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".

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230605170553.7835-2-andriy.shevchenko@linux.intel.com
This commit is contained in:
Andy Shevchenko 2023-06-05 20:05:51 +03:00 committed by Kees Cook
parent 8515e4a746
commit 7afb6d8fa8

View file

@ -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;