From 9bf98f168b7b004c94c766a6989071e0f858def3 Mon Sep 17 00:00:00 2001 From: Pan Xinhui Date: Wed, 9 Sep 2015 15:37:08 -0700 Subject: [PATCH] lib/bitmap.c: bitmap_parselist can accept string with whitespaces on head or tail In __bitmap_parselist we can accept whitespaces on head or tail during every parsing procedure. If input has valid ranges, there is no reason to reject the user. For example, bitmap_parselist(" 1-3, 5, ", &mask, nmaskbits). After separating the string, we get " 1-3", " 5", and " ". It's possible and reasonable to accept such string as long as the parsing result is correct. Signed-off-by: Pan Xinhui Cc: Yury Norov Cc: Chris Metcalf Cc: Rasmus Villemoes Cc: Sudeep Holla Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/bitmap.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index f549176e9250..814814397cce 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -506,7 +506,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, int nmaskbits) { unsigned a, b; - int c, old_c, totaldigits; + int c, old_c, totaldigits, ndigits; const char __user __force *ubuf = (const char __user __force *)buf; int at_start, in_range; @@ -516,6 +516,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, at_start = 1; in_range = 0; a = b = 0; + ndigits = totaldigits; /* Get the next cpu# or a range of cpu#'s */ while (buflen) { @@ -529,17 +530,20 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, if (isspace(c)) continue; - /* - * If the last character was a space and the current - * character isn't '\0', we've got embedded whitespace. - * This is a no-no, so throw an error. - */ - if (totaldigits && c && isspace(old_c)) - return -EINVAL; - /* A '\0' or a ',' signal the end of a cpu# or range */ if (c == '\0' || c == ',') break; + /* + * whitespaces between digits are not allowed, + * but it's ok if whitespaces are on head or tail. + * when old_c is whilespace, + * if totaldigits == ndigits, whitespace is on head. + * if whitespace is on tail, it should not run here. + * as c was ',' or '\0', + * the last code line has broken the current loop. + */ + if ((totaldigits != ndigits) && isspace(old_c)) + return -EINVAL; if (c == '-') { if (at_start || in_range) @@ -559,6 +563,8 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, at_start = 0; totaldigits++; } + if (ndigits == totaldigits) + continue; /* if no digit is after '-', it's wrong*/ if (at_start && in_range) return -EINVAL; @@ -566,11 +572,9 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, return -EINVAL; if (b >= nmaskbits) return -ERANGE; - if (!at_start) { - while (a <= b) { - set_bit(a, maskp); - a++; - } + while (a <= b) { + set_bit(a, maskp); + a++; } } while (buflen && c == ','); return 0; -- 2.34.1