From 90c4ae4e2c1da9f1eaf846136861af43d4c1ff34 Mon Sep 17 00:00:00 2001 From: Vishwanath Pai Date: Fri, 8 Sep 2017 01:38:58 -0400 Subject: netfilter: xt_hashlimit: fix build error caused by 64bit division 64bit division causes build/link errors on 32bit architectures. It prints out error messages like: ERROR: "__aeabi_uldivmod" [net/netfilter/xt_hashlimit.ko] undefined! The value of avg passed through by userspace in BYTE mode cannot exceed U32_MAX. Which means 64bit division in user2rate_bytes is unnecessary. To fix this I have changed the type of param 'user' to u32. Since anything greater than U32_MAX is an invalid input we error out in hashlimit_mt_check_common() when this is the case. Changes in v2: Making return type as u32 would cause an overflow for small values of 'user' (for example 2, 3 etc). To avoid this I bumped up 'r' to u64 again as well as the return type. This is OK since the variable that stores the result is u64. We still avoid 64bit division here since 'user' is u32. Fixes: bea74641e378 ("netfilter: xt_hashlimit: add rate match mode") Signed-off-by: Vishwanath Pai Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_hashlimit.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'net') diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 962ea4a63d9f..5da8746f7b88 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -35,6 +35,7 @@ #include #include #include +#include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte "); @@ -527,12 +528,12 @@ static u64 user2rate(u64 user) } } -static u64 user2rate_bytes(u64 user) +static u64 user2rate_bytes(u32 user) { u64 r; - r = user ? 0xFFFFFFFFULL / user : 0xFFFFFFFFULL; - r = (r - 1) << 4; + r = user ? U32_MAX / user : U32_MAX; + r = (r - 1) << XT_HASHLIMIT_BYTE_SHIFT; return r; } @@ -588,7 +589,8 @@ static void rateinfo_init(struct dsthash_ent *dh, dh->rateinfo.prev_window = 0; dh->rateinfo.current_rate = 0; if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) { - dh->rateinfo.rate = user2rate_bytes(hinfo->cfg.avg); + dh->rateinfo.rate = + user2rate_bytes((u32)hinfo->cfg.avg); if (hinfo->cfg.burst) dh->rateinfo.burst = hinfo->cfg.burst * dh->rateinfo.rate; @@ -870,7 +872,7 @@ static int hashlimit_mt_check_common(const struct xt_mtchk_param *par, /* Check for overflow. */ if (revision >= 3 && cfg->mode & XT_HASHLIMIT_RATE_MATCH) { - if (cfg->avg == 0) { + if (cfg->avg == 0 || cfg->avg > U32_MAX) { pr_info("hashlimit invalid rate\n"); return -ERANGE; } -- cgit