[PATCH 5.4 017/154] ipvs: prevent integer overflow in do_ip_vs_get_ctl()

Greg Kroah-Hartman
2025-04-08T12:02:57Z

From: Dan Carpenter <dan.carpenter@linaro.org>

[ Upstream commit 80b78c39eb86e6b55f56363b709eb817527da5aa ]

The get->num_services variable is an unsigned int which is controlled by
the user. The struct_size() function ensures that the size calculation
does not overflow an unsigned long, however, we are saving the result to
an int so the calculation can overflow.

Both "len" and "get->num_services" come from the user. This check is
just a sanity check to help the user and ensure they are using the API
correctly. An integer overflow here is not a big deal. This has no
security impact.

Save the result from struct_size() type size_t to fix this integer
overflow bug.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/ipvs/ip_vs_ctl.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 2bc82dabfe3b8..dcce6aaac970e 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2809,12 +2809,12 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
case IP_VS_SO_GET_SERVICES:
{
struct ip_vs_get_services *get;
- int size;
+ size_t size;

get = (struct ip_vs_get_services *)arg;
size = struct_size(get, entrytable, get->num_services);
if (*len != size) {
- pr_err("length: %u != %u\n", *len, size);
+ pr_err("length: %u != %zu\n", *len, size);
ret = -EINVAL;
goto out;
}
@@ -2850,12 +2850,12 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
case IP_VS_SO_GET_DESTS:
{
struct ip_vs_get_dests *get;
- int size;
+ size_t size;

get = (struct ip_vs_get_dests *)arg;
size = struct_size(get, entrytable, get->num_dests);
if (*len != size) {
- pr_err("length: %u != %u\n", *len, size);
+ pr_err("length: %u != %zu\n", *len, size);
ret = -EINVAL;
goto out;
}
--
2.39.5