From c1cf14a871528d1adba88a0128813b58d52ba926 Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Fri, 8 Mar 2024 20:57:06 +0100 Subject: [PATCH] Cygwin: try to avoid recalling offline files Chances are high that Cygwin recalls offline files from remote storage, even if the file is only accessed during stat(2) or readdir(3). To avoid this - make sure Cygwin is placeholder-aware, - open files in path_conv handling, as well as in stat(2)/readdir(3) scenarios with FILE_OPEN_NO_RECALL, and - during symlink checking or testing for executablility, don't even try to open the file if one of the OFFLINE attributes is set. Reported-by: Marcin Wisnicki Signed-off-by: Corinna Vinschen --- winsup/cygwin/autoload.cc | 1 + winsup/cygwin/dcrt0.cc | 3 +++ winsup/cygwin/fhandler/disk_file.cc | 20 ++++++++++++++------ winsup/cygwin/local_includes/ntdll.h | 8 ++++++++ winsup/cygwin/local_includes/path.h | 16 +++++++++++++++- winsup/cygwin/local_includes/winlean.h | 7 +++++++ winsup/cygwin/path.cc | 17 +++++++++++++---- 7 files changed, 61 insertions(+), 11 deletions(-) diff --git a/winsup/cygwin/autoload.cc b/winsup/cygwin/autoload.cc index 65e906e8b..cc9dafe1b 100644 --- a/winsup/cygwin/autoload.cc +++ b/winsup/cygwin/autoload.cc @@ -479,6 +479,7 @@ LoadDLLfuncEx (SetThreadDescription, KernelBase, 1) LoadDLLfunc (VirtualAlloc2, KernelBase) LoadDLLfunc (NtMapViewOfSectionEx, ntdll) +LoadDLLfuncEx (RtlSetProcessPlaceholderCompatibilityMode, ntdll, 1) LoadDLLfunc (ldap_bind_s, wldap32) LoadDLLfunc (ldap_count_entries, wldap32) diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc index fc1eec76a..ea6a18b51 100644 --- a/winsup/cygwin/dcrt0.cc +++ b/winsup/cygwin/dcrt0.cc @@ -809,6 +809,9 @@ dll_crt0_1 (void *) if (dynamically_loaded) sigproc_init (); + /* Call this before accessing any files. */ + RtlSetProcessPlaceholderCompatibilityMode (PHCM_EXPOSE_PLACEHOLDERS); + check_sanity_and_sync (user_data); /* Initialize malloc and then call user_shared_initialize since it relies diff --git a/winsup/cygwin/fhandler/disk_file.cc b/winsup/cygwin/fhandler/disk_file.cc index d08fe9160..f3592148f 100644 --- a/winsup/cygwin/fhandler/disk_file.cc +++ b/winsup/cygwin/fhandler/disk_file.cc @@ -176,7 +176,9 @@ readdir_check_reparse_point (POBJECT_ATTRIBUTES attr, bool remote) bool ret = false; status = NtOpenFile (&reph, READ_CONTROL, attr, &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_FOR_BACKUP_INTENT | FILE_OPEN_REPARSE_POINT); + FILE_OPEN_NO_RECALL + | FILE_OPEN_FOR_BACKUP_INTENT + | FILE_OPEN_REPARSE_POINT); if (NT_SUCCESS (status)) { PREPARSE_DATA_BUFFER rp = (PREPARSE_DATA_BUFFER) tp.c_get (); @@ -328,6 +330,7 @@ fhandler_base::fstat_by_name (struct stat *buf) status = NtOpenFile (&dir, SYNCHRONIZE | FILE_LIST_DIRECTORY, &attr, &io, FILE_SHARE_VALID_FLAGS, FILE_SYNCHRONOUS_IO_NONALERT + | FILE_OPEN_NO_RECALL | FILE_OPEN_FOR_BACKUP_INTENT | FILE_DIRECTORY_FILE); if (!NT_SUCCESS (status)) @@ -616,7 +619,8 @@ fhandler_disk_file::fstatvfs (struct statvfs *sfs) opened = NT_SUCCESS (NtOpenFile (&fh, READ_CONTROL, pc.get_object_attr (attr, sec_none_nih), &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_FOR_BACKUP_INTENT)); + FILE_OPEN_NO_RECALL + | FILE_OPEN_FOR_BACKUP_INTENT)); if (!opened) { /* Can't open file. Try again with parent dir. */ @@ -625,7 +629,8 @@ fhandler_disk_file::fstatvfs (struct statvfs *sfs) attr.ObjectName = &dirname; opened = NT_SUCCESS (NtOpenFile (&fh, READ_CONTROL, &attr, &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_FOR_BACKUP_INTENT)); + FILE_OPEN_NO_RECALL + | FILE_OPEN_FOR_BACKUP_INTENT)); if (!opened) goto out; } @@ -2323,7 +2328,8 @@ readdir_get_ino (const char *path, bool dot_dot) || NT_SUCCESS (NtOpenFile (&hdl, READ_CONTROL, pc.get_object_attr (attr, sec_none_nih), &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_FOR_BACKUP_INTENT + FILE_OPEN_NO_RECALL + | FILE_OPEN_FOR_BACKUP_INTENT | (pc.is_known_reparse_point () ? FILE_OPEN_REPARSE_POINT : 0))) ) @@ -2372,8 +2378,9 @@ fhandler_disk_file::readdir_helper (DIR *dir, dirent *de, DWORD w32_err, Mountpoints and unknown or unhandled reparse points will be treated as normal file/directory/unknown. In all cases, returning the INO of the reparse point (not of the target) matches behavior of posix systems. + Unless the file is OFFLINE. *. */ - if (attr & FILE_ATTRIBUTE_REPARSE_POINT) + if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) && !isoffline (attr)) { OBJECT_ATTRIBUTES oattr; @@ -2618,7 +2625,8 @@ go_ahead: &nfs_aol_ffei, sizeof nfs_aol_ffei) : NtOpenFile (&hdl, READ_CONTROL, &attr, &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_FOR_BACKUP_INTENT + FILE_OPEN_NO_RECALL + | FILE_OPEN_FOR_BACKUP_INTENT | FILE_OPEN_REPARSE_POINT); if (NT_SUCCESS (f_status)) { diff --git a/winsup/cygwin/local_includes/ntdll.h b/winsup/cygwin/local_includes/ntdll.h index 9605784e3..7737ae503 100644 --- a/winsup/cygwin/local_includes/ntdll.h +++ b/winsup/cygwin/local_includes/ntdll.h @@ -169,6 +169,13 @@ extern GUID __cygwin_socket_guid; #define FILE_VC_QUOTAS_REBUILDING 0x00000200 #define FILE_VC_VALID_MASK 0x000003ff +#define PHCM_APPLICATION_DEFAULT 0 +#define PHCM_DISGUISE_PLACEHOLDER 1 +#define PHCM_EXPOSE_PLACEHOLDERS 2 +#define PHCM_MAX 2 +#define PHCM_ERROR_INVALID_PARAMETER -1 +#define PHCM_ERROR_NO_TEB -2 + /* IOCTL code to impersonate client of named pipe. */ #define FSCTL_PIPE_DISCONNECT CTL_CODE(FILE_DEVICE_NAMED_PIPE, 1, \ @@ -1639,6 +1646,7 @@ extern "C" BOOLEAN); NTSTATUS RtlSetGroupSecurityDescriptor (PSECURITY_DESCRIPTOR, PSID, BOOLEAN); NTSTATUS RtlSetOwnerSecurityDescriptor (PSECURITY_DESCRIPTOR, PSID, BOOLEAN); + CHAR RtlSetProcessPlaceholderCompatibilityMode (CHAR); PUCHAR RtlSubAuthorityCountSid (PSID); PULONG RtlSubAuthoritySid (PSID, ULONG); ULONG RtlUnicodeStringToAnsiSize (PUNICODE_STRING); diff --git a/winsup/cygwin/local_includes/path.h b/winsup/cygwin/local_includes/path.h index d19721e0c..cd0cc8a41 100644 --- a/winsup/cygwin/local_includes/path.h +++ b/winsup/cygwin/local_includes/path.h @@ -23,6 +23,14 @@ has_attribute (DWORD attributes, DWORD attribs_to_test) && (attributes & attribs_to_test); } +extern inline bool +isoffline (DWORD attributes) +{ + return has_attribute (attributes, FILE_ATTRIBUTE_OFFLINE + | FILE_ATTRIBUTE_RECALL_ON_OPEN + | FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS); +} + enum executable_states { is_executable, @@ -236,6 +244,12 @@ class path_conv bool exists () const {return fileattr != INVALID_FILE_ATTRIBUTES;} bool has_attribute (DWORD x) const {return exists () && (fileattr & x);} int isdir () const {return has_attribute (FILE_ATTRIBUTE_DIRECTORY);} + bool isoffline () const + { + return has_attribute (FILE_ATTRIBUTE_OFFLINE + | FILE_ATTRIBUTE_RECALL_ON_OPEN + | FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS); + } executable_states exec_state () { extern int _check_for_executable; @@ -243,7 +257,7 @@ class path_conv return is_executable; if (mount_flags & MOUNT_NOTEXEC) return not_executable; - if (!_check_for_executable) + if (isoffline () || !_check_for_executable) return dont_care_if_executable; return dont_know_if_executable; } diff --git a/winsup/cygwin/local_includes/winlean.h b/winsup/cygwin/local_includes/winlean.h index 113b2c6b0..947109bde 100644 --- a/winsup/cygwin/local_includes/winlean.h +++ b/winsup/cygwin/local_includes/winlean.h @@ -97,6 +97,13 @@ details. */ #define FILE_SUPPORTS_GHOSTING 0x40000000 #endif +#ifndef FILE_ATTRIBUTE_RECALL_ON_OPEN +#define FILE_ATTRIBUTE_RECALL_ON_OPEN 0x00040000 +#endif +#ifndef FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS +#define FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS 0x00400000 +#endif + /* So-called "Microsoft Account" SIDs (S-1-11-...) have a netbios domain name "MicrosoftAccounts". The new "Application Container SIDs" (S-1-15-...) have a netbios domain name "APPLICATION PACKAGE AUTHORITY" diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc index b8e5746fd..c0d62e565 100644 --- a/winsup/cygwin/path.cc +++ b/winsup/cygwin/path.cc @@ -576,6 +576,7 @@ getfileattr (const char *path, bool caseinsensitive) /* path has to be always ab status = NtOpenFile (&dir, SYNCHRONIZE | FILE_LIST_DIRECTORY, &attr, &io, FILE_SHARE_VALID_FLAGS, FILE_SYNCHRONOUS_IO_NONALERT + | FILE_OPEN_NO_RECALL | FILE_OPEN_FOR_BACKUP_INTENT | FILE_DIRECTORY_FILE); if (NT_SUCCESS (status)) @@ -3191,7 +3192,8 @@ restart: } status = NtOpenFile (&h, READ_CONTROL | FILE_READ_ATTRIBUTES, &attr, &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_REPARSE_POINT + FILE_OPEN_NO_RECALL + | FILE_OPEN_REPARSE_POINT | FILE_OPEN_FOR_BACKUP_INTENT); debug_printf ("%y = NtOpenFile (no-EAs %S)", status, &upath); } @@ -3319,6 +3321,7 @@ restart: status = NtOpenFile (&dir, SYNCHRONIZE | FILE_LIST_DIRECTORY, &dattr, &io, FILE_SHARE_VALID_FLAGS, FILE_SYNCHRONOUS_IO_NONALERT + | FILE_OPEN_NO_RECALL | FILE_OPEN_FOR_BACKUP_INTENT | FILE_DIRECTORY_FILE); if (!NT_SUCCESS (status)) @@ -3408,7 +3411,11 @@ restart: directory using a relative path, symlink evaluation goes totally awry. We never want a virtual drive evaluated as symlink. */ if (upath.Length <= 14) - goto file_not_symlink; + goto file_not_symlink; + + /* Offline files, even if reparse points, are not symlinks. */ + if (isoffline (fileattr)) + goto file_not_symlink; /* Reparse points are potentially symlinks. This check must be performed before checking the SYSTEM attribute for sysfile @@ -3454,7 +3461,8 @@ restart: status = NtOpenFile (&sym_h, SYNCHRONIZE | GENERIC_READ, &attr, &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_FOR_BACKUP_INTENT + FILE_OPEN_NO_RECALL + | FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT); if (!NT_SUCCESS (status)) res = 0; @@ -3508,7 +3516,8 @@ restart: status = NtOpenFile (&sym_h, SYNCHRONIZE | GENERIC_READ, &attr, &io, FILE_SHARE_VALID_FLAGS, - FILE_OPEN_FOR_BACKUP_INTENT + FILE_OPEN_NO_RECALL + | FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT); if (!NT_SUCCESS (status))