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authorVasiliy Kulikov <segoon@openwall.com>2011-03-20 15:42:52 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-14 13:02:32 -0700
commit5e8ba35db5884f7e3449eba28886a8f10c7e911e (patch)
treebe9dc79e0bd7c170a572eb7175b3ee9dde29f16e
parenta988a0f40682cd871e3f5ad61fc779e5c7d36f5e (diff)
netfilter: ipt_CLUSTERIP: fix buffer overflow
commit 961ed183a9fd080cf306c659b8736007e44065a5 upstream. 'buffer' string is copied from userspace. It is not checked whether it is zero terminated. This may lead to overflow inside of simple_strtoul(). Changli Gao suggested to copy not more than user supplied 'size' bytes. It was introduced before the git epoch. Files "ipt_CLUSTERIP/*" are root writable only by default, however, on some setups permissions might be relaxed to e.g. network admin user. Signed-off-by: Vasiliy Kulikov <segoon@openwall.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/ipv4/netfilter/ipt_CLUSTERIP.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 1e26a489765..af7dec683e1 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -669,8 +669,11 @@ static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
char buffer[PROC_WRITELEN+1];
unsigned long nodenum;
- if (copy_from_user(buffer, input, PROC_WRITELEN))
+ if (size > PROC_WRITELEN)
+ return -EIO;
+ if (copy_from_user(buffer, input, size))
return -EFAULT;
+ buffer[size] = 0;
if (*buffer == '+') {
nodenum = simple_strtoul(buffer+1, NULL, 10);