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authorJohannes Schindelin <johannes.schindelin@gmx.de>2019-12-21 22:05:01 (GMT)
committerJunio C Hamano <gitster@pobox.com>2019-12-22 00:09:07 (GMT)
commit4dc42c6c1867a52e22f1f04a1a247b5a7538b8af (patch)
tree2198d9e1995d36e5448de2dcf2c9063563f03803 /compat/mingw.c
parent98d9b23e90510c5acafa2ebc9463cc2293f40df0 (diff)
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mingw: refuse paths containing reserved names
There are a couple of reserved names that cannot be file names on Windows, such as `AUX`, `NUL`, etc. For an almost complete list, see https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file If one would try to create a directory named `NUL`, it would actually "succeed", i.e. the call would return success, but nothing would be created. Worse, even adding a file extension to the reserved name does not make it a valid file name. To understand the rationale behind that behavior, see https://devblogs.microsoft.com/oldnewthing/20031022-00/?p=42073 Let's just disallow them all. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'compat/mingw.c')
-rw-r--r--compat/mingw.c104
1 files changed, 90 insertions, 14 deletions
diff --git a/compat/mingw.c b/compat/mingw.c
index 03c4538..f482ecd 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -393,7 +393,7 @@ int mingw_mkdir(const char *path, int mode)
int ret;
wchar_t wpath[MAX_PATH];
- if (!is_valid_win32_path(path)) {
+ if (!is_valid_win32_path(path, 0)) {
errno = EINVAL;
return -1;
}
@@ -479,7 +479,7 @@ int mingw_open (const char *filename, int oflags, ...)
mode = va_arg(args, int);
va_end(args);
- if (!is_valid_win32_path(filename)) {
+ if (!is_valid_win32_path(filename, !create)) {
errno = create ? EINVAL : ENOENT;
return -1;
}
@@ -550,14 +550,13 @@ FILE *mingw_fopen (const char *filename, const char *otype)
int hide = needs_hiding(filename);
FILE *file;
wchar_t wfilename[MAX_PATH], wotype[4];
- if (!is_valid_win32_path(filename)) {
+ if (filename && !strcmp(filename, "/dev/null"))
+ wcscpy(wfilename, L"nul");
+ else if (!is_valid_win32_path(filename, 1)) {
int create = otype && strchr(otype, 'w');
errno = create ? EINVAL : ENOENT;
return NULL;
- }
- if (filename && !strcmp(filename, "/dev/null"))
- wcscpy(wfilename, L"nul");
- else if (xutftowcs_path(wfilename, filename) < 0)
+ } else if (xutftowcs_path(wfilename, filename) < 0)
return NULL;
if (xutftowcs(wotype, otype, ARRAY_SIZE(wotype)) < 0)
@@ -580,14 +579,13 @@ FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream)
int hide = needs_hiding(filename);
FILE *file;
wchar_t wfilename[MAX_PATH], wotype[4];
- if (!is_valid_win32_path(filename)) {
+ if (filename && !strcmp(filename, "/dev/null"))
+ wcscpy(wfilename, L"nul");
+ else if (!is_valid_win32_path(filename, 1)) {
int create = otype && strchr(otype, 'w');
errno = create ? EINVAL : ENOENT;
return NULL;
- }
- if (filename && !strcmp(filename, "/dev/null"))
- wcscpy(wfilename, L"nul");
- else if (xutftowcs_path(wfilename, filename) < 0)
+ } else if (xutftowcs_path(wfilename, filename) < 0)
return NULL;
if (xutftowcs(wotype, otype, ARRAY_SIZE(wotype)) < 0)
@@ -2412,14 +2410,16 @@ static void setup_windows_environment(void)
}
}
-int is_valid_win32_path(const char *path)
+int is_valid_win32_path(const char *path, int allow_literal_nul)
{
+ const char *p = path;
int preceding_space_or_period = 0, i = 0, periods = 0;
if (!protect_ntfs)
return 1;
skip_dos_drive_prefix((char **)&path);
+ goto segment_start;
for (;;) {
char c = *(path++);
@@ -2434,7 +2434,83 @@ int is_valid_win32_path(const char *path)
return 1;
i = periods = preceding_space_or_period = 0;
- continue;
+
+segment_start:
+ switch (*path) {
+ case 'a': case 'A': /* AUX */
+ if (((c = path[++i]) != 'u' && c != 'U') ||
+ ((c = path[++i]) != 'x' && c != 'X')) {
+not_a_reserved_name:
+ path += i;
+ continue;
+ }
+ break;
+ case 'c': case 'C': /* COM<N>, CON, CONIN$, CONOUT$ */
+ if ((c = path[++i]) != 'o' && c != 'O')
+ goto not_a_reserved_name;
+ c = path[++i];
+ if (c == 'm' || c == 'M') { /* COM<N> */
+ if (!isdigit(path[++i]))
+ goto not_a_reserved_name;
+ } else if (c == 'n' || c == 'N') { /* CON */
+ c = path[i + 1];
+ if ((c == 'i' || c == 'I') &&
+ ((c = path[i + 2]) == 'n' ||
+ c == 'N') &&
+ path[i + 3] == '$')
+ i += 3; /* CONIN$ */
+ else if ((c == 'o' || c == 'O') &&
+ ((c = path[i + 2]) == 'u' ||
+ c == 'U') &&
+ ((c = path[i + 3]) == 't' ||
+ c == 'T') &&
+ path[i + 4] == '$')
+ i += 4; /* CONOUT$ */
+ } else
+ goto not_a_reserved_name;
+ break;
+ case 'l': case 'L': /* LPT<N> */
+ if (((c = path[++i]) != 'p' && c != 'P') ||
+ ((c = path[++i]) != 't' && c != 'T') ||
+ !isdigit(path[++i]))
+ goto not_a_reserved_name;
+ break;
+ case 'n': case 'N': /* NUL */
+ if (((c = path[++i]) != 'u' && c != 'U') ||
+ ((c = path[++i]) != 'l' && c != 'L') ||
+ (allow_literal_nul &&
+ !path[i + 1] && p == path))
+ goto not_a_reserved_name;
+ break;
+ case 'p': case 'P': /* PRN */
+ if (((c = path[++i]) != 'r' && c != 'R') ||
+ ((c = path[++i]) != 'n' && c != 'N'))
+ goto not_a_reserved_name;
+ break;
+ default:
+ continue;
+ }
+
+ /*
+ * So far, this looks like a reserved name. Let's see
+ * whether it actually is one: trailing spaces, a file
+ * extension, or an NTFS Alternate Data Stream do not
+ * matter, the name is still reserved if any of those
+ * follow immediately after the actual name.
+ */
+ i++;
+ if (path[i] == ' ') {
+ preceding_space_or_period = 1;
+ while (path[++i] == ' ')
+ ; /* skip all spaces */
+ }
+
+ c = path[i];
+ if (c && c != '.' && c != ':' && c != '/' && c != '\\')
+ goto not_a_reserved_name;
+
+ /* contains reserved name */
+ return 0;
case '.':
periods++;
/* fallthru */