diff mbox series

[net-next,v3,3/9] Bluetooth: RFCOMM: avoid leaving dangling sk pointer in rfcomm_sock_alloc()

Message ID 20241014153808.51894-4-ignat@cloudflare.com (mailing list archive)
State Accepted
Commit 3945c799f12b8d1f49a3b48369ca494d981ac465
Delegated to: Netdev Maintainers
Headers show
Series do not leave dangling sk pointers in pf->create functions | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 18 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-10-15--06-00 (tests: 777)

Commit Message

Ignat Korchagin Oct. 14, 2024, 3:38 p.m. UTC 
bt_sock_alloc() attaches allocated sk object to the provided sock object.
If rfcomm_dlc_alloc() fails, we release the sk object, but leave the
dangling pointer in the sock object, which may cause use-after-free.

Fix this by swapping calls to bt_sock_alloc() and rfcomm_dlc_alloc().

Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
---
 net/bluetooth/rfcomm/sock.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Comments

Kuniyuki Iwashima Oct. 14, 2024, 9:29 p.m. UTC | #1 
From: Ignat Korchagin <ignat@cloudflare.com>
Date: Mon, 14 Oct 2024 16:38:02 +0100
> bt_sock_alloc() attaches allocated sk object to the provided sock object.
> If rfcomm_dlc_alloc() fails, we release the sk object, but leave the
> dangling pointer in the sock object, which may cause use-after-free.
> 
> Fix this by swapping calls to bt_sock_alloc() and rfcomm_dlc_alloc().
> 
> Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Eric Dumazet Oct. 15, 2024, 8:04 a.m. UTC | #2 
On Mon, Oct 14, 2024 at 11:30 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote:
>
> From: Ignat Korchagin <ignat@cloudflare.com>
> Date: Mon, 14 Oct 2024 16:38:02 +0100
> > bt_sock_alloc() attaches allocated sk object to the provided sock object.
> > If rfcomm_dlc_alloc() fails, we release the sk object, but leave the
> > dangling pointer in the sock object, which may cause use-after-free.
> >
> > Fix this by swapping calls to bt_sock_alloc() and rfcomm_dlc_alloc().
> >
> > Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
>
> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>

Reviewed-by: Eric Dumazet <edumazet@google.com>
diff mbox series

Patch

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index f48250e3f2e1..355e1a1698f5 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -274,13 +274,13 @@  static struct sock *rfcomm_sock_alloc(struct net *net, struct socket *sock,
 	struct rfcomm_dlc *d;
 	struct sock *sk;
 
-	sk = bt_sock_alloc(net, sock, &rfcomm_proto, proto, prio, kern);
-	if (!sk)
+	d = rfcomm_dlc_alloc(prio);
+	if (!d)
 		return NULL;
 
-	d = rfcomm_dlc_alloc(prio);
-	if (!d) {
-		sk_free(sk);
+	sk = bt_sock_alloc(net, sock, &rfcomm_proto, proto, prio, kern);
+	if (!sk) {
+		rfcomm_dlc_free(d);
 		return NULL;
 	}