4.19-stable review patch. If anyone has any objections, please let me know.
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From: Jeongjun Park aha310510@gmail.com
commit c4a7dc9523b59b3e73fd522c73e95e072f876b16 upstream.
The size of the nilfs_type_by_mode array in the fs/nilfs2/dir.c file is defined as "S_IFMT >> S_SHIFT", but the nilfs_set_de_type() function, which uses this array, specifies the index to read from the array in the same way as "(mode & S_IFMT) >> S_SHIFT".
static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode) { umode_t mode = inode->i_mode;
de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; // oob }
However, when the index is determined this way, an out-of-bounds (OOB) error occurs by referring to an index that is 1 larger than the array size when the condition "mode & S_IFMT == S_IFMT" is satisfied. Therefore, a patch to resize the nilfs_type_by_mode array should be applied to prevent OOB errors.
Link: https://lkml.kernel.org/r/20240415182048.7144-1-konishi.ryusuke@gmail.com Reported-by: syzbot+2e22057de05b9f3b30d8@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2e22057de05b9f3b30d8 Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations") Signed-off-by: Jeongjun Park aha310510@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nilfs2/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -243,7 +243,7 @@ nilfs_filetype_table[NILFS_FT_MAX] = {
#define S_SHIFT 12 static unsigned char -nilfs_type_by_mode[S_IFMT >> S_SHIFT] = { +nilfs_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = { [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE, [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR, [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,