| Message ID | 1505940337-79069-10-git-send-email-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com> On 09/20/2017 03:45 PM, Kees Cook wrote: > From: David Windsor <dave@nullcore.net> > > The jfs symlink pathnames, stored in struct jfs_inode_info.i_inline and > therefore contained in the jfs_ip slab cache, need to be copied to/from > userspace. > > cache object allocation: > fs/jfs/super.c: > jfs_alloc_inode(...): > ... > jfs_inode = kmem_cache_alloc(jfs_inode_cachep, GFP_NOFS); > ... > return &jfs_inode->vfs_inode; > > fs/jfs/jfs_incore.h: > JFS_IP(struct inode *inode): > return container_of(inode, struct jfs_inode_info, vfs_inode); > > fs/jfs/inode.c: > jfs_iget(...): > ... > inode->i_link = JFS_IP(inode)->i_inline; > > example usage trace: > readlink_copy+0x43/0x70 > vfs_readlink+0x62/0x110 > SyS_readlinkat+0x100/0x130 > > fs/namei.c: > readlink_copy(..., link): > ... > copy_to_user(..., link, len); > > (inlined in vfs_readlink) > generic_readlink(dentry, ...): > struct inode *inode = d_inode(dentry); > const char *link = inode->i_link; > ... > readlink_copy(..., link); > > In support of usercopy hardening, this patch defines a region in the > jfs_ip slab cache in which userspace copy operations are allowed. > > This region is known as the slab cache's usercopy region. Slab caches can > now check that each copy operation involving cache-managed memory falls > entirely within the slab's usercopy region. > > This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY > whitelisting code in the last public patch of grsecurity/PaX based on my > understanding of the code. Changes or omissions from the original code are > mine and don't reflect the original grsecurity/PaX code. > > Signed-off-by: David Windsor <dave@nullcore.net> > [kees: adjust commit log, provide usage trace] > Cc: Dave Kleikamp <shaggy@kernel.org> > Cc: jfs-discussion@lists.sourceforge.net > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > fs/jfs/super.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/fs/jfs/super.c b/fs/jfs/super.c > index 2f14677169c3..e018412608d4 100644 > --- a/fs/jfs/super.c > +++ b/fs/jfs/super.c > @@ -966,9 +966,11 @@ static int __init init_jfs_fs(void) > int rc; > > jfs_inode_cachep = > - kmem_cache_create("jfs_ip", sizeof(struct jfs_inode_info), 0, > - SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT, > - init_once); > + kmem_cache_create_usercopy("jfs_ip", sizeof(struct jfs_inode_info), > + 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT, > + offsetof(struct jfs_inode_info, i_inline), > + sizeof_field(struct jfs_inode_info, i_inline), > + init_once); > if (jfs_inode_cachep == NULL) > return -ENOMEM; > >
diff --git a/fs/jfs/super.c b/fs/jfs/super.c index 2f14677169c3..e018412608d4 100644 --- a/fs/jfs/super.c +++ b/fs/jfs/super.c @@ -966,9 +966,11 @@ static int __init init_jfs_fs(void) int rc; jfs_inode_cachep = - kmem_cache_create("jfs_ip", sizeof(struct jfs_inode_info), 0, - SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT, - init_once); + kmem_cache_create_usercopy("jfs_ip", sizeof(struct jfs_inode_info), + 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT, + offsetof(struct jfs_inode_info, i_inline), + sizeof_field(struct jfs_inode_info, i_inline), + init_once); if (jfs_inode_cachep == NULL) return -ENOMEM;