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| author | Jingbo Xu <jefflexu@linux.alibaba.com> | 2022-10-21 05:31:53 +0300 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-11-10 04:53:20 +0300 |
| commit | 39bfcb8138f6dc3375f23b1e62ccfc7c0d83295d (patch) | |
| tree | 158096b93d6c55fa5ab086c824a676a44b52284e /fs/erofs/fscache.c | |
| parent | e6d9f9ba111b56154f1b1120252aff269cebd49c (diff) | |
| download | linux-39bfcb8138f6dc3375f23b1e62ccfc7c0d83295d.tar.xz | |
erofs: fix use-after-free of fsid and domain_id string
When erofs instance is remounted with fsid or domain_id mount option
specified, the original fsid and domain_id string pointer in sbi->opt
is directly overridden with the fsid and domain_id string in the new
fs_context, without freeing the original fsid and domain_id string.
What's worse, when the new fsid and domain_id string is transferred to
sbi, they are not reset to NULL in fs_context, and thus they are freed
when remount finishes, while sbi is still referring to these strings.
Reconfiguration for fsid and domain_id seems unusual. Thus clarify this
restriction explicitly and dump a warning when users are attempting to
do this.
Besides, to fix the use-after-free issue, move fsid and domain_id from
erofs_mount_opts to outside.
Fixes: c6be2bd0a5dd ("erofs: register fscache volume")
Fixes: 8b7adf1dff3d ("erofs: introduce fscache-based domain")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20221021023153.1330-1-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/fscache.c')
| -rw-r--r-- | fs/erofs/fscache.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 260fa4737fc0..6eaf4a4ab95c 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -406,13 +406,13 @@ static void erofs_fscache_domain_put(struct erofs_domain *domain) static int erofs_fscache_register_volume(struct super_block *sb) { struct erofs_sb_info *sbi = EROFS_SB(sb); - char *domain_id = sbi->opt.domain_id; + char *domain_id = sbi->domain_id; struct fscache_volume *volume; char *name; int ret = 0; name = kasprintf(GFP_KERNEL, "erofs,%s", - domain_id ? domain_id : sbi->opt.fsid); + domain_id ? domain_id : sbi->fsid); if (!name) return -ENOMEM; @@ -438,7 +438,7 @@ static int erofs_fscache_init_domain(struct super_block *sb) if (!domain) return -ENOMEM; - domain->domain_id = kstrdup(sbi->opt.domain_id, GFP_KERNEL); + domain->domain_id = kstrdup(sbi->domain_id, GFP_KERNEL); if (!domain->domain_id) { kfree(domain); return -ENOMEM; @@ -475,7 +475,7 @@ static int erofs_fscache_register_domain(struct super_block *sb) mutex_lock(&erofs_domain_list_lock); list_for_each_entry(domain, &erofs_domain_list, list) { - if (!strcmp(domain->domain_id, sbi->opt.domain_id)) { + if (!strcmp(domain->domain_id, sbi->domain_id)) { sbi->domain = domain; sbi->volume = domain->volume; refcount_inc(&domain->ref); @@ -612,7 +612,7 @@ struct erofs_fscache *erofs_domain_register_cookie(struct super_block *sb, struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb, char *name, bool need_inode) { - if (EROFS_SB(sb)->opt.domain_id) + if (EROFS_SB(sb)->domain_id) return erofs_domain_register_cookie(sb, name, need_inode); return erofs_fscache_acquire_cookie(sb, name, need_inode); } @@ -644,7 +644,7 @@ int erofs_fscache_register_fs(struct super_block *sb) struct erofs_sb_info *sbi = EROFS_SB(sb); struct erofs_fscache *fscache; - if (sbi->opt.domain_id) + if (sbi->domain_id) ret = erofs_fscache_register_domain(sb); else ret = erofs_fscache_register_volume(sb); @@ -652,7 +652,7 @@ int erofs_fscache_register_fs(struct super_block *sb) return ret; /* acquired domain/volume will be relinquished in kill_sb() on error */ - fscache = erofs_fscache_register_cookie(sb, sbi->opt.fsid, true); + fscache = erofs_fscache_register_cookie(sb, sbi->fsid, true); if (IS_ERR(fscache)) return PTR_ERR(fscache); |