https://github.com/torvalds/linux
Revision 3aff8aaca4e36dc8b17eaa011684881a80238966 authored by Maxim Mikityanskiy on 04 October 2022, 21:27:18 UTC, committed by Luiz Augusto von Dentz on 02 November 2022, 21:12:34 UTC
Fix the race condition between the following two flows that run in parallel: 1. l2cap_reassemble_sdu -> chan->ops->recv (l2cap_sock_recv_cb) -> __sock_queue_rcv_skb. 2. bt_sock_recvmsg -> skb_recv_datagram, skb_free_datagram. An SKB can be queued by the first flow and immediately dequeued and freed by the second flow, therefore the callers of l2cap_reassemble_sdu can't use the SKB after that function returns. However, some places continue accessing struct l2cap_ctrl that resides in the SKB's CB for a short time after l2cap_reassemble_sdu returns, leading to a use-after-free condition (the stack trace is below, line numbers for kernel 5.19.8). Fix it by keeping a local copy of struct l2cap_ctrl. BUG: KASAN: use-after-free in l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth Read of size 1 at addr ffff88812025f2f0 by task kworker/u17:3/43169 Workqueue: hci0 hci_rx_work [bluetooth] Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) print_report.cold (mm/kasan/report.c:314 mm/kasan/report.c:429) ? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:493) ? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth l2cap_rx (net/bluetooth/l2cap_core.c:7236 net/bluetooth/l2cap_core.c:7271) bluetooth ret_from_fork (arch/x86/entry/entry_64.S:306) </TASK> Allocated by task 43169: kasan_save_stack (mm/kasan/common.c:39) __kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469) kmem_cache_alloc_node (mm/slab.h:750 mm/slub.c:3243 mm/slub.c:3293) __alloc_skb (net/core/skbuff.c:414) l2cap_recv_frag (./include/net/bluetooth/bluetooth.h:425 net/bluetooth/l2cap_core.c:8329) bluetooth l2cap_recv_acldata (net/bluetooth/l2cap_core.c:8442) bluetooth hci_rx_work (net/bluetooth/hci_core.c:3642 net/bluetooth/hci_core.c:3832) bluetooth process_one_work (kernel/workqueue.c:2289) worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2437) kthread (kernel/kthread.c:376) ret_from_fork (arch/x86/entry/entry_64.S:306) Freed by task 27920: kasan_save_stack (mm/kasan/common.c:39) kasan_set_track (mm/kasan/common.c:45) kasan_set_free_info (mm/kasan/generic.c:372) ____kasan_slab_free (mm/kasan/common.c:368 mm/kasan/common.c:328) slab_free_freelist_hook (mm/slub.c:1780) kmem_cache_free (mm/slub.c:3536 mm/slub.c:3553) skb_free_datagram (./include/net/sock.h:1578 ./include/net/sock.h:1639 net/core/datagram.c:323) bt_sock_recvmsg (net/bluetooth/af_bluetooth.c:295) bluetooth l2cap_sock_recvmsg (net/bluetooth/l2cap_sock.c:1212) bluetooth sock_read_iter (net/socket.c:1087) new_sync_read (./include/linux/fs.h:2052 fs/read_write.c:401) vfs_read (fs/read_write.c:482) ksys_read (fs/read_write.c:620) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) Link: https://lore.kernel.org/linux-bluetooth/CAKErNvoqga1WcmoR3-0875esY6TVWFQDandbVZncSiuGPBQXLA@mail.gmail.com/T/#u Fixes: d2a7ac5d5d3a ("Bluetooth: Add the ERTM receive state machine") Fixes: 4b51dae96731 ("Bluetooth: Add streaming mode receive and incoming packet classifier") Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
1 parent ba9169f
Tip revision: 3aff8aaca4e36dc8b17eaa011684881a80238966 authored by Maxim Mikityanskiy on 04 October 2022, 21:27:18 UTC
Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu
Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu
Tip revision: 3aff8aa
Kbuild
# SPDX-License-Identifier: GPL-2.0
#
# Kbuild for top-level directory of the kernel
# Prepare global headers and check sanity before descending into sub-directories
# ---------------------------------------------------------------------------
# Generate bounds.h
bounds-file := include/generated/bounds.h
targets := kernel/bounds.s
$(bounds-file): kernel/bounds.s FORCE
$(call filechk,offsets,__LINUX_BOUNDS_H__)
# Generate timeconst.h
timeconst-file := include/generated/timeconst.h
filechk_gentimeconst = echo $(CONFIG_HZ) | bc -q $<
$(timeconst-file): kernel/time/timeconst.bc FORCE
$(call filechk,gentimeconst)
# Generate asm-offsets.h
offsets-file := include/generated/asm-offsets.h
targets += arch/$(SRCARCH)/kernel/asm-offsets.s
arch/$(SRCARCH)/kernel/asm-offsets.s: $(timeconst-file) $(bounds-file)
$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
$(call filechk,offsets,__ASM_OFFSETS_H__)
# Check for missing system calls
quiet_cmd_syscalls = CALL $<
cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)
PHONY += missing-syscalls
missing-syscalls: scripts/checksyscalls.sh $(offsets-file)
$(call cmd,syscalls)
# Check the manual modification of atomic headers
quiet_cmd_check_sha1 = CHKSHA1 $<
cmd_check_sha1 = \
if ! command -v sha1sum >/dev/null; then \
echo "warning: cannot check the header due to sha1sum missing"; \
exit 0; \
fi; \
if [ "$$(sed -n '$$s:// ::p' $<)" != \
"$$(sed '$$d' $< | sha1sum | sed 's/ .*//')" ]; then \
echo "error: $< has been modified." >&2; \
exit 1; \
fi; \
touch $@
atomic-checks += $(addprefix $(obj)/.checked-, \
atomic-arch-fallback.h \
atomic-instrumented.h \
atomic-long.h)
targets += $(atomic-checks)
$(atomic-checks): $(obj)/.checked-%: include/linux/atomic/% FORCE
$(call if_changed,check_sha1)
# A phony target that depends on all the preparation targets
PHONY += prepare
prepare: $(offsets-file) missing-syscalls $(atomic-checks)
@:
# Ordinary directory descending
# ---------------------------------------------------------------------------
obj-y += init/
obj-y += usr/
obj-y += arch/$(SRCARCH)/
obj-y += $(ARCH_CORE)
obj-y += kernel/
obj-y += certs/
obj-y += mm/
obj-y += fs/
obj-y += ipc/
obj-y += security/
obj-y += crypto/
obj-$(CONFIG_BLOCK) += block/
obj-$(CONFIG_IO_URING) += io_uring/
obj-$(CONFIG_RUST) += rust/
obj-y += $(ARCH_LIB)
obj-y += drivers/
obj-y += sound/
obj-$(CONFIG_SAMPLES) += samples/
obj-$(CONFIG_NET) += net/
obj-y += virt/
obj-y += $(ARCH_DRIVERS)
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