All of lore.kernel.org
 help / color / mirror / Atom feed
From: Takashi Iwai <tiwai@suse.de>
To: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Subject: [PATCH] btrfs: sysfs: Use scnprintf() for avoiding potential buffer overflow
Date: Wed, 11 Mar 2020 10:33:23 +0100	[thread overview]
Message-ID: <20200311093323.24955-1-tiwai@suse.de> (raw)

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 fs/btrfs/sysfs.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 93cf76118a04..d3dc069789a5 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -310,12 +310,12 @@ static ssize_t supported_checksums_show(struct kobject *kobj,
 		 * This "trick" only works as long as 'enum btrfs_csum_type' has
 		 * no holes in it
 		 */
-		ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
+		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
 				(i == 0 ? "" : " "), btrfs_super_csum_name(i));
 
 	}
 
-	ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n");
+	ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
 	return ret;
 }
 BTRFS_ATTR(static_feature, supported_checksums, supported_checksums_show);
@@ -992,7 +992,7 @@ char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
 			continue;
 
 		name = btrfs_feature_attrs[set][i].kobj_attr.attr.name;
-		len += snprintf(str + len, bufsize - len, "%s%s",
+		len += scnprintf(str + len, bufsize - len, "%s%s",
 				len ? "," : "", name);
 	}
 
-- 
2.16.4


             reply	other threads:[~2020-03-11  9:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11  9:33 Takashi Iwai [this message]
2020-03-11 12:27 ` [PATCH] btrfs: sysfs: Use scnprintf() for avoiding potential buffer overflow Anand Jain
2020-03-11 19:10 ` David Sterba
2020-03-11 19:59   ` Takashi Iwai
2020-03-20 21:26     ` David Sterba
2020-03-20 22:45       ` Takashi Iwai

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=20200311093323.24955-1-tiwai@suse.de \
    --to=tiwai@suse.de \
    --cc=clm@fb.com \
    --cc=dsterba@suse.com \
    --cc=josef@toxicpanda.com \
    --cc=linux-btrfs@vger.kernel.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.