string_helpers: add kstrdup_quotable

Handle allocating and escaping a string safe for logging.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This commit is contained in:
Kees Cook 2016-04-20 15:46:23 -07:00 committed by James Morris
parent 3c9d6296b7
commit b53f27e4fa
2 changed files with 30 additions and 0 deletions

View File

@ -68,4 +68,6 @@ static inline int string_escape_str_any_np(const char *src, char *dst,
return string_escape_str(src, dst, sz, ESCAPE_ANY_NP, only);
}
char *kstrdup_quotable(const char *src, gfp_t gfp);
#endif

View File

@ -10,6 +10,7 @@
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/string_helpers.h>
@ -534,3 +535,30 @@ 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);