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Subject[PATCH] netfilter: xt_hashlimit: fix build error caused by 64bit division
Date
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.

This fix changes the size of both the param as well as return type on
user2rate_bytes 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.

Also fixed warning about const pointer conversion in cfg_copy().

Fixes: bea74641e378 ("netfilter: xt_hashlimit: add rate match mode")
Signed-off-by: Vishwanath Pai <vpai@akamai.com>
---
net/netfilter/xt_hashlimit.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 10d4823..1d818f1 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -35,6 +35,7 @@
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter/xt_hashlimit.h>
#include <linux/mutex.h>
+#include <linux/kernel.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
@@ -527,12 +528,12 @@ static u64 user2rate(u64 user)
}
}

-static u64 user2rate_bytes(u64 user)
+static u32 user2rate_bytes(u32 user)
{
- u64 r;
+ u32 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;
}
--
1.9.1
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