From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Fam Zheng" <fam@euphon.net>,
"Peter Maydell" <peter.maydell@linaro.org>,
kvm@vger.kernel.org, "David Hildenbrand" <david@redhat.com>,
"Jason Wang" <jasowang@redhat.com>,
"Mark Cave-Ayland" <mark.cave-ayland@ilande.co.uk>,
"Michael Roth" <mdroth@linux.vnet.ibm.com>,
"Gerd Hoffmann" <kraxel@redhat.com>,
"Eric Blake" <eblake@redhat.com>,
"Liam Merwick" <liam.merwick@oracle.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
xen-devel@lists.xenproject.org, qemu-block@nongnu.org,
"Juan Quintela" <quintela@redhat.com>,
"Aleksandar Rikalo" <arikalo@wavecomp.com>,
"Helge Deller" <deller@gmx.de>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>,
"Halil Pasic" <pasic@linux.ibm.com>,
"Christian Borntraeger" <borntraeger@de.ibm.com>,
"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
"Anthony Perard" <anthony.perard@citrix.com>,
"Marc-André Lureau" <marcandre.lureau@redh>
Subject: [PULL 1/7] trace: handle tracefs path truncation
Date: Mon, 25 Mar 2019 15:58:51 +0000 [thread overview]
Message-ID: <20190325155857.10661-2-stefanha@redhat.com> (raw)
In-Reply-To: <20190325155857.10661-1-stefanha@redhat.com>
If the tracefs mountpoint has a very long path we may exceed PATH_MAX.
This is a system misconfiguration and the user must resolve it so that
applications can perform path-based system calls successfully.
This issue does not occur on real-world systems since tracefs is mounted
on /sys/kernel/debug/tracing/, but the compiler is smart enough to
foresee the possibility and warn about the unchecked snprintf(3) return
value. This patch fixes the compiler warning.
Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Message-id: 20190321170831.6539-2-stefanha@redhat.com
Message-Id: <20190321170831.6539-2-stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
trace/ftrace.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/trace/ftrace.c b/trace/ftrace.c
index 61692a8682..9749543d9b 100644
--- a/trace/ftrace.c
+++ b/trace/ftrace.c
@@ -53,7 +53,11 @@ bool ftrace_init(void)
}
if (tracefs_found) {
- snprintf(path, PATH_MAX, "%s%s/tracing_on", mount_point, subdir);
+ if (snprintf(path, PATH_MAX, "%s%s/tracing_on", mount_point, subdir)
+ >= sizeof(path)) {
+ fprintf(stderr, "Using tracefs mountpoint would exceed PATH_MAX\n");
+ return false;
+ }
trace_fd = open(path, O_WRONLY);
if (trace_fd < 0) {
if (errno == EACCES) {
@@ -72,7 +76,11 @@ bool ftrace_init(void)
}
close(trace_fd);
}
- snprintf(path, PATH_MAX, "%s%s/trace_marker", mount_point, subdir);
+ if (snprintf(path, PATH_MAX, "%s%s/trace_marker", mount_point, subdir)
+ >= sizeof(path)) {
+ fprintf(stderr, "Using tracefs mountpoint would exceed PATH_MAX\n");
+ return false;
+ }
trace_marker_fd = open(path, O_WRONLY);
if (trace_marker_fd < 0) {
perror("Could not open ftrace 'trace_marker' file");
--
2.20.1
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next prev parent reply other threads:[~2019-03-25 15:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-25 15:58 [PULL 0/7] Tracing patches Stefan Hajnoczi
2019-03-25 15:58 ` Stefan Hajnoczi [this message]
2019-03-25 15:58 ` [PULL 2/7] trace: avoid SystemTap dtrace(1) warnings on empty files Stefan Hajnoczi
2019-03-25 15:58 ` [PULL 3/7] trace-events: Consistently point to docs/devel/tracing.txt Stefan Hajnoczi
2019-03-25 15:58 ` [PULL 4/7] trace-events: Shorten file names in comments Stefan Hajnoczi
2019-03-25 15:58 ` [PULL 5/7] scripts/cleanup-trace-events: Update for current practice Stefan Hajnoczi
2019-03-25 15:58 ` [PULL 6/7] trace-events: Delete unused trace points Stefan Hajnoczi
2019-03-25 15:58 ` [PULL 7/7] trace-events: Fix attribution of trace points to source Stefan Hajnoczi
2019-03-25 18:09 ` [PULL 0/7] Tracing patches Peter Maydell
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