From: Sabrina Dubroca <[email protected]>
Date: Mon, 4 Jun 2018 13:55:54 +0200
> commit 0bbbf0e7d0e7 ("ipmr, ip6mr: Unite creation of new mr_table")
> refactored ipmr_new_table, so that it now returns NULL when
> mr_table_alloc fails. Unfortunately, all callers of ipmr_new_table
> expect an ERR_PTR. commit 66fb33254f45 ("ipmr: properly check
> rhltable_init() return value") followed suit.
>
> This can result in NULL deref, when ipmr_rules_exit calls
> ipmr_free_table with NULL net->ipv4.mrt in the
> !CONFIG_IP_MROUTE_MULTIPLE_TABLES version.
>
> This patch makes mr_table_alloc return errors, and changes
> ip6mr_new_table and its callers to return/expect error pointers as
> well. It also removes the version of mr_table_alloc defined under
> !CONFIG_IP_MROUTE_COMMON, since it is never used.
>
> Fixes: 0bbbf0e7d0e7 ("ipmr, ip6mr: Unite creation of new mr_table")
> Fixes: 66fb33254f45 ("ipmr: properly check rhltable_init() return value")
> Signed-off-by: Sabrina Dubroca <[email protected]>
This adds a new warning with gcc-8.1.1 on Fedora 28
CC [M] net/ipv6/ip6mr.o
In file included from ./arch/x86/include/asm/current.h:5,
from ./include/linux/sched.h:12,
from ./include/linux/uaccess.h:5,
from net/ipv6/ip6mr.c:19:
net/ipv6/ip6mr.c: In function ‘ip6_mroute_setsockopt’:
./include/linux/compiler.h:177:26: warning: ‘mrt’ may be used uninitialized in
this function [-Wmaybe-uninitialized]
case 8: *(__u64 *)res = *(volatile __u64 *)p; break; \
^
net/ipv6/ip6mr.c:1752:20: note: ‘mrt’ was declared here
struct mr_table *mrt;
^~~
