Date: Sat, 15 Aug 2015 08:42:33 +0000 (UTC) From: Ed Schouten <ed@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r286798 - head/sys/teken Message-ID: <201508150842.t7F8gXKf058556@repo.freebsd.org>
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Author: ed Date: Sat Aug 15 08:42:33 2015 New Revision: 286798 URL: https://svnweb.freebsd.org/changeset/base/286798 Log: Stop parsing digits if the value already exceeds USHRT_MAX. There is no need for us to support parsing values that are larger than the maximum terminal window size. In this case that would be the maximum of unsigned short. The problem with parsing larger values is that they can cause integer overflows when adjusting the cursor position, leading to all sorts of failing assertions. PR: 202326 Reported by: kcwu csie org MFC after: 1 month Modified: head/sys/teken/teken.c Modified: head/sys/teken/teken.c ============================================================================== --- head/sys/teken/teken.c Sat Aug 15 08:29:13 2015 (r286797) +++ head/sys/teken/teken.c Sat Aug 15 08:42:33 2015 (r286798) @@ -29,12 +29,14 @@ #include <sys/cdefs.h> #if defined(__FreeBSD__) && defined(_KERNEL) #include <sys/param.h> +#include <sys/limits.h> #include <sys/lock.h> #include <sys/systm.h> #define teken_assert(x) MPASS(x) #else /* !(__FreeBSD__ && _KERNEL) */ #include <sys/types.h> #include <assert.h> +#include <limits.h> #include <stdint.h> #include <stdio.h> #include <string.h> @@ -405,18 +407,21 @@ teken_state_numbers(teken_t *t, teken_ch teken_assert(t->t_curnum < T_NUMSIZE); if (c >= '0' && c <= '9') { - /* - * Don't do math with the default value of 1 when a - * custom number is inserted. - */ if (t->t_stateflags & TS_FIRSTDIGIT) { + /* First digit. */ t->t_stateflags &= ~TS_FIRSTDIGIT; - t->t_nums[t->t_curnum] = 0; - } else { - t->t_nums[t->t_curnum] *= 10; + t->t_nums[t->t_curnum] = c - '0'; + } else if (t->t_nums[t->t_curnum] < USHRT_MAX) { + /* + * Screen positions are stored as unsigned + * shorts. There is no need to continue parsing + * input once the value exceeds USHRT_MAX. It + * would only allow for integer overflows when + * performing arithmetic on the cursor position. + */ + t->t_nums[t->t_curnum] = + t->t_nums[t->t_curnum] * 10 + c - '0'; } - - t->t_nums[t->t_curnum] += c - '0'; return (1); } else if (c == ';') { if (t->t_stateflags & TS_FIRSTDIGIT)
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