Hi, Jaegeuk and Chao, On 2018/11/15 15:50, Jaegeuk Kim wrote:
If namelen is corrupted to have very long value, fill_dentries can copy wrong memory area.
Is there any scenario that could hit this corruption? Or this is triggered by fuzzing injection? thanks, Sheng Yong
Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org> --- fs/f2fs/dir.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index bacc667950b6..c0c845da12fa 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -808,6 +808,17 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, de_name.name = d->filename[bit_pos]; de_name.len = le16_to_cpu(de->name_len);+ /* check memory boundary before moving forward */+ bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len)); + if (unlikely(bit_pos > d->max)) { + f2fs_msg(sbi->sb, KERN_WARNING, + "%s: corrupted namelen=%d, run fsck to fix.", + __func__, le16_to_cpu(de->name_len)); + set_sbi_flag(sbi, SBI_NEED_FSCK); + err = -EINVAL; + goto out; + } + if (f2fs_encrypted_inode(d->inode)) { int save_len = fstr->len;@@ -830,7 +841,6 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,if (readdir_ra) f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));- bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));ctx->pos = start_pos + bit_pos; } out:
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