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Subject[PATCH 4.9 09/83] ipv4/igmp: fix another memory leak in igmpv3_del_delrec()
Date
From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 3580d04aa674383c42de7b635d28e52a1e5bc72c ]

syzbot reported memory leaks [1] that I have back tracked to
a missing cleanup from igmpv3_del_delrec() when
(im->sfmode != MCAST_INCLUDE)

Add ip_sf_list_clear_all() and kfree_pmc() helpers to explicitely
handle the cleanups before freeing.

[1]

BUG: memory leak
unreferenced object 0xffff888123e32b00 (size 64):
comm "softirq", pid 0, jiffies 4294942968 (age 8.010s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 e0 00 00 01 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000006105011b>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
[<000000006105011b>] slab_post_alloc_hook mm/slab.h:439 [inline]
[<000000006105011b>] slab_alloc mm/slab.c:3326 [inline]
[<000000006105011b>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
[<000000004bba8073>] kmalloc include/linux/slab.h:547 [inline]
[<000000004bba8073>] kzalloc include/linux/slab.h:742 [inline]
[<000000004bba8073>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
[<000000004bba8073>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
[<00000000a46a65a0>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
[<000000005956ca89>] do_ip_setsockopt.isra.0+0x1795/0x1930 net/ipv4/ip_sockglue.c:957
[<00000000848e2d2f>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
[<00000000b9db185c>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
[<000000003028e438>] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3130
[<0000000015b65589>] __sys_setsockopt+0x98/0x120 net/socket.c:2078
[<00000000ac198ef0>] __do_sys_setsockopt net/socket.c:2089 [inline]
[<00000000ac198ef0>] __se_sys_setsockopt net/socket.c:2086 [inline]
[<00000000ac198ef0>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
[<000000000a770437>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
[<00000000d3adb93b>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 9c8bb163ae78 ("igmp, mld: Fix memory leak in igmpv3/mld_del_delrec()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hangbin Liu <liuhangbin@gmail.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/igmp.c | 47 ++++++++++++++++++++++++++++++-----------------
1 file changed, 30 insertions(+), 17 deletions(-)

--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -635,6 +635,24 @@ static void igmpv3_clear_zeros(struct ip
}
}

+static void ip_sf_list_clear_all(struct ip_sf_list *psf)
+{
+ struct ip_sf_list *next;
+
+ while (psf) {
+ next = psf->sf_next;
+ kfree(psf);
+ psf = next;
+ }
+}
+
+static void kfree_pmc(struct ip_mc_list *pmc)
+{
+ ip_sf_list_clear_all(pmc->sources);
+ ip_sf_list_clear_all(pmc->tomb);
+ kfree(pmc);
+}
+
static void igmpv3_send_cr(struct in_device *in_dev)
{
struct ip_mc_list *pmc, *pmc_prev, *pmc_next;
@@ -671,7 +689,7 @@ static void igmpv3_send_cr(struct in_dev
else
in_dev->mc_tomb = pmc_next;
in_dev_put(pmc->interface);
- kfree(pmc);
+ kfree_pmc(pmc);
} else
pmc_prev = pmc;
}
@@ -1195,12 +1213,16 @@ static void igmpv3_del_delrec(struct in_
im->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
if (im->sfmode == MCAST_INCLUDE) {
im->tomb = pmc->tomb;
+ pmc->tomb = NULL;
+
im->sources = pmc->sources;
+ pmc->sources = NULL;
+
for (psf = im->sources; psf; psf = psf->sf_next)
psf->sf_crcount = im->crcount;
}
in_dev_put(pmc->interface);
- kfree(pmc);
+ kfree_pmc(pmc);
}
spin_unlock_bh(&im->lock);
}
@@ -1221,21 +1243,18 @@ static void igmpv3_clear_delrec(struct i
nextpmc = pmc->next;
ip_mc_clear_src(pmc);
in_dev_put(pmc->interface);
- kfree(pmc);
+ kfree_pmc(pmc);
}
/* clear dead sources, too */
rcu_read_lock();
for_each_pmc_rcu(in_dev, pmc) {
- struct ip_sf_list *psf, *psf_next;
+ struct ip_sf_list *psf;

spin_lock_bh(&pmc->lock);
psf = pmc->tomb;
pmc->tomb = NULL;
spin_unlock_bh(&pmc->lock);
- for (; psf; psf = psf_next) {
- psf_next = psf->sf_next;
- kfree(psf);
- }
+ ip_sf_list_clear_all(psf);
}
rcu_read_unlock();
}
@@ -2099,7 +2118,7 @@ static int ip_mc_add_src(struct in_devic

static void ip_mc_clear_src(struct ip_mc_list *pmc)
{
- struct ip_sf_list *psf, *nextpsf, *tomb, *sources;
+ struct ip_sf_list *tomb, *sources;

spin_lock_bh(&pmc->lock);
tomb = pmc->tomb;
@@ -2111,14 +2130,8 @@ static void ip_mc_clear_src(struct ip_mc
pmc->sfcount[MCAST_EXCLUDE] = 1;
spin_unlock_bh(&pmc->lock);

- for (psf = tomb; psf; psf = nextpsf) {
- nextpsf = psf->sf_next;
- kfree(psf);
- }
- for (psf = sources; psf; psf = nextpsf) {
- nextpsf = psf->sf_next;
- kfree(psf);
- }
+ ip_sf_list_clear_all(tomb);
+ ip_sf_list_clear_all(sources);
}

/* Join a multicast group

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