[PATCH 4.20 39/76] net: nfc: Fix NULL dereference on nfc_llcp_build_tlv fails

4.20-stable review patch. If anyone has any objections, please let me know.

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From: YueHaibing yuehaibing@huawei.com

[ Upstream commit 58bdd544e2933a21a51eecf17c3f5f94038261b5 ]

KASAN report this:

BUG: KASAN: null-ptr-deref in nfc_llcp_build_gb+0x37f/0x540 [nfc] Read of size 3 at addr 0000000000000000 by task syz-executor.0/5401

CPU: 0 PID: 5401 Comm: syz-executor.0 Not tainted 5.0.0-rc7+ #45 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xfa/0x1ce lib/dump_stack.c:113 kasan_report+0x171/0x18d mm/kasan/report.c:321 memcpy+0x1f/0x50 mm/kasan/common.c:130 nfc_llcp_build_gb+0x37f/0x540 [nfc] nfc_llcp_register_device+0x6eb/0xb50 [nfc] nfc_register_device+0x50/0x1d0 [nfc] nfcsim_device_new+0x394/0x67d [nfcsim] ? 0xffffffffc1080000 nfcsim_init+0x6b/0x1000 [nfcsim] do_one_initcall+0xfa/0x5ca init/main.c:887 do_init_module+0x204/0x5f6 kernel/module.c:3460 load_module+0x66b2/0x8570 kernel/module.c:3808 __do_sys_finit_module+0x238/0x2a0 kernel/module.c:3902 do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x462e99 Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9cb79dcc58 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 000000000073bf00 RCX: 0000000000462e99 RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003 RBP: 00007f9cb79dcc70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9cb79dd6bc R13: 00000000004bcefb R14: 00000000006f7030 R15: 0000000000000004

nfc_llcp_build_tlv will return NULL on fails, caller should check it, otherwise will trigger a NULL dereference.

Reported-by: Hulk Robot hulkci@huawei.com Fixes: eda21f16a5ed ("NFC: Set MIU and RW values from CONNECT and CC LLCP frames") Fixes: d646960f7986 ("NFC: Initial LLCP support") Signed-off-by: YueHaibing yuehaibing@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/nfc/llcp_commands.c | 20 ++++++++++++++++++++ net/nfc/llcp_core.c | 24 ++++++++++++++++++++---- 2 files changed, 40 insertions(+), 4 deletions(-)

--- a/net/nfc/llcp_commands.c +++ b/net/nfc/llcp_commands.c @@ -419,6 +419,10 @@ int nfc_llcp_send_connect(struct nfc_llc sock->service_name, sock->service_name_len, &service_name_tlv_length); + if (!service_name_tlv) { + err = -ENOMEM; + goto error_tlv; + } size += service_name_tlv_length; }

@@ -429,9 +433,17 @@ int nfc_llcp_send_connect(struct nfc_llc

miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0, &miux_tlv_length); + if (!miux_tlv) { + err = -ENOMEM; + goto error_tlv; + } size += miux_tlv_length;

rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length); + if (!rw_tlv) { + err = -ENOMEM; + goto error_tlv; + } size += rw_tlv_length;

pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len); @@ -484,9 +496,17 @@ int nfc_llcp_send_cc(struct nfc_llcp_soc

miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0, &miux_tlv_length); + if (!miux_tlv) { + err = -ENOMEM; + goto error_tlv; + } size += miux_tlv_length;

rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length); + if (!rw_tlv) { + err = -ENOMEM; + goto error_tlv; + } size += rw_tlv_length;

skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size); --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -532,10 +532,10 @@ static u8 nfc_llcp_reserve_sdp_ssap(stru

static int nfc_llcp_build_gb(struct nfc_llcp_local *local) { - u8 *gb_cur, *version_tlv, version, version_length; - u8 *lto_tlv, lto_length; - u8 *wks_tlv, wks_length; - u8 *miux_tlv, miux_length; + u8 *gb_cur, version, version_length; + u8 lto_length, wks_length, miux_length; + u8 *version_tlv = NULL, *lto_tlv = NULL, + *wks_tlv = NULL, *miux_tlv = NULL; __be16 wks = cpu_to_be16(local->local_wks); u8 gb_len = 0; int ret = 0; @@ -543,17 +543,33 @@ static int nfc_llcp_build_gb(struct nfc_ version = LLCP_VERSION_11; version_tlv = nfc_llcp_build_tlv(LLCP_TLV_VERSION, &version, 1, &version_length); + if (!version_tlv) { + ret = -ENOMEM; + goto out; + } gb_len += version_length;

lto_tlv = nfc_llcp_build_tlv(LLCP_TLV_LTO, &local->lto, 1, &lto_length); + if (!lto_tlv) { + ret = -ENOMEM; + goto out; + } gb_len += lto_length;

pr_debug("Local wks 0x%lx\n", local->local_wks); wks_tlv = nfc_llcp_build_tlv(LLCP_TLV_WKS, (u8 *)&wks, 2, &wks_length); + if (!wks_tlv) { + ret = -ENOMEM; + goto out; + } gb_len += wks_length;

miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&local->miux, 0, &miux_length); + if (!miux_tlv) { + ret = -ENOMEM; + goto out; + } gb_len += miux_length;

gb_len += ARRAY_SIZE(llcp_magic);