The patch titled
Subject: lib: bitmap_parselist: rework input string parser
has been added to the -mm tree. Its filename is
bitmap_parselist-rework-input-string-parser.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/bitmap_parselist-rework-input-string-parser.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/bitmap_parselist-rework-input-string-parser.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Yury Norov <yury.norov@xxxxxxxxx>
Subject: lib: bitmap_parselist: rework input string parser
The requirement for this rework is to keep the __bitmap_parselist()
copy-less and single-pass but make it more readable and maintainable by
splitting into logical parts and removing explicit nested cycles and
opaque local variables.
__bitmap_parselist() can parse userspace inputs and therefore we cannot
use simple_strtoul() to parse numbers.
Link: http://lkml.kernel.org/r/20190325210748.6571-4-ynorov@xxxxxxxxxxx
Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/bitmap.c | 251 +++++++++++++++++++++++++++++--------------------
1 file changed, 150 insertions(+), 101 deletions(-)
--- a/lib/bitmap.c~bitmap_parselist-rework-input-string-parser
+++ a/lib/bitmap.c
@@ -513,6 +513,139 @@ static int bitmap_check_region(const str
return 0;
}
+static long get_char(char *c, const char *str, int is_user)
+{
+ if (unlikely(is_user))
+ return __get_user(*c, (const char __force __user *)str);
+
+ *c = *str;
+ return 0;
+}
+
+static const char *bitmap_getnum(unsigned int *num, const char *str,
+ const char *const end, int is_user)
+{
+ unsigned int n = 0;
+ const char *_str;
+ long ret;
+ char c;
+
+ for (_str = str, *num = 0; _str <= end; _str++) {
+ ret = get_char(&c, _str, is_user);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (!isdigit(c)) {
+ if (_str == str)
+ return ERR_PTR(-EINVAL);
+
+ return _str;
+ }
+
+ *num = *num * 10 + (c - '0');
+ if (*num < n)
+ return ERR_PTR(-EOVERFLOW);
+
+ n = *num;
+ }
+
+ return _str;
+}
+
+static const char *bitmap_find_region(const char *str,
+ const char *const end, int is_user)
+{
+ long ret;
+ char c;
+
+ for (; str <= end; str++) {
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return ERR_PTR(ret);
+
+ /* Unexpected end of line. */
+ if (c == 0 || c == '\n')
+ return NULL;
+
+ /*
+ * The format allows commas and whitespases
+ * at the beginning of the region, so skip it.
+ */
+ if (!isspace(c) && c != ',')
+ break;
+ }
+
+ return str <= end ? str : NULL;
+}
+
+static const char *bitmap_parse_region(struct region *r, const char *str,
+ const char *const end, int is_user)
+{
+ long ret;
+ char c;
+
+ str = bitmap_getnum(&r->start, str, end, is_user);
+ if (IS_ERR(str))
+ return str;
+
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return (char *)ret;
+
+ if (c == 0 || c == '\n') {
+ str = end + 1;
+ goto no_end;
+ }
+
+ if (isspace(c) || c == ',')
+ goto no_end;
+
+ if (c != '-')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(&r->end, str + 1, end, is_user);
+ if (IS_ERR(str))
+ return str;
+
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (c == 0 || c == '\n') {
+ str = end + 1;
+ goto no_pattern;
+ }
+
+ if (isspace(c) || c == ',')
+ goto no_pattern;
+
+ if (c != ':')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(&r->off, str + 1, end, is_user);
+ if (IS_ERR(str))
+ return str;
+
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return (char *)ret;
+
+ if (c != '/')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(&r->grlen, str + 1, end, is_user);
+
+ return str;
+
+no_end:
+ r->end = r->start;
+no_pattern:
+ r->off = r->end + 1;
+ r->grlen = r->end + 1;
+
+ return str;
+}
+
/**
* __bitmap_parselist - convert list format ASCII string to bitmap
* @buf: read nul-terminated user string from this buffer
@@ -534,113 +667,28 @@ static int bitmap_check_region(const str
*
* Returns: 0 on success, -errno on invalid input strings. Error values:
*
- * - ``-EINVAL``: second number in range smaller than first
+ * - ``-EINVAL``: wrong region format
* - ``-EINVAL``: invalid character in string
* - ``-ERANGE``: bit number specified too large for mask
+ * - ``-EOVERFLOW``: integer overflow in the input parameters
*/
-static int __bitmap_parselist(const char *buf, unsigned int buflen,
+static int __bitmap_parselist(const char *buf, const char *const end,
int is_user, unsigned long *maskp,
int nmaskbits)
{
- unsigned int a, b, old_a, old_b;
- unsigned int group_size, used_size;
- int c, old_c, totaldigits, ndigits;
- const char __user __force *ubuf = (const char __user __force *)buf;
- int at_start, in_range, in_partial_range, ret;
struct region r;
+ long ret;
- totaldigits = c = 0;
- old_a = old_b = 0;
- group_size = used_size = 0;
bitmap_zero(maskp, nmaskbits);
- do {
- at_start = 1;
- in_range = 0;
- in_partial_range = 0;
- a = b = 0;
- ndigits = totaldigits;
-
- /* Get the next cpu# or a range of cpu#'s */
- while (buflen) {
- old_c = c;
- if (is_user) {
- if (__get_user(c, ubuf++))
- return -EFAULT;
- } else
- c = *buf++;
- buflen--;
- if (isspace(c))
- continue;
-
- /* 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 == '/') {
- used_size = a;
- at_start = 1;
- in_range = 0;
- a = b = 0;
- continue;
- }
-
- if (c == ':') {
- old_a = a;
- old_b = b;
- at_start = 1;
- in_range = 0;
- in_partial_range = 1;
- a = b = 0;
- continue;
- }
-
- if (c == '-') {
- if (at_start || in_range)
- return -EINVAL;
- b = 0;
- in_range = 1;
- at_start = 1;
- continue;
- }
-
- if (!isdigit(c))
- return -EINVAL;
-
- b = b * 10 + (c - '0');
- if (!in_range)
- a = b;
- at_start = 0;
- totaldigits++;
- }
- if (ndigits == totaldigits)
- continue;
- if (in_partial_range) {
- group_size = a;
- a = old_a;
- b = old_b;
- old_a = old_b = 0;
- } else {
- used_size = group_size = b - a + 1;
- }
- /* if no digit is after '-', it's wrong*/
- if (at_start && in_range)
- return -EINVAL;
-
- r.start = a;
- r.off = used_size;
- r.grlen = group_size;
- r.end = b;
+
+ while (buf && buf <= end) {
+ buf = bitmap_find_region(buf, end, is_user);
+ if (buf == NULL)
+ return 0;
+
+ buf = bitmap_parse_region(&r, buf, end, is_user);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
ret = bitmap_check_region(&r);
if (ret)
@@ -649,14 +697,14 @@ static int __bitmap_parselist(const char
ret = bitmap_set_region(&r, maskp, nmaskbits);
if (ret)
return ret;
+ }
- } while (buflen && c == ',');
return 0;
}
int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
{
- return __bitmap_parselist(bp, UINT_MAX, 0, maskp, nmaskbits);
+ return __bitmap_parselist(bp, (char *)SIZE_MAX, 0, maskp, nmaskbits);
}
EXPORT_SYMBOL(bitmap_parselist);
@@ -683,7 +731,8 @@ int bitmap_parselist_user(const char __u
if (!access_ok(ubuf, ulen))
return -EFAULT;
return __bitmap_parselist((const char __force *)ubuf,
- ulen, 1, maskp, nmaskbits);
+ (const char __force *)ubuf + ulen - 1,
+ 1, maskp, nmaskbits);
}
EXPORT_SYMBOL(bitmap_parselist_user);
_
Patches currently in -mm which might be from yury.norov@xxxxxxxxx are
bitmap_parselist-dont-calculate-length-of-the-input-string.patch
bitmap_parselist-move-non-parser-logic-to-helpers.patch
bitmap_parselist-rework-input-string-parser.patch
lib-test_bitmap-switch-test_bitmap_parselist-to-ktime_get.patch
lib-test_bitmap-add-testcases-for-bitmap_parselist.patch
lib-test_bitmap-add-tests-for-bitmap_parselist_user.patch
