From: Christian Brauner <christian.brauner@xxxxxxxxxx>
commit 3cb6ee991496b67ee284c6895a0ba007e2d7bac3 upstream.
The 9P2000.L setattr method v9fs_vfs_setattr_dotl() copies struct iattr
values without checking whether they are valid causing unitialized
values to be copied. The 9P2000 setattr method v9fs_vfs_setattr() method
gets this right. Check whether struct iattr fields are valid first
before copying in v9fs_vfs_setattr_dotl() too and make sure that all
other fields are set to 0 apart from {g,u}id which should be set to
INVALID_{G,U}ID. This ensure that they can be safely sent over the wire
or printed for debugging later on.
Link: https://lkml.kernel.org/r/20211129114434.3637938-1-brauner@xxxxxxxxxx
Link: https://lkml.kernel.org/r/000000000000a0d53f05d1c72a4c%40google.com
Cc: Eric Van Hensbergen <ericvh@xxxxxxxxx>
Cc: Latchesar Ionkov <lucho@xxxxxxxxxx>
Cc: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
Cc: v9fs-developer@xxxxxxxxxxxxxxxxxxxxx
Reported-by: syzbot+dfac92a50024b54acaa4@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
[Dominique: do not set a/mtime with just ATTR_A/MTIME as discussed]
Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/9p/vfs_inode_dotl.c | 29 ++++++++++++++++++++---------
1 file changed, 20 insertions(+), 9 deletions(-)
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -541,7 +541,10 @@ int v9fs_vfs_setattr_dotl(struct dentry
{
int retval;
struct p9_fid *fid = NULL;
- struct p9_iattr_dotl p9attr;
+ struct p9_iattr_dotl p9attr = {
+ .uid = INVALID_UID,
+ .gid = INVALID_GID,
+ };
struct inode *inode = d_inode(dentry);
p9_debug(P9_DEBUG_VFS, "\n");
@@ -551,14 +554,22 @@ int v9fs_vfs_setattr_dotl(struct dentry
return retval;
p9attr.valid = v9fs_mapped_iattr_valid(iattr->ia_valid);
- p9attr.mode = iattr->ia_mode;
- p9attr.uid = iattr->ia_uid;
- p9attr.gid = iattr->ia_gid;
- p9attr.size = iattr->ia_size;
- p9attr.atime_sec = iattr->ia_atime.tv_sec;
- p9attr.atime_nsec = iattr->ia_atime.tv_nsec;
- p9attr.mtime_sec = iattr->ia_mtime.tv_sec;
- p9attr.mtime_nsec = iattr->ia_mtime.tv_nsec;
+ if (iattr->ia_valid & ATTR_MODE)
+ p9attr.mode = iattr->ia_mode;
+ if (iattr->ia_valid & ATTR_UID)
+ p9attr.uid = iattr->ia_uid;
+ if (iattr->ia_valid & ATTR_GID)
+ p9attr.gid = iattr->ia_gid;
+ if (iattr->ia_valid & ATTR_SIZE)
+ p9attr.size = iattr->ia_size;
+ if (iattr->ia_valid & ATTR_ATIME_SET) {
+ p9attr.atime_sec = iattr->ia_atime.tv_sec;
+ p9attr.atime_nsec = iattr->ia_atime.tv_nsec;
+ }
+ if (iattr->ia_valid & ATTR_MTIME_SET) {
+ p9attr.mtime_sec = iattr->ia_mtime.tv_sec;
+ p9attr.mtime_nsec = iattr->ia_mtime.tv_nsec;
+ }
if (iattr->ia_valid & ATTR_FILE) {
fid = iattr->ia_file->private_data;
