From: Gao Xiang <xiang@kernel.org>
To: linux-erofs@lists.ozlabs.org
Cc: LKML <linux-kernel@vger.kernel.org>, Gao Xiang <xiang@kernel.org>
Subject: [PATCH] erofs: guard on-disk algorithm IDs against Z_EROFS_COMPRESSION_MAX
Date: Fri, 14 Aug 2026 16:14:37 +0800 [thread overview]
Message-ID: <20260814081437.86684-1-xiang@kernel.org> (raw)
All on-disk algorithm IDs should be validated against
supported Z_EROFS_COMPRESSION_MAX.
This includes a partial revert of a previous commit and also adds
validation for encoded extents.
Fixes: 131897c65e2b ("erofs: fix invalid algorithm for encoded extents")
Signed-off-by: Gao Xiang <xiang@kernel.org>
---
fs/erofs/internal.h | 2 +-
fs/erofs/zmap.c | 35 +++++++++++++++++++++--------------
2 files changed, 22 insertions(+), 15 deletions(-)
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 6de6e5a58e6b..9b7370f0f3df 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -267,7 +267,7 @@ struct erofs_inode {
#ifdef CONFIG_EROFS_FS_ZIP
struct {
unsigned short z_advise;
- unsigned char z_algorithmtype[2];
+ unsigned char z_algofmt[2];
unsigned char z_lclusterbits;
union {
u64 z_tailextent_headlcn;
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index b5411b579fd9..b316a50efe38 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -488,10 +488,9 @@ static int z_erofs_map_blocks_fo(struct inode *inode,
map->m_algorithmformat = Z_EROFS_COMPRESSION_INTERLACED;
else
map->m_algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
- } else if (m.headtype == Z_EROFS_LCLUSTER_TYPE_HEAD2) {
- map->m_algorithmformat = vi->z_algorithmtype[1];
} else {
- map->m_algorithmformat = vi->z_algorithmtype[0];
+ map->m_algorithmformat =
+ vi->z_algofmt[m.headtype == Z_EROFS_LCLUSTER_TYPE_HEAD2];
}
if ((flags & EROFS_GET_BLOCKS_FIEMAP) ||
@@ -605,9 +604,14 @@ static int z_erofs_map_blocks_ext(struct inode *inode,
if (map->m_plen & Z_EROFS_EXTENT_PLEN_PARTIAL)
map->m_flags |= EROFS_MAP_PARTIAL_REF;
map->m_plen &= Z_EROFS_EXTENT_PLEN_MASK;
- if (fmt)
- map->m_algorithmformat = fmt - 1;
- else if (interlaced && !((map->m_pa | map->m_plen) & bmask))
+ if (fmt) {
+ map->m_algorithmformat = --fmt;
+ if (fmt >= Z_EROFS_COMPRESSION_MAX) {
+ erofs_err(sb, "unknown algorithm %d @ pos %llu for nid %llu, please upgrade kernel",
+ fmt, map->m_la, vi->nid);
+ return -EOPNOTSUPP;
+ }
+ } else if (interlaced && !((map->m_pa | map->m_plen) & bmask))
map->m_algorithmformat =
Z_EROFS_COMPRESSION_INTERLACED;
else
@@ -625,7 +629,7 @@ static int z_erofs_fill_inode(struct inode *inode, struct erofs_map_blocks *map)
struct super_block *const sb = inode->i_sb;
struct z_erofs_map_header *h;
erofs_off_t pos;
- int err = 0;
+ int err = 0, nr;
if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags)) {
/*
@@ -668,12 +672,19 @@ static int z_erofs_fill_inode(struct inode *inode, struct erofs_map_blocks *map)
goto done;
}
- vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
- vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
if (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)
vi->z_fragmentoff = le32_to_cpu(h->h_fragmentoff);
else if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER)
vi->z_idata_size = le16_to_cpu(h->h_idata_size);
+ for (nr = 0; nr < 2; ++nr) {
+ vi->z_algofmt[nr] = (h->h_algorithmtype >> (4 * nr)) & 15;
+ if (vi->z_algofmt[nr] >= Z_EROFS_COMPRESSION_MAX) {
+ erofs_err(sb, "unknown HEAD%u format %u for nid %llu, please upgrade kernel",
+ nr + 1, vi->z_algofmt[nr], vi->nid);
+ err = -EOPNOTSUPP;
+ goto out_unlock;
+ }
+ }
if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
@@ -721,12 +732,8 @@ static int z_erofs_map_sanity_check(struct inode *inode,
if (!(map->m_flags & EROFS_MAP_MAPPED))
return 0;
- if (unlikely(map->m_algorithmformat >= Z_EROFS_COMPRESSION_RUNTIME_MAX)) {
- erofs_err(inode->i_sb, "unknown algorithm %d @ pos %llu for nid %llu, please upgrade kernel",
- map->m_algorithmformat, map->m_la, EROFS_I(inode)->nid);
- return -EOPNOTSUPP;
- }
+ DBG_BUGON(map->m_algorithmformat >= Z_EROFS_COMPRESSION_RUNTIME_MAX);
if (map->m_algorithmformat < Z_EROFS_COMPRESSION_MAX) {
if (!(sbi->available_compr_algs & BIT(map->m_algorithmformat))) {
erofs_err(inode->i_sb, "inconsistent algorithmtype %u for nid %llu",
--
2.47.3
reply other threads:[~2026-08-14 8:15 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260814081437.86684-1-xiang@kernel.org \
--to=xiang@kernel.org \
--cc=linux-erofs@lists.ozlabs.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.