From 9d69da4bdb1d546218d168b72f12ac8aa042e3d8 Mon Sep 17 00:00:00 2001 From: Jan Engelhardt Date: Sat, 28 Jul 2012 19:10:08 +0200 Subject: libxt_*limit: avoid division by zero It was possible to specify -A mychain -m hashlimit --hashlimit 600059/minute; this would convert to r->avg=0, which subsequently causes a division by zero when printing with -S mychain. 1. Avoid division by zero in print_rate by printing infinity instead. 2. Rewrite the test in parse_rate to properly reject too high rates. Signed-off-by: Jan Engelhardt --- extensions/libxt_hashlimit.c | 17 ++++++++++++----- extensions/libxt_limit.c | 17 ++++++++++++----- 2 files changed, 24 insertions(+), 10 deletions(-) (limited to 'extensions') diff --git a/extensions/libxt_hashlimit.c b/extensions/libxt_hashlimit.c index 37a31489..831345b7 100644 --- a/extensions/libxt_hashlimit.c +++ b/extensions/libxt_hashlimit.c @@ -10,6 +10,7 @@ * * Error corections by nmalykh@bilim.com (22.01.2005) */ +#include #include #include #include @@ -250,12 +251,13 @@ int parse_rate(const char *rate, uint32_t *val, struct hashlimit_mt_udata *ud) if (!r) return 0; - /* This would get mapped to infinite (1/day is minimum they - can specify, so we're ok at that end). */ - if (r / ud->mult > XT_HASHLIMIT_SCALE) - xtables_error(PARAMETER_PROBLEM, "Rate too fast \"%s\"\n", rate); - *val = XT_HASHLIMIT_SCALE * ud->mult / r; + if (*val == 0) + /* + * The rate maps to infinity. (1/day is the minimum they can + * specify, so we are ok at that end). + */ + xtables_error(PARAMETER_PROBLEM, "Rate too fast \"%s\"\n", rate); return 1; } @@ -434,6 +436,11 @@ static uint32_t print_rate(uint32_t period) { unsigned int i; + if (period == 0) { + printf(" %f", INFINITY); + return 0; + } + for (i = 1; i < ARRAY_SIZE(rates); ++i) if (period > rates[i].mult || rates[i].mult/period < rates[i].mult%period) diff --git a/extensions/libxt_limit.c b/extensions/libxt_limit.c index b15b02f2..023500cf 100644 --- a/extensions/libxt_limit.c +++ b/extensions/libxt_limit.c @@ -3,6 +3,7 @@ * Jérôme de Vivie * Hervé Eychenne */ +#include #include #include #include @@ -64,12 +65,13 @@ int parse_rate(const char *rate, uint32_t *val) if (!r) return 0; - /* This would get mapped to infinite (1/day is minimum they - can specify, so we're ok at that end). */ - if (r / mult > XT_LIMIT_SCALE) - xtables_error(PARAMETER_PROBLEM, "Rate too fast \"%s\"\n", rate); - *val = XT_LIMIT_SCALE * mult / r; + if (*val == 0) + /* + * The rate maps to infinity. (1/day is the minimum they can + * specify, so we are ok at that end). + */ + xtables_error(PARAMETER_PROBLEM, "Rate too fast \"%s\"\n", rate); return 1; } @@ -118,6 +120,11 @@ static void print_rate(uint32_t period) { unsigned int i; + if (period == 0) { + printf(" %f", INFINITY); + return; + } + for (i = 1; i < ARRAY_SIZE(rates); ++i) if (period > rates[i].mult || rates[i].mult/period < rates[i].mult%period) -- cgit v1.2.3