From 793c2bbc1ceac03ad785fc74a3a92db97e22b533 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Wed, 8 Jun 2022 11:56:03 +0200 Subject: [PATCH] mingw: be more informative when ownership check fails on FAT32 The FAT file system has no concept of ACLs. Therefore, it cannot store any ownership information anyway, and the `GetNamedSecurityInfoW()` call pretends that everything is owned "by the world". Let's special-case that scenario and tell the user what's going on, at least when they set `GIT_TEST_DEBUG_UNSAFE_DIRECTORIES`. This addresses https://github.com/git-for-windows/git/issues/3886 Signed-off-by: Johannes Schindelin --- compat/mingw.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/compat/mingw.c b/compat/mingw.c index ec21c4dc43..5af585098b 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -2674,6 +2674,22 @@ static PSID get_current_user_sid(void) return result; } +static int acls_supported(const char *path) +{ + size_t offset = offset_1st_component(path); + WCHAR wroot[MAX_PATH]; + DWORD file_system_flags; + + if (offset && + xutftowcs_path_ex(wroot, path, MAX_PATH, offset, + MAX_PATH, 0) > 0 && + GetVolumeInformationW(wroot, NULL, 0, NULL, NULL, + &file_system_flags, NULL, 0)) + return !!(file_system_flags & FILE_PERSISTENT_ACLS); + + return 0; +} + int is_path_owned_by_current_sid(const char *path) { WCHAR wpath[MAX_PATH]; @@ -2731,7 +2747,14 @@ int is_path_owned_by_current_sid(const char *path) * okay, too. */ result = 1; - else if (git_env_bool("GIT_TEST_DEBUG_UNSAFE_DIRECTORIES", 0)) { + else if (IsWellKnownSid(sid, WinWorldSid) && + git_env_bool("GIT_TEST_DEBUG_UNSAFE_DIRECTORIES", 0) && + !acls_supported(path)) { + /* + * On FAT32 volumes, ownership is not actually recorded. + */ + warning("'%s' is on a file system that does not record ownership", path); + } else if (git_env_bool("GIT_TEST_DEBUG_UNSAFE_DIRECTORIES", 0)) { LPSTR str1, str2, to_free1 = NULL, to_free2 = NULL; if (ConvertSidToStringSidA(sid, &str1))