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Message-Id: <20230323123704.37983-2-andriy.shevchenko@linux.intel.com>
Date: Thu, 23 Mar 2023 14:37:02 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Kees Cook <keescook@...omium.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Cezary Rojewski <cezary.rojewski@...el.com>,
linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: "Theodore Ts'o" <tytso@....edu>, Jan Kara <jack@...e.com>,
Andy Shevchenko <andy@...nel.org>,
"Rafael J. Wysocki" <rafael@...nel.org>, Jan Kara <jack@...e.cz>
Subject: [PATCH v2 1/3] jbd2: Avoid printing outside the boundary of the buffer
Theoretically possible that "%pg" will take all room for the j_devname
and hence the "-%lu" will go outside the boundary due to unconditional
sprintf() in use. To make this code more robust, replace two sequential
s*printf():s by a single call and then replace forbidden character.
It's possible to do this way, because '/' won't ever be in the result
of "-%lu".
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Reviewed-by: Jan Kara <jack@...e.cz>
---
fs/jbd2/journal.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8ae419152ff6..6e17f8f94dfd 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1491,7 +1491,6 @@ journal_t *jbd2_journal_init_inode(struct inode *inode)
{
journal_t *journal;
sector_t blocknr;
- char *p;
int err = 0;
blocknr = 0;
@@ -1515,9 +1514,8 @@ journal_t *jbd2_journal_init_inode(struct inode *inode)
journal->j_inode = inode;
snprintf(journal->j_devname, sizeof(journal->j_devname),
- "%pg", journal->j_dev);
- p = strreplace(journal->j_devname, '/', '!');
- sprintf(p, "-%lu", journal->j_inode->i_ino);
+ "%pg-%lu", journal->j_dev, journal->j_inode->i_ino);
+ strreplace(journal->j_devname, '/', '!');
jbd2_stats_proc_init(journal);
return journal;
--
2.40.0.1.gaa8946217a0b
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