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Groups > linux.kernel > #1688374
| From | Ben Hutchings <ben@decadent.org.uk> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.16 123/178] l2tp: take reference on sessions being dumped |
| Date | 2017-07-16 16:40 +0200 |
| Message-ID | <u3SSh-fg-67@gated-at.bofh.it> (permalink) |
| References | <u3Sfv-89R-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
3.16.46-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Guillaume Nault <g.nault@alphalink.fr>
commit e08293a4ccbcc993ded0fdc46f1e57926b833d63 upstream.
Take a reference on the sessions returned by l2tp_session_find_nth()
(and rename it l2tp_session_get_nth() to reflect this change), so that
caller is assured that the session isn't going to disappear while
processing it.
For procfs and debugfs handlers, the session is held in the .start()
callback and dropped in .show(). Given that pppol2tp_seq_session_show()
dereferences the associated PPPoL2TP socket and that
l2tp_dfs_seq_session_show() might call pppol2tp_show(), we also need to
call the session's .ref() callback to prevent the socket from going
away from under us.
Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Fixes: 0ad6614048cf ("l2tp: Add debugfs files for dumping l2tp debug info")
Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/l2tp/l2tp_core.c | 8 ++++++--
net/l2tp/l2tp_core.h | 3 ++-
net/l2tp/l2tp_debugfs.c | 10 +++++++---
net/l2tp/l2tp_netlink.c | 7 +++++--
net/l2tp/l2tp_ppp.c | 10 +++++++---
5 files changed, 27 insertions(+), 11 deletions(-)
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -326,7 +326,8 @@ struct l2tp_session *l2tp_session_get(st
}
EXPORT_SYMBOL_GPL(l2tp_session_get);
-struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
+struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
+ bool do_ref)
{
int hash;
struct l2tp_session *session;
@@ -336,6 +337,9 @@ struct l2tp_session *l2tp_session_find_n
for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
if (++count > nth) {
+ l2tp_session_inc_refcount(session);
+ if (do_ref && session->ref)
+ session->ref(session);
read_unlock_bh(&tunnel->hlist_lock);
return session;
}
@@ -346,7 +350,7 @@ struct l2tp_session *l2tp_session_find_n
return NULL;
}
-EXPORT_SYMBOL_GPL(l2tp_session_find_nth);
+EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
/* Lookup a session by interface name.
* This is very inefficient but is only used by management interfaces.
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -246,7 +246,8 @@ struct l2tp_session *l2tp_session_get(st
struct l2tp_session *l2tp_session_find(struct net *net,
struct l2tp_tunnel *tunnel,
u32 session_id);
-struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
+struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
+ bool do_ref);
struct l2tp_session *l2tp_session_get_by_ifname(struct net *net, char *ifname,
bool do_ref);
struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
--- a/net/l2tp/l2tp_debugfs.c
+++ b/net/l2tp/l2tp_debugfs.c
@@ -53,7 +53,7 @@ static void l2tp_dfs_next_tunnel(struct
static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
{
- pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
+ pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx, true);
pd->session_idx++;
if (pd->session == NULL) {
@@ -238,10 +238,14 @@ static int l2tp_dfs_seq_show(struct seq_
}
/* Show the tunnel or session context */
- if (pd->session == NULL)
+ if (!pd->session) {
l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
- else
+ } else {
l2tp_dfs_seq_session_show(m, pd->session);
+ if (pd->session->deref)
+ pd->session->deref(pd->session);
+ l2tp_session_dec_refcount(pd->session);
+ }
out:
return 0;
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -740,7 +740,7 @@ static int l2tp_nl_cmd_session_dump(stru
goto out;
}
- session = l2tp_session_find_nth(tunnel, si);
+ session = l2tp_session_get_nth(tunnel, si, false);
if (session == NULL) {
ti++;
tunnel = NULL;
@@ -750,8 +750,11 @@ static int l2tp_nl_cmd_session_dump(stru
if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI,
- session) <= 0)
+ session) <= 0) {
+ l2tp_session_dec_refcount(session);
break;
+ }
+ l2tp_session_dec_refcount(session);
si++;
}
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1579,7 +1579,7 @@ static void pppol2tp_next_tunnel(struct
static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
{
- pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
+ pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx, true);
pd->session_idx++;
if (pd->session == NULL) {
@@ -1706,10 +1706,14 @@ static int pppol2tp_seq_show(struct seq_
/* Show the tunnel or session context.
*/
- if (pd->session == NULL)
+ if (!pd->session) {
pppol2tp_seq_tunnel_show(m, pd->tunnel);
- else
+ } else {
pppol2tp_seq_session_show(m, pd->session);
+ if (pd->session->deref)
+ pd->session->deref(pd->session);
+ l2tp_session_dec_refcount(pd->session);
+ }
out:
return 0;
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[PATCH 3.16 000/178] 3.16.46-rc1 review Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 077/178] s390/decompressor: fix initrd corruption caused by bss clear Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 132/178] metag/usercopy: Set flags before ADDZ Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
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[PATCH 3.16 144/178] x86/vdso: Ensure vdso32_enabled gets set to valid values only Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 168/178] macvlan: Fix device ref leak when purging bc_queue Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 048/178] futex: Add missing error handling to FUTEX_REQUEUE_PI Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 123/178] l2tp: take reference on sessions being dumped Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 056/178] Input: iforce - validate number of endpoints before using them Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 073/178] net: unix: properly re-increment inflight counter of GC discarded candidates Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
Re: [PATCH 3.16 000/178] 3.16.46-rc1 review Guenter Roeck <linux@roeck-us.net> - 2017-07-16 16:40 +0200
Re: [PATCH 3.16 000/178] 3.16.46-rc1 review Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 18:40 +0200
[PATCH 3.16 007/178] batman-adv: Keep fragments equally sized Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 107/178] drm/vmwgfx: Remove getparam error message Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 072/178] ALSA: seq: Fix racy cell insertions during snd_seq_pool_done() Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 055/178] mmc: ushc: fix NULL-deref at probe Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 136/178] Reset TreeId to zero on SMB2 TREE_CONNECT Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 175/178] char: lp: fix possible integer overflow in lp_setup() Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:40 +0200
[PATCH 3.16 044/178] usb-core: Add LINEAR_FRAME_INTR_BINTERVAL USB quirk Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
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[PATCH 3.16 066/178] usb: hub: Fix crash after failure to read BOS descriptor Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 166/178] net: ipv6: send unsolicited NA if enabled for all interfaces Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 006/178] tracing: Add #undef to fix compile error Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 004/178] kprobes/x86: Fix kernel panic when certain exception-handling addresses are probed Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 170/178] ipv6: move stub initialization after ipv6 setup completion Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 025/178] USB: iowarrior: fix NULL-deref in write Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 150/178] cpupower: Fix turbo frequency reporting for pre-Sandy Bridge cores Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 176/178] fs/exec.c: account for argv/envp pointers Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 127/178] ring-buffer: Fix return value check in test_ringbuffer() Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 015/178] Input: i8042 - add noloop quirk for Dell Embedded Box PC 3000 Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 167/178] Input: i8042 - add Clevo P650RS to the i8042 reset list Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 050/178] iio: adc: ti_am335x_adc: fix fifo overrun recovery Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 049/178] ext4: mark inode dirty after converting inline directory Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
[PATCH 3.16 116/178] include/linux/kernel.h: change abs() macro so it uses consistent return type Ben Hutchings <ben@decadent.org.uk> - 2017-07-16 16:50 +0200
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