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Kernel/Ext2: Avoid overflow when updating UID and GID values

Browse source 
Previously, attempting to update an ext2 inode with a UID or GID
larger than 65535 would overflow. We now write the high bits of UIDs
and GIDs to the same place that Linux does within the `osd2` struct.
This commit is contained in:
Tim Ledbetter 2023-10-01 16:41:12 +01:00 • committed by Andreas Kling
parent 7e10f76021
commit db929e0fcf
5 changed files with 47 additions and 7 deletions
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6
Kernel/FileSystem/Ext2FS/FileSystem.cpp
View file

@ -510,8 +510,10 @@ ErrorOr<NonnullRefPtr<Inode>> Ext2FS::create_inode(Ext2FSInode& parent_inode, St
ext2_inode e2inode {};
auto now = kgettimeofday().truncated_seconds_since_epoch();
e2inode.i_mode = mode;
e2inode.i_uid = uid.value();
e2inode.i_gid = gid.value();
e2inode.i_uid = static_cast<u16>(uid.value());
ext2fs_set_i_uid_high(e2inode, uid.value() >> 16);
e2inode.i_gid = static_cast<u16>(gid.value());
ext2fs_set_i_gid_high(e2inode, gid.value() >> 16);
e2inode.i_size = 0;
e2inode.i_atime = now;
e2inode.i_ctime = now;

12
Kernel/FileSystem/Ext2FS/Inode.cpp
View file

@ -471,8 +471,8 @@ InodeMetadata Ext2FSInode::metadata() const
metadata.inode = identifier();
metadata.size = size();
metadata.mode = m_raw_inode.i_mode;
metadata.uid = m_raw_inode.i_uid;
metadata.gid = m_raw_inode.i_gid;
metadata.uid = inode_uid(m_raw_inode);
metadata.gid = inode_gid(m_raw_inode);
metadata.link_count = m_raw_inode.i_links_count;
metadata.atime = UnixDateTime::from_seconds_since_epoch(m_raw_inode.i_atime);
metadata.ctime = UnixDateTime::from_seconds_since_epoch(m_raw_inode.i_ctime);
@ -1051,10 +1051,12 @@ ErrorOr<void> Ext2FSInode::chmod(mode_t mode)
ErrorOr<void> Ext2FSInode::chown(UserID uid, GroupID gid)
{
MutexLocker locker(m_inode_lock);
if (m_raw_inode.i_uid == uid && m_raw_inode.i_gid == gid)
if (inode_uid(m_raw_inode) == uid && inode_gid(m_raw_inode) == gid)
return {};
m_raw_inode.i_uid = uid.value();
m_raw_inode.i_gid = gid.value();
m_raw_inode.i_uid = static_cast<u16>(uid.value());
ext2fs_set_i_uid_high(m_raw_inode, uid.value() >> 16);
m_raw_inode.i_gid = static_cast<u16>(gid.value());
ext2fs_set_i_gid_high(m_raw_inode, gid.value() >> 16);
set_metadata_dirty(true);
return {};
}