linux-kernel - [PATCH] Btrfs: avoid buffer overrun in btrfs

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Thu, 26 Apr 2012 18:35:12 +0200
From:	Jim Meyering <jim@...ering.net>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:	Josef Bacik <josef@...hat.com>
Subject: [PATCH] Btrfs: avoid buffer overrun in btrfs_printk


The buffer read-overrun would be triggered by a printk format
starting with <N>, where N is a single digit.  NUL-terminate
after strncpy.  Use memcpy, not strncpy, since we know the
string we're copying fits in the destination buffer and
contains no NUL byte.

Signed-off-by: Jim Meyering <meyering@...hat.com>
---
 fs/btrfs/super.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 5ddf172..626f574 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -180,23 +180,24 @@ const char *logtypes[] = {
 void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...)
 {
 	struct super_block *sb = fs_info->sb;
 	char lvl[4];
 	struct va_format vaf;
 	va_list args;
 	const char *type = logtypes[4];

 	va_start(args, fmt);

 	if (fmt[0] == '<' && isdigit(fmt[1]) && fmt[2] == '>') {
-		strncpy(lvl, fmt, 3);
+		memcpy(lvl, fmt, 3);
+		lvl[3] = '\0';
 		fmt += 3;
 		type = logtypes[fmt[1] - '0'];
 	} else
 		*lvl = '\0';

 	vaf.fmt = fmt;
 	vaf.va = &args;
 	printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf);
 }

 /*
--
1.7.10.336.gc5e31
--
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/