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| author | Leo Stone <leocstone@gmail.com> | 2024-11-30 21:14:19 -0800 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-12-02 15:32:19 +0100 |
| commit | b905bafdea21a75d75a96855edd9e0b6051eee30 (patch) | |
| tree | 86812751233eed063db6e26a104bd00f84b1be2b | |
| parent | 40384c840ea1944d7c5a392e8975ed088ecf0b37 (diff) | |
| download | linux-b905bafdea21a75d75a96855edd9e0b6051eee30.tar.gz linux-b905bafdea21a75d75a96855edd9e0b6051eee30.tar.bz2 linux-b905bafdea21a75d75a96855edd9e0b6051eee30.zip | |
hfs: Sanity check the root record
In the syzbot reproducer, the hfs_cat_rec for the root dir has type
HFS_CDR_FIL after being read with hfs_bnode_read() in hfs_super_fill().
This indicates it should be used as an hfs_cat_file, which is 102 bytes.
Only the first 70 bytes of that struct are initialized, however,
because the entrylength passed into hfs_bnode_read() is still the length of
a directory record. This causes uninitialized values to be used later on,
when the hfs_cat_rec union is treated as the larger hfs_cat_file struct.
Add a check to make sure the retrieved record has the correct type
for the root directory (HFS_CDR_DIR), and make sure we load the correct
number of bytes for a directory record.
Reported-by: syzbot+2db3c7526ba68f4ea776@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2db3c7526ba68f4ea776
Tested-by: syzbot+2db3c7526ba68f4ea776@syzkaller.appspotmail.com
Tested-by: Leo Stone <leocstone@gmail.com>
Signed-off-by: Leo Stone <leocstone@gmail.com>
Link: https://lore.kernel.org/r/20241201051420.77858-1-leocstone@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | fs/hfs/super.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/hfs/super.c b/fs/hfs/super.c index 3bee9b5dba5e..fe09c2093a93 100644 --- a/fs/hfs/super.c +++ b/fs/hfs/super.c @@ -349,11 +349,13 @@ static int hfs_fill_super(struct super_block *sb, struct fs_context *fc) goto bail_no_root; res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd); if (!res) { - if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) { + if (fd.entrylength != sizeof(rec.dir)) { res = -EIO; goto bail_hfs_find; } hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength); + if (rec.type != HFS_CDR_DIR) + res = -EIO; } if (res) goto bail_hfs_find; |