linux-kernel - [PATCH 2/2] perf tools: Fix strbuf_addf() when the buffer needs to grow

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 23 Oct 2012 22:44:50 +0900
From:	Namhyung Kim <namhyung@...nel.org>
To:	Andrew Jones <drjones@...hat.com>
Cc:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] perf tools: Fix strbuf_addf() when the buffer needs to grow

This was found during chasing down the header output regression.
The strbuf_addf() was checking buffer length with a result of
vscnprintf() which cannot be greater than that of strbuf_avail().

Since numa topology and pmu mapping info in header were converted
to use strbuf, it sometimes caused uninteresting behaviors with the
broken strbuf.

Fix it by using vsnprintf() which returns desired output string
length regardless of the available buffer size and grow the buffer
if needed.

Reported-by: Andrew Jones <drjones@...hat.com>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
 tools/perf/util/strbuf.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/strbuf.c b/tools/perf/util/strbuf.c
index 2eeb51baf077..cfa906882e2c 100644
--- a/tools/perf/util/strbuf.c
+++ b/tools/perf/util/strbuf.c
@@ -90,17 +90,17 @@ void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
 	if (!strbuf_avail(sb))
 		strbuf_grow(sb, 64);
 	va_start(ap, fmt);
-	len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 	va_end(ap);
 	if (len < 0)
-		die("your vscnprintf is broken");
+		die("your vsnprintf is broken");
 	if (len > strbuf_avail(sb)) {
 		strbuf_grow(sb, len);
 		va_start(ap, fmt);
-		len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 		va_end(ap);
 		if (len > strbuf_avail(sb)) {
-			die("this should not happen, your snprintf is broken");
+			die("this should not happen, your vsnprintf is broken");
 		}
 	}
 	strbuf_setlen(sb, sb->len + len);
-- 
1.7.9.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/