This is a note to let you know that I've just added the patch titled
staging: erofs: avoid endless loop of invalid lookback distance 0
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the staging-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 07ae24a38ac0254a5d955e4646806b756a426c0c Mon Sep 17 00:00:00 2001
From: Gao Xiang <gaoxiang25@xxxxxxxxxx>
Date: Mon, 19 Aug 2019 18:34:26 +0800
Subject: staging: erofs: avoid endless loop of invalid lookback distance 0
As reported by erofs-utils fuzzer, Lookback distance should
be a positive number, so it should be actually looked back
rather than spinning.
Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.19+
Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx>
Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20190819103426.87579-7-gaoxiang25@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/erofs/zmap.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/staging/erofs/zmap.c b/drivers/staging/erofs/zmap.c
index 7408e86823a4..774dacbc5b32 100644
--- a/drivers/staging/erofs/zmap.c
+++ b/drivers/staging/erofs/zmap.c
@@ -350,6 +350,12 @@ static int vle_extent_lookback(struct z_erofs_maprecorder *m,
switch (m->type) {
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ if (unlikely(!m->delta[0])) {
+ errln("invalid lookback distance 0 at nid %llu",
+ vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
return vle_extent_lookback(m, m->delta[0]);
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
map->m_flags &= ~EROFS_MAP_ZIPPED;
--
2.23.0
