1 files changed, 92 insertions, 0 deletions

diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 5c88204b6f1f..ecaac2c0526f 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -10,6 +10,10 @@
 #include <linux/export.h>
 #include <linux/ctype.h>
 #include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/limits.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/string_helpers.h>
 
@@ -534,3 +538,91 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 	return p - dst;
 }
 EXPORT_SYMBOL(string_escape_mem);
+
+/*
+ * Return an allocated string that has been escaped of special characters
+ * and double quotes, making it safe to log in quotes.
+ */
+char *kstrdup_quotable(const char *src, gfp_t gfp)
+{
+	size_t slen, dlen;
+	char *dst;
+	const int flags = ESCAPE_HEX;
+	const char esc[] = "\f\n\r\t\v\a\e\\\"";
+
+	if (!src)
+		return NULL;
+	slen = strlen(src);
+
+	dlen = string_escape_mem(src, slen, NULL, 0, flags, esc);
+	dst = kmalloc(dlen + 1, gfp);
+	if (!dst)
+		return NULL;
+
+	WARN_ON(string_escape_mem(src, slen, dst, dlen, flags, esc) != dlen);
+	dst[dlen] = '\0';
+
+	return dst;
+}
+EXPORT_SYMBOL_GPL(kstrdup_quotable);
+
+/*
+ * Returns allocated NULL-terminated string containing process
+ * command line, with inter-argument NULLs replaced with spaces,
+ * and other special characters escaped.
+ */
+char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)
+{
+	char *buffer, *quoted;
+	int i, res;
+
+	buffer = kmalloc(PAGE_SIZE, GFP_TEMPORARY);
+	if (!buffer)
+		return NULL;
+
+	res = get_cmdline(task, buffer, PAGE_SIZE - 1);
+	buffer[res] = '\0';
+
+	/* Collapse trailing NULLs, leave res pointing to last non-NULL. */
+	while (--res >= 0 && buffer[res] == '\0')
+		;
+
+	/* Replace inter-argument NULLs. */
+	for (i = 0; i <= res; i++)
+		if (buffer[i] == '\0')
+			buffer[i] = ' ';
+
+	/* Make sure result is printable. */
+	quoted = kstrdup_quotable(buffer, gfp);
+	kfree(buffer);
+	return quoted;
+}
+EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline);
+
+/*
+ * Returns allocated NULL-terminated string containing pathname,
+ * with special characters escaped, able to be safely logged. If
+ * there is an error, the leading character will be "<".
+ */
+char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
+{
+	char *temp, *pathname;
+
+	if (!file)
+		return kstrdup("<unknown>", gfp);
+
+	/* We add 11 spaces for ' (deleted)' to be appended */
+	temp = kmalloc(PATH_MAX + 11, GFP_TEMPORARY);
+	if (!temp)
+		return kstrdup("<no_memory>", gfp);
+
+	pathname = file_path(file, temp, PATH_MAX + 11);
+	if (IS_ERR(pathname))
+		pathname = kstrdup("<too_long>", gfp);
+	else
+		pathname = kstrdup_quotable(pathname, gfp);
+
+	kfree(temp);
+	return pathname;
+}
+EXPORT_SYMBOL_GPL(kstrdup_quotable_file);