diff options
| author | Ran Hongyun <ranhongyun1@huawei.com> | 2026-07-13 19:55:25 +0800 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-09-16 10:26:47 +0200 |
| commit | 1f7745fb3580152ca902ef181b605f33cabfb1d0 (patch) | |
| tree | 6f1fe5c9fb273eee61158d52d6c9de7d2eac598c /fs/squashfs | |
| parent | 1abd643f3783ea8f8e273c18697ff0413aa92dc7 (diff) | |
squashfs: Add dictionary size range check to prevent shift-out-of-bounds
When an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size
is 0) is mounted, and performs shift operations using dictionarysize, the
shift exponent is -1, causing a shift-out-of-bounds.
Detail as below:
squashfs_comp_opts(msblk, buffer, length)
squashfs_xz_comp_opts()
if (comp_opts)
n = ffs(opts->dict_size) - 1;<----opts->dict_size=0, n=-1
if (opts->dict_size != (1 << n) && opts->dict_size !=
(1 << n) + (1 << (n + 1))) <----shift-out-of-bounds
Fix it by adding a dictionary size range check before the shift operation.
Fixes: ff750311d30a ("Squashfs: add compression options support to xz decompressor")
Signed-off-by: Ran Hongyun <ranhongyun1@huawei.com>
Link: https://patch.msgid.link/20260713115525.2661734-1-ranhongyun1@huawei.com
Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Diffstat (limited to 'fs/squashfs')
| -rw-r--r-- | fs/squashfs/xz_wrapper.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c index 0a4ff3ec9c8c..6610af241449 100644 --- a/fs/squashfs/xz_wrapper.c +++ b/fs/squashfs/xz_wrapper.c @@ -57,10 +57,10 @@ static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk, opts->dict_size = le32_to_cpu(comp_opts->dictionary_size); - /* the dictionary size should be 2^n or 2^n+2^(n+1) */ + /* the dictionary size should be positive and 2^n or 2^n+2^(n+1) */ n = ffs(opts->dict_size) - 1; - if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + - (1 << (n + 1))) { + if (opts->dict_size <= 0 || (opts->dict_size != (1 << n) && + opts->dict_size != (1 << n) + (1 << (n + 1)))) { err = -EIO; goto out; } |