Messages in this thread | | | Date | Wed, 23 Dec 2020 11:00:13 +0100 (CET) | From | Richard Weinberger <> | Subject | Re: [PATCH] ubifs: Fix read out-of-bounds in ubifs_jnl_write_inode() |
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Chengsong Ke,
----- Ursprüngliche Mail ----- > The memory area allocated in ubifs_jnl_write_inode() is not aligned with 8 > bytes: > ino_start = ino = kmalloc(write_len, GFP_NOFS); > > When ino_start passed into write_head -> ubifs_wbuf_write_nolock: > n = aligned_len >> c->max_write_shift; > if (n) { > n <<= c->max_write_shift; > err = ubifs_leb_write(c, wbuf->lnum, buf + written, wbuf->offs, n); > // Read oob occurs here, read n bytes from buf, and buf is passed from > @ino_start which is > // not 8 bytes aligned(write_len < n). Program read (n - write_len) more bytes. > } > > Reproducer: > 0. config KASAN && apply print.patch > 1. mount ubifs on /root/temp > 2. run test.sh > 3. cd /root/temp && ls // change atime for link_file > 4. wait 1~2 minutes > > Cc: <stable@vger.kernel.org> > Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") > Link: https://bugzilla.kernel.org/show_bug.cgi?id=210865 > > Signed-off-by: Chengsong Ke <kechengsong@huawei.com> > --- > fs/ubifs/io.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-)
Good catch! Please address the problem in ubifs_jnl_write_inode(). The length there needs to be properly aligned like all other journal functions do. I think you managed to trigger the issue because ui->data_len is not aligned.
Thanks, //richard
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