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f2fs: check memory boundary by insane namelen

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[ 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>
This commit is contained in:
Jaegeuk Kim 2018-11-14 12:40:30 -08:00 committed by Greg Kroah-Hartman
parent 16d15f971c
commit f46a09b74a
1 changed files with 10 additions and 1 deletions

11
fs/f2fs/dir.c

@ -843,6 +843,16 @@ 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 err;
@ -861,7 +871,6 @@ 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;