4.18-stable review patch. If anyone has any objections, please let me know.
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From: Richard Weinberger richard@nod.at
commit 95a22d2084d72ea067d8323cc85677dba5d97cae upstream.
Check whether the size is within bounds before using it. If the size is not correct, abort and dump the bad data node.
Cc: Kees Cook keescook@chromium.org Cc: Silvio Cesare silvio.cesare@gmail.com Cc: stable@vger.kernel.org Fixes: 1e51764a3c2ac ("UBIFS: add new flash file system") Reported-by: Silvio Cesare silvio.cesare@gmail.com Signed-off-by: Richard Weinberger richard@nod.at Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ubifs/journal.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
--- a/fs/ubifs/journal.c +++ b/fs/ubifs/journal.c @@ -1387,7 +1387,16 @@ int ubifs_jnl_truncate(struct ubifs_info else if (err) goto out_free; else { - if (le32_to_cpu(dn->size) <= dlen) + int dn_len = le32_to_cpu(dn->size); + + if (dn_len <= 0 || dn_len > UBIFS_BLOCK_SIZE) { + ubifs_err(c, "bad data node (block %u, inode %lu)", + blk, inode->i_ino); + ubifs_dump_node(c, dn); + goto out_free; + } + + if (dn_len <= dlen) dlen = 0; /* Nothing to do */ else { err = truncate_data_node(c, inode, blk, dn, &dlen);