| Message ID | 20231110163947.1605168-1-syoshida@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | fb317eb23b5ee4c37b0656a9a52a3db58d9dd072 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] tipc: Fix kernel-infoleak due to uninitialized TLV value | expand |
On Sat, Nov 11, 2023 at 01:39:47AM +0900, Shigeru Yoshida wrote: > KMSAN reported the following kernel-infoleak issue: > > ===================================================== > BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] > BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] > BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] > BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] > BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] > BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 > instrument_copy_to_user include/linux/instrumented.h:114 [inline] > copy_to_user_iter lib/iov_iter.c:24 [inline] > iterate_ubuf include/linux/iov_iter.h:29 [inline] > iterate_and_advance2 include/linux/iov_iter.h:245 [inline] > iterate_and_advance include/linux/iov_iter.h:271 [inline] > _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 > copy_to_iter include/linux/uio.h:197 [inline] > simple_copy_to_iter net/core/datagram.c:532 [inline] > __skb_datagram_iter.5+0x148/0xe30 net/core/datagram.c:420 > skb_copy_datagram_iter+0x52/0x210 net/core/datagram.c:546 > skb_copy_datagram_msg include/linux/skbuff.h:3960 [inline] > netlink_recvmsg+0x43d/0x1630 net/netlink/af_netlink.c:1967 > sock_recvmsg_nosec net/socket.c:1044 [inline] > sock_recvmsg net/socket.c:1066 [inline] > __sys_recvfrom+0x476/0x860 net/socket.c:2246 > __do_sys_recvfrom net/socket.c:2264 [inline] > __se_sys_recvfrom net/socket.c:2260 [inline] > __x64_sys_recvfrom+0x130/0x200 net/socket.c:2260 > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > Uninit was created at: > slab_post_alloc_hook+0x103/0x9e0 mm/slab.h:768 > slab_alloc_node mm/slub.c:3478 [inline] > kmem_cache_alloc_node+0x5f7/0xb50 mm/slub.c:3523 > kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:560 > __alloc_skb+0x2fd/0x770 net/core/skbuff.c:651 > alloc_skb include/linux/skbuff.h:1286 [inline] > tipc_tlv_alloc net/tipc/netlink_compat.c:156 [inline] > tipc_get_err_tlv+0x90/0x5d0 net/tipc/netlink_compat.c:170 > tipc_nl_compat_recv+0x1042/0x15d0 net/tipc/netlink_compat.c:1324 > genl_family_rcv_msg_doit net/netlink/genetlink.c:972 [inline] > genl_family_rcv_msg net/netlink/genetlink.c:1052 [inline] > genl_rcv_msg+0x1220/0x12c0 net/netlink/genetlink.c:1067 > netlink_rcv_skb+0x4a4/0x6a0 net/netlink/af_netlink.c:2545 > genl_rcv+0x41/0x60 net/netlink/genetlink.c:1076 > netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] > netlink_unicast+0xf4b/0x1230 net/netlink/af_netlink.c:1368 > netlink_sendmsg+0x1242/0x1420 net/netlink/af_netlink.c:1910 > sock_sendmsg_nosec net/socket.c:730 [inline] > __sock_sendmsg net/socket.c:745 [inline] > ____sys_sendmsg+0x997/0xd60 net/socket.c:2588 > ___sys_sendmsg+0x271/0x3b0 net/socket.c:2642 > __sys_sendmsg net/socket.c:2671 [inline] > __do_sys_sendmsg net/socket.c:2680 [inline] > __se_sys_sendmsg net/socket.c:2678 [inline] > __x64_sys_sendmsg+0x2fa/0x4a0 net/socket.c:2678 > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > Bytes 34-35 of 36 are uninitialized > Memory access of size 36 starts at ffff88802d464a00 > Data copied to user address 00007ff55033c0a0 > > CPU: 0 PID: 30322 Comm: syz-executor.0 Not tainted 6.6.0-14500-g1c41041124bd #10 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 > ===================================================== > > tipc_add_tlv() puts TLV descriptor and value onto `skb`. This size is > calculated with TLV_SPACE() macro. It adds the size of struct tlv_desc and > the length of TLV value passed as an argument, and aligns the result to a > multiple of TLV_ALIGNTO, i.e., a multiple of 4 bytes. > > If the size of struct tlv_desc plus the length of TLV value is not aligned, > the current implementation leaves the remaining bytes uninitialized. This > is the cause of the above kernel-infoleak issue. > > This patch resolves this issue by clearing data up to an aligned size. > > Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat") > Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> Thanks Yoshida-san, I agree with both your analysis and that the fix is correct. I also agree that the problem was introduced by the cited commit. I did wonder if there would be an advantage to only zeroing the otherwise uninitialised portion of tlv, but I guess that the complexity isn't worth any gain: all of TLV likely fits into a single cacheline anyway. Reviewed-by: Simon Horman <horms@kernel.org> > --- > net/tipc/netlink_compat.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c > index 5bc076f2fa74..c763008a8adb 100644 > --- a/net/tipc/netlink_compat.c > +++ b/net/tipc/netlink_compat.c > @@ -102,6 +102,7 @@ static int tipc_add_tlv(struct sk_buff *skb, u16 type, void *data, u16 len) > return -EMSGSIZE; > > skb_put(skb, TLV_SPACE(len)); > + memset(tlv, 0, TLV_SPACE(len)); > tlv->tlv_type = htons(type); > tlv->tlv_len = htons(TLV_LENGTH(len)); > if (len && data) > -- > 2.41.0 > >
On Sun, 12 Nov 2023 10:25:13 +0000, Simon Horman wrote: > On Sat, Nov 11, 2023 at 01:39:47AM +0900, Shigeru Yoshida wrote: >> KMSAN reported the following kernel-infoleak issue: >> >> ===================================================== >> BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] >> BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] >> BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] >> BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] >> BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] >> BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 >> instrument_copy_to_user include/linux/instrumented.h:114 [inline] >> copy_to_user_iter lib/iov_iter.c:24 [inline] >> iterate_ubuf include/linux/iov_iter.h:29 [inline] >> iterate_and_advance2 include/linux/iov_iter.h:245 [inline] >> iterate_and_advance include/linux/iov_iter.h:271 [inline] >> _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 >> copy_to_iter include/linux/uio.h:197 [inline] >> simple_copy_to_iter net/core/datagram.c:532 [inline] >> __skb_datagram_iter.5+0x148/0xe30 net/core/datagram.c:420 >> skb_copy_datagram_iter+0x52/0x210 net/core/datagram.c:546 >> skb_copy_datagram_msg include/linux/skbuff.h:3960 [inline] >> netlink_recvmsg+0x43d/0x1630 net/netlink/af_netlink.c:1967 >> sock_recvmsg_nosec net/socket.c:1044 [inline] >> sock_recvmsg net/socket.c:1066 [inline] >> __sys_recvfrom+0x476/0x860 net/socket.c:2246 >> __do_sys_recvfrom net/socket.c:2264 [inline] >> __se_sys_recvfrom net/socket.c:2260 [inline] >> __x64_sys_recvfrom+0x130/0x200 net/socket.c:2260 >> do_syscall_x64 arch/x86/entry/common.c:51 [inline] >> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 >> entry_SYSCALL_64_after_hwframe+0x63/0x6b >> >> Uninit was created at: >> slab_post_alloc_hook+0x103/0x9e0 mm/slab.h:768 >> slab_alloc_node mm/slub.c:3478 [inline] >> kmem_cache_alloc_node+0x5f7/0xb50 mm/slub.c:3523 >> kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:560 >> __alloc_skb+0x2fd/0x770 net/core/skbuff.c:651 >> alloc_skb include/linux/skbuff.h:1286 [inline] >> tipc_tlv_alloc net/tipc/netlink_compat.c:156 [inline] >> tipc_get_err_tlv+0x90/0x5d0 net/tipc/netlink_compat.c:170 >> tipc_nl_compat_recv+0x1042/0x15d0 net/tipc/netlink_compat.c:1324 >> genl_family_rcv_msg_doit net/netlink/genetlink.c:972 [inline] >> genl_family_rcv_msg net/netlink/genetlink.c:1052 [inline] >> genl_rcv_msg+0x1220/0x12c0 net/netlink/genetlink.c:1067 >> netlink_rcv_skb+0x4a4/0x6a0 net/netlink/af_netlink.c:2545 >> genl_rcv+0x41/0x60 net/netlink/genetlink.c:1076 >> netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] >> netlink_unicast+0xf4b/0x1230 net/netlink/af_netlink.c:1368 >> netlink_sendmsg+0x1242/0x1420 net/netlink/af_netlink.c:1910 >> sock_sendmsg_nosec net/socket.c:730 [inline] >> __sock_sendmsg net/socket.c:745 [inline] >> ____sys_sendmsg+0x997/0xd60 net/socket.c:2588 >> ___sys_sendmsg+0x271/0x3b0 net/socket.c:2642 >> __sys_sendmsg net/socket.c:2671 [inline] >> __do_sys_sendmsg net/socket.c:2680 [inline] >> __se_sys_sendmsg net/socket.c:2678 [inline] >> __x64_sys_sendmsg+0x2fa/0x4a0 net/socket.c:2678 >> do_syscall_x64 arch/x86/entry/common.c:51 [inline] >> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 >> entry_SYSCALL_64_after_hwframe+0x63/0x6b >> >> Bytes 34-35 of 36 are uninitialized >> Memory access of size 36 starts at ffff88802d464a00 >> Data copied to user address 00007ff55033c0a0 >> >> CPU: 0 PID: 30322 Comm: syz-executor.0 Not tainted 6.6.0-14500-g1c41041124bd #10 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 >> ===================================================== >> >> tipc_add_tlv() puts TLV descriptor and value onto `skb`. This size is >> calculated with TLV_SPACE() macro. It adds the size of struct tlv_desc and >> the length of TLV value passed as an argument, and aligns the result to a >> multiple of TLV_ALIGNTO, i.e., a multiple of 4 bytes. >> >> If the size of struct tlv_desc plus the length of TLV value is not aligned, >> the current implementation leaves the remaining bytes uninitialized. This >> is the cause of the above kernel-infoleak issue. >> >> This patch resolves this issue by clearing data up to an aligned size. >> >> Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat") >> Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> > > Thanks Yoshida-san, > > I agree with both your analysis and that the fix is correct. > I also agree that the problem was introduced by the cited commit. > > I did wonder if there would be an advantage to only zeroing the > otherwise uninitialised portion of tlv, but I guess that the complexity > isn't worth any gain: all of TLV likely fits into a single cacheline > anyway. > > Reviewed-by: Simon Horman <horms@kernel.org> Hi Simon, Thank you so much for always reviewing my work :) Shigeru > >> --- >> net/tipc/netlink_compat.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c >> index 5bc076f2fa74..c763008a8adb 100644 >> --- a/net/tipc/netlink_compat.c >> +++ b/net/tipc/netlink_compat.c >> @@ -102,6 +102,7 @@ static int tipc_add_tlv(struct sk_buff *skb, u16 type, void *data, u16 len) >> return -EMSGSIZE; >> >> skb_put(skb, TLV_SPACE(len)); >> + memset(tlv, 0, TLV_SPACE(len)); >> tlv->tlv_type = htons(type); >> tlv->tlv_len = htons(TLV_LENGTH(len)); >> if (len && data) >> -- >> 2.41.0 >> >> >
Hello: This patch was applied to netdev/net.git (main) by David S. Miller <davem@davemloft.net>: On Sat, 11 Nov 2023 01:39:47 +0900 you wrote: > KMSAN reported the following kernel-infoleak issue: > > ===================================================== > BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] > BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] > BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] > BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] > BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] > BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 > instrument_copy_to_user include/linux/instrumented.h:114 [inline] > copy_to_user_iter lib/iov_iter.c:24 [inline] > iterate_ubuf include/linux/iov_iter.h:29 [inline] > iterate_and_advance2 include/linux/iov_iter.h:245 [inline] > iterate_and_advance include/linux/iov_iter.h:271 [inline] > _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 > copy_to_iter include/linux/uio.h:197 [inline] > simple_copy_to_iter net/core/datagram.c:532 [inline] > __skb_datagram_iter.5+0x148/0xe30 net/core/datagram.c:420 > skb_copy_datagram_iter+0x52/0x210 net/core/datagram.c:546 > skb_copy_datagram_msg include/linux/skbuff.h:3960 [inline] > netlink_recvmsg+0x43d/0x1630 net/netlink/af_netlink.c:1967 > sock_recvmsg_nosec net/socket.c:1044 [inline] > sock_recvmsg net/socket.c:1066 [inline] > __sys_recvfrom+0x476/0x860 net/socket.c:2246 > __do_sys_recvfrom net/socket.c:2264 [inline] > __se_sys_recvfrom net/socket.c:2260 [inline] > __x64_sys_recvfrom+0x130/0x200 net/socket.c:2260 > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > [...] Here is the summary with links: - [net] tipc: Fix kernel-infoleak due to uninitialized TLV value https://git.kernel.org/netdev/net/c/fb317eb23b5e You are awesome, thank you!
diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c index 5bc076f2fa74..c763008a8adb 100644 --- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -102,6 +102,7 @@ static int tipc_add_tlv(struct sk_buff *skb, u16 type, void *data, u16 len) return -EMSGSIZE; skb_put(skb, TLV_SPACE(len)); + memset(tlv, 0, TLV_SPACE(len)); tlv->tlv_type = htons(type); tlv->tlv_len = htons(TLV_LENGTH(len)); if (len && data)
KMSAN reported the following kernel-infoleak issue: ===================================================== BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 instrument_copy_to_user include/linux/instrumented.h:114 [inline] copy_to_user_iter lib/iov_iter.c:24 [inline] iterate_ubuf include/linux/iov_iter.h:29 [inline] iterate_and_advance2 include/linux/iov_iter.h:245 [inline] iterate_and_advance include/linux/iov_iter.h:271 [inline] _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 copy_to_iter include/linux/uio.h:197 [inline] simple_copy_to_iter net/core/datagram.c:532 [inline] __skb_datagram_iter.5+0x148/0xe30 net/core/datagram.c:420 skb_copy_datagram_iter+0x52/0x210 net/core/datagram.c:546 skb_copy_datagram_msg include/linux/skbuff.h:3960 [inline] netlink_recvmsg+0x43d/0x1630 net/netlink/af_netlink.c:1967 sock_recvmsg_nosec net/socket.c:1044 [inline] sock_recvmsg net/socket.c:1066 [inline] __sys_recvfrom+0x476/0x860 net/socket.c:2246 __do_sys_recvfrom net/socket.c:2264 [inline] __se_sys_recvfrom net/socket.c:2260 [inline] __x64_sys_recvfrom+0x130/0x200 net/socket.c:2260 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit was created at: slab_post_alloc_hook+0x103/0x9e0 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x5f7/0xb50 mm/slub.c:3523 kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:560 __alloc_skb+0x2fd/0x770 net/core/skbuff.c:651 alloc_skb include/linux/skbuff.h:1286 [inline] tipc_tlv_alloc net/tipc/netlink_compat.c:156 [inline] tipc_get_err_tlv+0x90/0x5d0 net/tipc/netlink_compat.c:170 tipc_nl_compat_recv+0x1042/0x15d0 net/tipc/netlink_compat.c:1324 genl_family_rcv_msg_doit net/netlink/genetlink.c:972 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1052 [inline] genl_rcv_msg+0x1220/0x12c0 net/netlink/genetlink.c:1067 netlink_rcv_skb+0x4a4/0x6a0 net/netlink/af_netlink.c:2545 genl_rcv+0x41/0x60 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0xf4b/0x1230 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x1242/0x1420 net/netlink/af_netlink.c:1910 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x997/0xd60 net/socket.c:2588 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2642 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2680 [inline] __se_sys_sendmsg net/socket.c:2678 [inline] __x64_sys_sendmsg+0x2fa/0x4a0 net/socket.c:2678 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Bytes 34-35 of 36 are uninitialized Memory access of size 36 starts at ffff88802d464a00 Data copied to user address 00007ff55033c0a0 CPU: 0 PID: 30322 Comm: syz-executor.0 Not tainted 6.6.0-14500-g1c41041124bd #10 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 ===================================================== tipc_add_tlv() puts TLV descriptor and value onto `skb`. This size is calculated with TLV_SPACE() macro. It adds the size of struct tlv_desc and the length of TLV value passed as an argument, and aligns the result to a multiple of TLV_ALIGNTO, i.e., a multiple of 4 bytes. If the size of struct tlv_desc plus the length of TLV value is not aligned, the current implementation leaves the remaining bytes uninitialized. This is the cause of the above kernel-infoleak issue. This patch resolves this issue by clearing data up to an aligned size. Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat") Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> --- net/tipc/netlink_compat.c | 1 + 1 file changed, 1 insertion(+)