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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2023-06-05 20:05:51 +0300
committerKees Cook <keescook@chromium.org>2023-06-05 15:31:12 -0700
commit7afb6d8fa81fd8d332f70ead5e35d8c90abb8165 (patch)
treec843ef681c8a20274965d8c4482ee2e1ba9ef680 /fs/jbd2/journal.c
parent8515e4a746fcb888fa6c320242eccf4c1d402465 (diff)
downloadlinux-7afb6d8fa81fd8d332f70ead5e35d8c90abb8165.tar.gz
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
Diffstat (limited to 'fs/jbd2/journal.c')
-rw-r--r--fs/jbd2/journal.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8ae419152ff64..6e17f8f94dfd5 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;