Re: [PATCH] net: ipmr: limit MRT_TABLE identifiers
From: Chen Gang <hidden>
Date: 2012-11-26 01:22:01
于 2012年11月26日 03:44, Eric Dumazet 写道:
From: Eric Dumazet <edumazet@google.com> Name of pimreg devices are built from following format : char name[IFNAMSIZ]; // IFNAMSIZ == 16 sprintf(name, "pimreg%u", mrt->id); We must therefore limit mrt->id to 9 decimal digits or risk a buffer overflow and a crash. Restrict table identifiers in [0 ... 999999999] interval.
if we have to stick to "pimreg%u" (or will hurt the functional features)
suggest to let user mode know this limitation.
define a macro in public header (user mode can know it) and give comments.
use macro instead of number.
remove the comments which is inside internal function.
thanks.
gchen.
quoted hunk ↗ jump to hunk
Reported-by: Chen Gang <redacted> Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/ipv4/ipmr.c | 4 ++++ 1 file changed, 4 insertions(+)diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index 6168c4d..3eab2b2 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c@@ -1318,6 +1318,10 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi if (get_user(v, (u32 __user *)optval)) return -EFAULT; + /* "pimreg%u" should not exceed 16 bytes (IFNAMSIZ) */ + if (v != RT_TABLE_DEFAULT && v >= 1000000000) + return -EINVAL; + rtnl_lock(); ret = 0; if (sk == rtnl_dereference(mrt->mroute_sk)) {
-- Chen Gang Asianux Corporation