diff options
| author | Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> | 2021-05-31 10:21:38 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-06-01 08:43:27 +0300 |
| commit | 4ac06a1e013cf5fdd963317ffd3b968560f33bba (patch) | |
| tree | 6638f0737d4f08a02e7ced318ca8c8706352cb56 | |
| parent | 593f555fbc6091bbaec8dd2a38b47ee643412e61 (diff) | |
| download | linux-4ac06a1e013cf5fdd963317ffd3b968560f33bba.tar.xz | |
nfc: fix NULL ptr dereference in llcp_sock_getname() after failed connect
It's possible to trigger NULL pointer dereference by local unprivileged
user, when calling getsockname() after failed bind() (e.g. the bind
fails because LLCP_SAP_MAX used as SAP):
BUG: kernel NULL pointer dereference, address: 0000000000000000
CPU: 1 PID: 426 Comm: llcp_sock_getna Not tainted 5.13.0-rc2-next-20210521+ #9
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1 04/01/2014
Call Trace:
llcp_sock_getname+0xb1/0xe0
__sys_getpeername+0x95/0xc0
? lockdep_hardirqs_on_prepare+0xd5/0x180
? syscall_enter_from_user_mode+0x1c/0x40
__x64_sys_getpeername+0x11/0x20
do_syscall_64+0x36/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xae
This can be reproduced with Syzkaller C repro (bind followed by
getpeername):
https://syzkaller.appspot.com/x/repro.c?x=14def446e00000
Cc: <stable@vger.kernel.org>
Fixes: d646960f7986 ("NFC: Initial LLCP support")
Reported-by: syzbot+80fb126e7f7d8b1a5914@syzkaller.appspotmail.com
Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210531072138.5219-1-krzysztof.kozlowski@canonical.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/nfc/llcp_sock.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c index 53dbe733f998..6cfd30fc0798 100644 --- a/net/nfc/llcp_sock.c +++ b/net/nfc/llcp_sock.c @@ -110,6 +110,7 @@ static int llcp_sock_bind(struct socket *sock, struct sockaddr *addr, int alen) if (!llcp_sock->service_name) { nfc_llcp_local_put(llcp_sock->local); llcp_sock->local = NULL; + llcp_sock->dev = NULL; ret = -ENOMEM; goto put_dev; } @@ -119,6 +120,7 @@ static int llcp_sock_bind(struct socket *sock, struct sockaddr *addr, int alen) llcp_sock->local = NULL; kfree(llcp_sock->service_name); llcp_sock->service_name = NULL; + llcp_sock->dev = NULL; ret = -EADDRINUSE; goto put_dev; } |