enable tun/tap/iptables

hc

2024-05-10 ee930fffee469d076998274a2ca55e13dc1efb67

 kernel/fs/binfmt_script.c
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..
@@ -1,3 +1,4 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  *  linux/fs/binfmt_script.c
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  *
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..
@@ -15,14 +16,14 @@
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 #include <linux/fs.h>
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17
 
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 static inline bool spacetab(char c) { return c == ' ' || c == '\t'; }
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-static inline char *next_non_spacetab(char *first, const char *last)
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+static inline const char *next_non_spacetab(const char *first, const char *last)
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 {
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 	for (; first <= last; first++)
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 		if (!spacetab(*first))
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 			return first;
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 	return NULL;
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 }
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-static inline char *next_terminator(char *first, const char *last)
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+static inline const char *next_terminator(const char *first, const char *last)
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 {
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 	for (; first <= last; first++)
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 		if (spacetab(*first) || !*first)
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..
@@ -32,28 +33,13 @@
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33
 
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 static int load_script(struct linux_binprm *bprm)
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 {
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-	const char *i_arg, *i_name;
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-	char *cp, *buf_end;
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+	const char *i_name, *i_sep, *i_arg, *i_end, *buf_end;
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 	struct file *file;
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 	int retval;
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 	/* Not ours to exec if we don't start with "#!". */
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 	if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
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 		return -ENOEXEC;
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-
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-	/*
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-	 * If the script filename will be inaccessible after exec, typically
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-	 * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
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-	 * up now (on the assumption that the interpreter will want to load
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-	 * this file).
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-	 */
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-	if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
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-		return -ENOENT;
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-
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-	/* Release since we are not mapping a binary into memory. */
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-	allow_write_access(bprm->file);
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-	fput(bprm->file);
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-	bprm->file = NULL;
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43
 
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 	/*
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 	 * This section handles parsing the #! line into separate
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@@ -70,39 +56,43 @@
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 	 * parse them on its own.
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 	 */
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 	buf_end = bprm->buf + sizeof(bprm->buf) - 1;
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-	cp = strnchr(bprm->buf, sizeof(bprm->buf), '\n');
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-	if (!cp) {
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-		cp = next_non_spacetab(bprm->buf + 2, buf_end);
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-		if (!cp)
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+	i_end = strnchr(bprm->buf, sizeof(bprm->buf), '\n');
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+	if (!i_end) {
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+		i_end = next_non_spacetab(bprm->buf + 2, buf_end);
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+		if (!i_end)
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 			return -ENOEXEC; /* Entire buf is spaces/tabs */
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 		/*
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 		 * If there is no later space/tab/NUL we must assume the
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 		 * interpreter path is truncated.
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 		 */
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-		if (!next_terminator(cp, buf_end))
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+		if (!next_terminator(i_end, buf_end))
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 			return -ENOEXEC;
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-		cp = buf_end;
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+		i_end = buf_end;
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 	}
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-	/* NUL-terminate the buffer and any trailing spaces/tabs. */
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-	*cp = '\0';
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-	while (cp > bprm->buf) {
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-		cp--;
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-		if ((*cp == ' ') || (*cp == '\t'))
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-			*cp = '\0';
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-		else
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-			break;
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-	}
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-	for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++);
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-	if (*cp == '\0')
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+	/* Trim any trailing spaces/tabs from i_end */
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+	while (spacetab(i_end[-1]))
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+		i_end--;
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+
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+	/* Skip over leading spaces/tabs */
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+	i_name = next_non_spacetab(bprm->buf+2, i_end);
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+	if (!i_name || (i_name == i_end))
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 		return -ENOEXEC; /* No interpreter name found */
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-	i_name = cp;
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+
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+	/* Is there an optional argument? */
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 	i_arg = NULL;
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-	for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)
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-		/* nothing */ ;
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-	while ((*cp == ' ') || (*cp == '\t'))
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-		*cp++ = '\0';
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-	if (*cp)
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-		i_arg = cp;
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+	i_sep = next_terminator(i_name, i_end);
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+	if (i_sep && (*i_sep != '\0'))
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+		i_arg = next_non_spacetab(i_sep, i_end);
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+
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+	/*
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+	 * If the script filename will be inaccessible after exec, typically
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+	 * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
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+	 * up now (on the assumption that the interpreter will want to load
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+	 * this file).
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+	 */
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+	if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
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+		return -ENOENT;
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+
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 	/*
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 	 * OK, we've parsed out the interpreter name and
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 	 * (optional) argument.
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@@ -116,17 +106,19 @@
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 	retval = remove_arg_zero(bprm);
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 	if (retval)
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 		return retval;
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-	retval = copy_strings_kernel(1, &bprm->interp, bprm);
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+	retval = copy_string_kernel(bprm->interp, bprm);
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 	if (retval < 0)
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 		return retval;
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 	bprm->argc++;
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+	*((char *)i_end) = '\0';
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 	if (i_arg) {
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-		retval = copy_strings_kernel(1, &i_arg, bprm);
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+		*((char *)i_sep) = '\0';
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+		retval = copy_string_kernel(i_arg, bprm);
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 		if (retval < 0)
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 			return retval;
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 		bprm->argc++;
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 	}
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-	retval = copy_strings_kernel(1, &i_name, bprm);
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+	retval = copy_string_kernel(i_name, bprm);
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 	if (retval)
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 		return retval;
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 	bprm->argc++;
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@@ -141,11 +133,8 @@
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 	if (IS_ERR(file))
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 		return PTR_ERR(file);
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-	bprm->file = file;
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-	retval = prepare_binprm(bprm);
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-	if (retval < 0)
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-		return retval;
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-	return search_binary_handler(bprm);
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+	bprm->interpreter = file;
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+	return 0;
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 }
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 static struct linux_binfmt script_format = {