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f2fs: check memory boundary by insane namelen

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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>
This commit is contained in:
Jaegeuk Kim 2018-11-14 12:40:30 -08:00
parent 1e771e83ce
commit 4e240d1bab
1 changed files with 11 additions and 1 deletions
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12
fs/f2fs/dir.c
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@ -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.name = d->filename[bit_pos];
de_name.len = le16_to_cpu(de->name_len); 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)) { if (f2fs_encrypted_inode(d->inode)) {
int save_len = fstr->len; 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) if (readdir_ra)
f2fs_ra_node_page(sbi, le32_to_cpu(de->ino)); 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; ctx->pos = start_pos + bit_pos;
} }
out: out: