CVE-2022-49908: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix memory leak in vhci_write Syzkaller reports a memory leak as follows…

PriorityP419medium5.5CVSS 3.1

AVLACLPRLUINSUCNINAH

EPSS

0.19%

8.4th percentile

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix memory leak in vhci_write Syzkaller reports a memory leak as follows: BUG: memory leak unreferenced object 0xffff88810d81ac00 (size 240): [...] hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418 [] alloc_skb include/linux/skbuff.h:1257 [inline] [] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline] [] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline] [] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511 [] call_write_iter include/linux/fs.h:2192 [inline] [] new_sync_write fs/read_write.c:491 [inline] [] vfs_write+0x42d/0x540 fs/read_write.c:578 [] ksys_write+0x9d/0x160 fs/read_write.c:631 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x63/0xcd HCI core will uses hci_rx_work() to process frame, which is queued to the hdev->rx_q tail in hci_recv_frame() by HCI driver. Yet the problem is that, HCI core may not free the skb after handling ACL data packets. To be more specific, when start fragment does not contain the L2CAP length, HCI core just copies skb into conn->rx_skb and finishes frame process in l2cap_recv_acldata(), without freeing the skb, which triggers the above memory leak. This patch solves it by releasing the relative skb, after processing the above case in l2cap_recv_acldata().

Affected

11 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.0.8-1 (bookworm)	linux 6.0.8-1 (bookworm)
linux	linux	—	—
linux	linux	>= 4d7ea8ee90e42fc75995f6fb24032d3233314528 < aa16cac06b752e5f609c106735bd7838f444784c	aa16cac06b752e5f609c106735bd7838f444784c
linux	linux	>= 4d7ea8ee90e42fc75995f6fb24032d3233314528 < 5b4f039a2f487c5edae681d763fe1af505f84c13	5b4f039a2f487c5edae681d763fe1af505f84c13
linux	linux	>= 4d7ea8ee90e42fc75995f6fb24032d3233314528 < 7c9524d929648935bac2bbb4c20437df8f9c3f42	7c9524d929648935bac2bbb4c20437df8f9c3f42
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 6.0.8-1	6.0.8-1
linux	linux_kernel	>= 0 < 6.0.8-1	6.0.8-1
linux	linux_kernel	>= 0 < 6.0.8-1	6.0.8-1
linux	linux_kernel	>= 5.12 < 5.15.78	5.15.78
linux	linux_kernel	>= 5.16 < 6.0.8	6.0.8

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv5.5MEDIUM

vendor_debian5.5MEDIUM

vendor_redhat5.5MEDIUM

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