From 6e7ad1e4c22e7038975ba37c7413374fe566b064 Mon Sep 17 00:00:00 2001 From: Carlo Marcelo Arenas Belón Date: Sat, 27 Nov 2021 10:15:32 +0000 Subject: mingw: avoid fallback for {local,gm}time_r() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit mingw-w64's pthread_unistd.h had a bug that mistakenly (because there is no support for the *lockfile() functions required[1]) defined _POSIX_THREAD_SAFE_FUNCTIONS and that was being worked around since 3ecd153a3b (compat/mingw: support MSys2-based MinGW build, 2016-01-14). The bug was fixed in winphtreads, but as a side effect, leaves the reentrant functions from time.h no longer visible and therefore breaks the build. Since the intention all along was to avoid using the fallback functions, formalize the use of POSIX by setting the corresponding feature flag and compile out the implementation for the fallback functions. [1] https://unix.org/whitepapers/reentrant.html Signed-off-by: Carlo Marcelo Arenas Belón Acked-by: Johannes Schindelin Signed-off-by: Junio C Hamano --- git-compat-util.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'git-compat-util.h') diff --git a/git-compat-util.h b/git-compat-util.h index 7d3db43f11..3da9f975e2 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -127,7 +127,9 @@ /* Approximation of the length of the decimal representation of this type. */ #define decimal_length(x) ((int)(sizeof(x) * 2.56 + 0.5) + 1) -#if defined(__sun__) +#ifdef __MINGW64__ +#define _POSIX_C_SOURCE 1 +#elif defined(__sun__) /* * On Solaris, when _XOPEN_EXTENDED is set, its header file * forces the programs to be XPG4v2, defeating any _XOPEN_SOURCE -- cgit v1.2.3 From bdc77d1d685be9c10b88abb281a42bc620548595 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Wed, 2 Mar 2022 11:06:24 +0100 Subject: Add a function to determine whether a path is owned by the current user This function will be used in the next commit to prevent `setup_git_directory()` from discovering a repository in a directory that is owned by someone other than the current user. Note: We cannot simply use `st.st_uid` on Windows just like we do on Linux and other Unix-like platforms: according to https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/stat-functions this field is always zero on Windows (because Windows' idea of a user ID does not fit into a single numerical value). Therefore, we have to do something a little involved to replicate the same functionality there. Also note: On Windows, a user's home directory is not actually owned by said user, but by the administrator. For all practical purposes, it is under the user's control, though, therefore we pretend that it is owned by the user. Signed-off-by: Johannes Schindelin --- compat/mingw.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ compat/mingw.h | 7 +++++ git-compat-util.h | 12 ++++++++ 3 files changed, 106 insertions(+) (limited to 'git-compat-util.h') diff --git a/compat/mingw.c b/compat/mingw.c index abb4d26ce9..38ac35913d 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -1,5 +1,6 @@ #include "../git-compat-util.h" #include "win32.h" +#include #include #include #include "../strbuf.h" @@ -2601,6 +2602,92 @@ static void setup_windows_environment(void) } } +static PSID get_current_user_sid(void) +{ + HANDLE token; + DWORD len = 0; + PSID result = NULL; + + if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &token)) + return NULL; + + if (!GetTokenInformation(token, TokenUser, NULL, 0, &len)) { + TOKEN_USER *info = xmalloc((size_t)len); + if (GetTokenInformation(token, TokenUser, info, len, &len)) { + len = GetLengthSid(info->User.Sid); + result = xmalloc(len); + if (!CopySid(len, result, info->User.Sid)) { + error(_("failed to copy SID (%ld)"), + GetLastError()); + FREE_AND_NULL(result); + } + } + FREE_AND_NULL(info); + } + CloseHandle(token); + + return result; +} + +int is_path_owned_by_current_sid(const char *path) +{ + WCHAR wpath[MAX_PATH]; + PSID sid = NULL; + PSECURITY_DESCRIPTOR descriptor = NULL; + DWORD err; + + static wchar_t home[MAX_PATH]; + + int result = 0; + + if (xutftowcs_path(wpath, path) < 0) + return 0; + + /* + * On Windows, the home directory is owned by the administrator, but for + * all practical purposes, it belongs to the user. Do pretend that it is + * owned by the user. + */ + if (!*home) { + DWORD size = ARRAY_SIZE(home); + DWORD len = GetEnvironmentVariableW(L"HOME", home, size); + if (!len || len > size) + wcscpy(home, L"::N/A::"); + } + if (!wcsicmp(wpath, home)) + return 1; + + /* Get the owner SID */ + err = GetNamedSecurityInfoW(wpath, SE_FILE_OBJECT, + OWNER_SECURITY_INFORMATION | + DACL_SECURITY_INFORMATION, + &sid, NULL, NULL, NULL, &descriptor); + + if (err != ERROR_SUCCESS) + error(_("failed to get owner for '%s' (%ld)"), path, err); + else if (sid && IsValidSid(sid)) { + /* Now, verify that the SID matches the current user's */ + static PSID current_user_sid; + + if (!current_user_sid) + current_user_sid = get_current_user_sid(); + + if (current_user_sid && + IsValidSid(current_user_sid) && + EqualSid(sid, current_user_sid)) + result = 1; + } + + /* + * We can release the security descriptor struct only now because `sid` + * actually points into this struct. + */ + if (descriptor) + LocalFree(descriptor); + + return result; +} + int is_valid_win32_path(const char *path, int allow_literal_nul) { const char *p = path; diff --git a/compat/mingw.h b/compat/mingw.h index af8eddd73e..f6bab548f4 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -452,6 +452,13 @@ char *mingw_query_user_email(void); #include #endif +/** + * Verifies that the specified path is owned by the user running the + * current process. + */ +int is_path_owned_by_current_sid(const char *path); +#define is_path_owned_by_current_user is_path_owned_by_current_sid + /** * Verifies that the given path is a valid one on Windows. * diff --git a/git-compat-util.h b/git-compat-util.h index 3da9f975e2..63ba89dd31 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -392,6 +392,18 @@ static inline int git_offset_1st_component(const char *path) #define is_valid_path(path) 1 #endif +#ifndef is_path_owned_by_current_user +static inline int is_path_owned_by_current_uid(const char *path) +{ + struct stat st; + if (lstat(path, &st)) + return 0; + return st.st_uid == geteuid(); +} + +#define is_path_owned_by_current_user is_path_owned_by_current_uid +#endif + #ifndef find_last_dir_sep static inline char *git_find_last_dir_sep(const char *path) { -- cgit v1.2.3