy_alloc(void)
/* Oops, forgot to save leak! */
leak = kzalloc(sizeof(int), GFP_KERNEL);
+ if (!leak) {
+ kfree(d);
+ return NULL;
+ }
pr_info("%s: dummy @ %p, expires @ %lx\n",
__func__, d, d->jiffies_expire);
--
2.1.4
next prev parent reply other threads:[~2018-12-14 16:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-14 16:56 [PATCH 1/2] livepatch: fix non-static warnings Nicholas Mc Guire
2018-12-14 16:56 ` Nicholas Mc Guire [this message]
2018-12-14 21:39 ` [PATCH 2/2] livepatch: check kzalloc return values Joe Lawrence
2018-12-17 11:41 ` Petr Mladek
2018-12-17 11:43 ` Miroslav Benes
2018-12-18 9:23 ` Jiri Kosina
2018-12-14 21:34 ` [PATCH 1/2] livepatch: fix non-static warnings Joe Lawrence
2018-12-14 21:51 ` Josh Poimboeuf
2018-12-14 22:03 ` Joe Lawrence
2018-12-15 8:50 ` Nicholas Mc Guire
2018-12-15 16:23 ` Joe Lawrence
2018-12-17 11:49 ` Petr Mladek
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=1544806570-21299-2-git-send-email-hofrat@osadl.org \
--to=hofrat@osadl.org \
--cc=jeyu@kernel.org \
--cc=jikos@kernel.org \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=live-patching@vger.kernel.org \
--cc=mbenes@suse.cz \
--cc=pmladek@suse.com \
/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).