| Message ID | 20200820092126.196020416@linuxfoundation.org |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Thu, Aug 20, 2020 at 11:21:27AM +0200, Greg Kroah-Hartman wrote: > From: Jaegeuk Kim <jaegeuk@kernel.org> > > [ Upstream commit 4e240d1bab1ead280ddf5eb05058dba6bbd57d10 ] > > If namelen is corrupted to have very long value, fill_dentries can copy > wrong memory area. > > Reviewed-by: Chao Yu <yuchao0@huawei.com> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > fs/f2fs/dir.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c > index 92a240616f520..5411d6667781f 100644 > --- a/fs/f2fs/dir.c > +++ b/fs/f2fs/dir.c > @@ -805,6 +805,16 @@ bool 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(F2FS_I_SB(d->inode)->sb, KERN_WARNING, > + "%s: corrupted namelen=%d, run fsck to fix.", > + __func__, le16_to_cpu(de->name_len)); > + set_sbi_flag(F2FS_I_SB(d->inode)->sb->s_fs_info, SBI_NEED_FSCK); > + return -EINVAL; > + } > + > if (f2fs_encrypted_inode(d->inode)) { > int save_len = fstr->len; > int ret; > @@ -829,7 +839,6 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, > le32_to_cpu(de->ino), d_type)) > return true; > > - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len)); > ctx->pos = start_pos + bit_pos; This buggy backport broke f2fs encryption in 4.4-stable, due to a missing prerequisite commit (https://lkml.kernel.org/stable/20201031195809.377983-1-ebiggers@kernel.org/). Why didn't this backport get Cc'ed to the subsystem mailing list? It wasn't even a clean cherry pick. - Eric
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 92a240616f520..5411d6667781f 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -805,6 +805,16 @@ bool 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(F2FS_I_SB(d->inode)->sb, KERN_WARNING, + "%s: corrupted namelen=%d, run fsck to fix.", + __func__, le16_to_cpu(de->name_len)); + set_sbi_flag(F2FS_I_SB(d->inode)->sb->s_fs_info, SBI_NEED_FSCK); + return -EINVAL; + } + if (f2fs_encrypted_inode(d->inode)) { int save_len = fstr->len; int ret; @@ -829,7 +839,6 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, le32_to_cpu(de->ino), d_type)) return true; - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len)); ctx->pos = start_pos + bit_pos; } return false;