path: root/src
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authorPhil Sutter <>2016-08-12 01:33:37 +0200
committerPablo Neira Ayuso <>2016-08-12 01:45:40 +0200
commitd26feca2c9c19b650b5a7554b5a412ceca990b7a (patch)
tree8656f3cad4c3b83c2751e6bdaba8f91239b7a48b /src
parente381cd99e9eb0e9519a976c8288f6b9e051ada3a (diff)
common: Avoid integer overflow in nftnl_batch_is_supported()
time() may return -1 which is then assigned to an unsigned integer type and used as sequence number. The following code increments that number multiple times, so it may overflow and get libmnl confused. To avoid this, fall back to a starting sequence number of zero in case the call to time() failed. Signed-off-by: Phil Sutter <> Signed-off-by: Pablo Neira Ayuso <>
Diffstat (limited to 'src')
1 files changed, 3 insertions, 0 deletions
diff --git a/src/common.c b/src/common.c
index bf4176c..2189cc8 100644
--- a/src/common.c
+++ b/src/common.c
@@ -192,6 +192,9 @@ int nftnl_batch_is_supported(void)
uint32_t seq = time(NULL), req_seq;
int ret;
+ if (seq == (uint32_t)-1)
+ seq = 0;
nl = mnl_socket_open(NETLINK_NETFILTER);
if (nl == NULL)
return -1;