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Commit fcf83067 authored by Al Viro's avatar Al Viro
Browse files

vfs: fix compat_sys_stat() handling of overflows in st_nlink 



Massaged cp_compat_stat() into form closer to cp_new_stat(); the only
real issue had been in handling of st_nlink overflows - native 32bit
stat(2) returns -EOVERFLOW in such situations, compat one silently
loses upper bits.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent dcdbed85

fs/compat.c

+25 −31
Original line number Diff line number Diff line
@@ -131,41 +131,35 @@ asmlinkage long compat_sys_utimes(const char __user *filename, struct compat_tim 


static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)

{

	compat_ino_t ino = stat->ino;

	typeof(ubuf->st_uid) uid = 0;

	typeof(ubuf->st_gid) gid = 0;

	int err;

	struct compat_stat tmp;



	SET_UID(uid, stat->uid);

	SET_GID(gid, stat->gid);

	if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))

		return -EOVERFLOW;



	if ((u64) stat->size > MAX_NON_LFS ||

	    !old_valid_dev(stat->dev) ||

	    !old_valid_dev(stat->rdev))

	memset(&tmp, 0, sizeof(tmp));

	tmp.st_dev = old_encode_dev(stat->dev);

	tmp.st_ino = stat->ino;

	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)

		return -EOVERFLOW;

	if (sizeof(ino) < sizeof(stat->ino) && ino != stat->ino)

	tmp.st_mode = stat->mode;

	tmp.st_nlink = stat->nlink;

	if (tmp.st_nlink != stat->nlink)

		return -EOVERFLOW;



	if (clear_user(ubuf, sizeof(*ubuf)))

		return -EFAULT;



	err  = __put_user(old_encode_dev(stat->dev), &ubuf->st_dev);

	err |= __put_user(ino, &ubuf->st_ino);

	err |= __put_user(stat->mode, &ubuf->st_mode);

	err |= __put_user(stat->nlink, &ubuf->st_nlink);

	err |= __put_user(uid, &ubuf->st_uid);

	err |= __put_user(gid, &ubuf->st_gid);

	err |= __put_user(old_encode_dev(stat->rdev), &ubuf->st_rdev);

	err |= __put_user(stat->size, &ubuf->st_size);

	err |= __put_user(stat->atime.tv_sec, &ubuf->st_atime);

	err |= __put_user(stat->atime.tv_nsec, &ubuf->st_atime_nsec);

	err |= __put_user(stat->mtime.tv_sec, &ubuf->st_mtime);

	err |= __put_user(stat->mtime.tv_nsec, &ubuf->st_mtime_nsec);

	err |= __put_user(stat->ctime.tv_sec, &ubuf->st_ctime);

	err |= __put_user(stat->ctime.tv_nsec, &ubuf->st_ctime_nsec);

	err |= __put_user(stat->blksize, &ubuf->st_blksize);

	err |= __put_user(stat->blocks, &ubuf->st_blocks);

	return err;

	SET_UID(tmp.st_uid, stat->uid);

	SET_GID(tmp.st_gid, stat->gid);

	tmp.st_rdev = old_encode_dev(stat->rdev);

	if ((u64) stat->size > MAX_NON_LFS)

		return -EOVERFLOW;

	tmp.st_size = stat->size;

	tmp.st_atime = stat->atime.tv_sec;

	tmp.st_atime_nsec = stat->atime.tv_nsec;

	tmp.st_mtime = stat->mtime.tv_sec;

	tmp.st_mtime_nsec = stat->mtime.tv_nsec;

	tmp.st_ctime = stat->ctime.tv_sec;

	tmp.st_ctime_nsec = stat->ctime.tv_nsec;

	tmp.st_blocks = stat->blocks;

	tmp.st_blksize = stat->blksize;

	return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;

}



asmlinkage long compat_sys_newstat(const char __user * filename,