From: Pali Rohár pali@kernel.org
[ Upstream commit e255612b5ed9f179abe8196df7c2ba09dd227900 ]
Some operations, like WRITE, does not require FILE_READ_ATTRIBUTES access.
So when FILE_READ_ATTRIBUTES is not explicitly requested for smb2_open_file() then first try to do SMB2 CREATE with FILE_READ_ATTRIBUTES access (like it was before) and then fallback to SMB2 CREATE without FILE_READ_ATTRIBUTES access (less common case).
This change allows to complete WRITE operation to a file when it does not grant FILE_READ_ATTRIBUTES permission and its parent directory does not grant READ_DATA permission (parent directory READ_DATA is implicit grant of child FILE_READ_ATTRIBUTES permission).
Signed-off-by: Pali Rohár pali@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/smb/client/smb2file.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/smb/client/smb2file.c b/fs/smb/client/smb2file.c index db9c807115c60..d7f2835e0b1cc 100644 --- a/fs/smb/client/smb2file.c +++ b/fs/smb/client/smb2file.c @@ -107,16 +107,25 @@ int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32 int err_buftype = CIFS_NO_BUFFER; struct cifs_fid *fid = oparms->fid; struct network_resiliency_req nr_ioctl_req; + bool retry_without_read_attributes = false;
smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb); if (smb2_path == NULL) return -ENOMEM;
- oparms->desired_access |= FILE_READ_ATTRIBUTES; + if (!(oparms->desired_access & FILE_READ_ATTRIBUTES)) { + oparms->desired_access |= FILE_READ_ATTRIBUTES; + retry_without_read_attributes = true; + } smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;
rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov, &err_buftype); + if (rc == -EACCES && retry_without_read_attributes) { + oparms->desired_access &= ~FILE_READ_ATTRIBUTES; + rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov, + &err_buftype); + } if (rc && data) { struct smb2_hdr *hdr = err_iov.iov_base;