[PATCH 3.16 310/370] lib/vsprintf.c: improve sanity check in vsnprintf()

From	Ben Hutchings <ben@decadent.org.uk>
Newsgroups	linux.kernel
Subject	[PATCH 3.16 310/370] lib/vsprintf.c: improve sanity check in vsnprintf()
Date	2017-03-10 14:40 +0100
Message-ID	<tjsW0-4FY-77@gated-at.bofh.it> (permalink)
References	<tjrnb-3sF-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

3.16.42-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Rasmus Villemoes <linux@rasmusvillemoes.dk>

commit 2aa2f9e21e4eb25c720b2e7d80f8929638f6ad73 upstream.

On 64 bit, size may very well be huge even if bit 31 happens to be 0.
Somehow it doesn't feel right that one can pass a 5 GiB buffer but not a
3 GiB one.  So cap at INT_MAX as was probably the intention all along.
This is also the made-up value passed by sprintf and vsprintf.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Willy Tarreau <w@1wt.eu>
---
 lib/vsprintf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1657,7 +1657,7 @@ int vsnprintf(char *buf, size_t size, co
 
 	/* Reject out-of-range values early.  Large positive sizes are
 	   used for unknown buffer sizes. */
-	if (WARN_ON_ONCE((int) size < 0))
+	if (WARN_ON_ONCE(size > INT_MAX))
 		return 0;
 
 	str = buf;

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

[PATCH 3.16 310/370] lib/vsprintf.c: improve sanity check in  vsnprintf() Ben Hutchings <ben@decadent.org.uk> - 2017-03-10 14:40 +0100

csiph-web