Commit 53809751 authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
Browse files

sscanf: don't ignore field widths for numeric conversions 



This is another step towards better standard conformance.  Rather than
adding a local buffer to store the specified portion of the string (with
the need to enforce an arbitrary maximum supported width to limit the
buffer size), do a maximum width conversion and then drop as much of it as
is necessary to meet the caller's request.

Also fail on negative field widths.

Uses the deprecated simple_strto*() functions because kstrtoXX() fail on
non-zero terminated strings.

Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 375da3a7

lib/vsprintf.c

+53 −43
Original line number Diff line number Diff line
@@ -23,12 +23,12 @@ 
#include <linux/ctype.h>

#include <linux/kernel.h>

#include <linux/kallsyms.h>

#include <linux/math64.h>

#include <linux/uaccess.h>

#include <linux/ioport.h>

#include <net/addrconf.h>



#include <asm/page.h>		/* for PAGE_SIZE */

#include <asm/div64.h>

#include <asm/sections.h>	/* for dereference_function_descriptor() */



#include "kstrtox.h"
@@ -2016,7 +2016,11 @@ int vsscanf(const char *buf, const char *fmt, va_list args) 
	char digit;

	int num = 0;

	u8 qualifier;

	u8 base;

	unsigned int base;

	union {

		long long s;

		unsigned long long u;

	} val;

	s16 field_width;

	bool is_sign;
@@ -2056,8 +2060,11 @@ int vsscanf(const char *buf, const char *fmt, va_list args) 


		/* get field width */

		field_width = -1;

		if (isdigit(*fmt))

		if (isdigit(*fmt)) {

			field_width = skip_atoi(&fmt);

			if (field_width <= 0)

				break;

		}



		/* get conversion qualifier */

		qualifier = -1;
@@ -2157,58 +2164,61 @@ int vsscanf(const char *buf, const char *fmt, va_list args) 
		    || (base == 0 && !isdigit(digit)))

			break;



		if (is_sign)

			val.s = qualifier != 'L' ?

				simple_strtol(str, &next, base) :

				simple_strtoll(str, &next, base);

		else

			val.u = qualifier != 'L' ?

				simple_strtoul(str, &next, base) :

				simple_strtoull(str, &next, base);



		if (field_width > 0 && next - str > field_width) {

			if (base == 0)

				_parse_integer_fixup_radix(str, &base);

			while (next - str > field_width) {

				if (is_sign)

					val.s = div_s64(val.s, base);

				else

					val.u = div_u64(val.u, base);

				--next;

			}

		}



		switch (qualifier) {

		case 'H':	/* that's 'hh' in format */

			if (is_sign) {

				signed char *s = (signed char *)va_arg(args, signed char *);

				*s = (signed char)simple_strtol(str, &next, base);

			} else {

				unsigned char *s = (unsigned char *)va_arg(args, unsigned char *);

				*s = (unsigned char)simple_strtoul(str, &next, base);

			}

			if (is_sign)

				*va_arg(args, signed char *) = val.s;

			else

				*va_arg(args, unsigned char *) = val.u;

			break;

		case 'h':

			if (is_sign) {

				short *s = (short *)va_arg(args, short *);

				*s = (short)simple_strtol(str, &next, base);

			} else {

				unsigned short *s = (unsigned short *)va_arg(args, unsigned short *);

				*s = (unsigned short)simple_strtoul(str, &next, base);

			}

			if (is_sign)

				*va_arg(args, short *) = val.s;

			else

				*va_arg(args, unsigned short *) = val.u;

			break;

		case 'l':

			if (is_sign) {

				long *l = (long *)va_arg(args, long *);

				*l = simple_strtol(str, &next, base);

			} else {

				unsigned long *l = (unsigned long *)va_arg(args, unsigned long *);

				*l = simple_strtoul(str, &next, base);

			}

			if (is_sign)

				*va_arg(args, long *) = val.s;

			else

				*va_arg(args, unsigned long *) = val.u;

			break;

		case 'L':

			if (is_sign) {

				long long *l = (long long *)va_arg(args, long long *);

				*l = simple_strtoll(str, &next, base);

			} else {

				unsigned long long *l = (unsigned long long *)va_arg(args, unsigned long long *);

				*l = simple_strtoull(str, &next, base);

			}

			if (is_sign)

				*va_arg(args, long long *) = val.s;

			else

				*va_arg(args, unsigned long long *) = val.u;

			break;

		case 'Z':

		case 'z':

		{

			size_t *s = (size_t *)va_arg(args, size_t *);

			*s = (size_t)simple_strtoul(str, &next, base);

		}

			*va_arg(args, size_t *) = val.u;

			break;

		default:

			if (is_sign) {

				int *i = (int *)va_arg(args, int *);

				*i = (int)simple_strtol(str, &next, base);

			} else {

				unsigned int *i = (unsigned int *)va_arg(args, unsigned int*);

				*i = (unsigned int)simple_strtoul(str, &next, base);

			}

			if (is_sign)

				*va_arg(args, int *) = val.s;

			else

				*va_arg(args, unsigned int *) = val.u;

			break;

		}

		num++;

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