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ocfs2: fix snprintf() checking 

[ Upstream commit 54e948c60cc843b6e84dc44496edc91f51d2a28e ]

The snprintf() function returns the number of bytes which would have been
printed if the buffer was large enough.  In other words it can return ">=
remain" but this code assumes it returns "== remain".

The run time impact of this bug is not very severe.  The next iteration
through the loop would trigger a WARN() when we pass a negative limit to
snprintf().  We would then return success instead of -E2BIG.

The kernel implementation of snprintf() will never return negatives so
there is no need to check and I have deleted that dead code.

Link: https://lkml.kernel.org/r/20210511135350.GV1955@kadam
Fixes: a860f6eb4c ("ocfs2: sysfile interfaces for online file check")
Fixes: 74ae4e104d ("ocfs2: Create stack glue sysfs files.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Dan Carpenter 2021-06-28 19:34:01 -07:00 committed by Greg Kroah-Hartman
parent 27d02a4d9d
commit 6ea84116b3
2 changed files with 3 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/ocfs2/filecheck.c
View File

@ -328,11 +328,7 @@ static ssize_t ocfs2_filecheck_attr_show(struct kobject *kobj,
ret = snprintf(buf + total, remain, "%lu\t\t%u\t%s\n",
p->fe_ino, p->fe_done,
ocfs2_filecheck_error(p->fe_status));
if (ret < 0) {
total = ret;
break;
}
if (ret == remain) {
if (ret >= remain) {
/* snprintf() didn't fit */
total = -E2BIG;
break;

8
fs/ocfs2/stackglue.c
View File

@ -502,11 +502,7 @@ static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
ret = snprintf(buf, remain, "%s\n",
p->sp_name);
if (ret < 0) {
total = ret;
break;
}
if (ret == remain) {
if (ret >= remain) {
/* snprintf() didn't fit */
total = -E2BIG;
break;
@ -533,7 +529,7 @@ static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
if (active_stack) {
ret = snprintf(buf, PAGE_SIZE, "%s\n",
active_stack->sp_name);
if (ret == PAGE_SIZE)
if (ret >= PAGE_SIZE)
ret = -E2BIG;
}
spin_unlock(&ocfs2_stack_lock);