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authorLinus Torvalds <torvalds@linux-foundation.org>2020-05-20 11:28:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-05-20 11:28:35 -0700
commit8e2b7f634a851fb711a7e693e00905fc6c05b74b (patch)
treec35d2e2f5e052b77d47e53ab1c41f49137a508c6 /fs
parent566d136289dc57816ac290de87a9a0f7d9bd3cbb (diff)
parent9aafc1b0187322fa4fd4eb905d0903172237206c (diff)
Merge tag 'ovl-fixes-5.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs fixes from Miklos Szeredi: "Fix two bugs introduced in this cycle and one introduced in v5.5" * tag 'ovl-fixes-5.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: potential crash in ovl_fid_to_fh() ovl: clear ATTR_OPEN from attr->ia_valid ovl: clear ATTR_FILE from attr->ia_valid
Diffstat (limited to 'fs')
-rw-r--r--fs/overlayfs/export.c3
-rw-r--r--fs/overlayfs/inode.c18
2 files changed, 21 insertions, 0 deletions
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 475c61f53f0f..ed5c1078919c 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -783,6 +783,9 @@ static struct ovl_fh *ovl_fid_to_fh(struct fid *fid, int buflen, int fh_type)
if (fh_type != OVL_FILEID_V0)
return ERR_PTR(-EINVAL);
+ if (buflen <= OVL_FH_WIRE_OFFSET)
+ return ERR_PTR(-EINVAL);
+
fh = kzalloc(buflen, GFP_KERNEL);
if (!fh)
return ERR_PTR(-ENOMEM);
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index b0d42ece4d7c..981f11ec51bc 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -58,6 +58,24 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
attr->ia_valid &= ~ATTR_MODE;
+ /*
+ * We might have to translate ovl file into real file object
+ * once use cases emerge. For now, simply don't let underlying
+ * filesystem rely on attr->ia_file
+ */
+ attr->ia_valid &= ~ATTR_FILE;
+
+ /*
+ * If open(O_TRUNC) is done, VFS calls ->setattr with ATTR_OPEN
+ * set. Overlayfs does not pass O_TRUNC flag to underlying
+ * filesystem during open -> do not pass ATTR_OPEN. This
+ * disables optimization in fuse which assumes open(O_TRUNC)
+ * already set file size to 0. But we never passed O_TRUNC to
+ * fuse. So by clearing ATTR_OPEN, fuse will be forced to send
+ * setattr request to server.
+ */
+ attr->ia_valid &= ~ATTR_OPEN;
+
inode_lock(upperdentry->d_inode);
old_cred = ovl_override_creds(dentry->d_sb);
err = notify_change(upperdentry, attr, NULL);