From d89a3f7335bb5d9e572ecc287b300161200364eb Mon Sep 17 00:00:00 2001 From: Kees Cook <keescook@chromium.org> Date: Wed, 9 Sep 2015 15:37:14 -0700 Subject: [PATCH] lib/string_helpers: clarify esc arg in string_escape_mem The esc argument is used to reduce which characters will be escaped. For example, using " " with ESCAPE_SPACE will not produce any escaped spaces. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Mathias Krause <minipli@googlemail.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- lib/string_helpers.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/lib/string_helpers.c b/lib/string_helpers.c index c98ae818eb4ee..0a307a97d489c 100644 --- a/lib/string_helpers.c +++ b/lib/string_helpers.c @@ -410,7 +410,7 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * @dst: destination buffer (escaped) * @osz: destination buffer size * @flags: combination of the flags (bitwise OR): - * %ESCAPE_SPACE: + * %ESCAPE_SPACE: (special white space, not space itself) * '\f' - form feed * '\n' - new line * '\r' - carriage return @@ -432,8 +432,10 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * all previous together * %ESCAPE_HEX: * '\xHH' - byte with hexadecimal value HH (2 digits) - * @esc: NULL-terminated string of characters any of which, if found in - * the source, has to be escaped + * @esc: NULL-terminated string containing characters used to limit + * the selected escape class. If characters are included in @esc + * that would not normally be escaped by the classes selected + * in @flags, they will be copied to @dst unescaped. * * Description: * The process of escaping byte buffer includes several parts. They are applied @@ -441,7 +443,7 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * 1. The character is matched to the printable class, if asked, and in * case of match it passes through to the output. * 2. The character is not matched to the one from @esc string and thus - * must go as is to the output. + * must go as-is to the output. * 3. The character is checked if it falls into the class given by @flags. * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any * character. Note that they actually can't go together, otherwise -- GitLab