The patch titled
Subject: ocfs2: fix snprintf() checking
has been added to the -mm tree. Its filename is
ocfs2-fix-snprintf-checking.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/ocfs2-fix-snprintf-checking.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/ocfs2-fix-snprintf-checking.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Subject: ocfs2: fix snprintf() checking
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: a860f6eb4c6a ("ocfs2: sysfile interfaces for online file check")
Fixes: 74ae4e104dfc ("ocfs2: Create stack glue sysfs files.")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Changwei Ge <gechangwei@xxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/filecheck.c | 6 +-----
fs/ocfs2/stackglue.c | 8 ++------
2 files changed, 3 insertions(+), 11 deletions(-)
--- a/fs/ocfs2/filecheck.c~ocfs2-fix-snprintf-checking
+++ a/fs/ocfs2/filecheck.c
@@ -326,11 +326,7 @@ static ssize_t ocfs2_filecheck_attr_show
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;
--- a/fs/ocfs2/stackglue.c~ocfs2-fix-snprintf-checking
+++ a/fs/ocfs2/stackglue.c
@@ -500,11 +500,7 @@ static ssize_t ocfs2_loaded_cluster_plug
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;
@@ -531,7 +527,7 @@ static ssize_t ocfs2_active_cluster_plug
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);
_
Patches currently in -mm which might be from dan.carpenter@xxxxxxxxxx are
ocfs2-fix-snprintf-checking.patch
