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[ Upstream commit f88b4c01b97e09535505cf3c327fdbce55c27f00 ] netlbl_unlabel_addrinfo_get() assumes that if it finds the NLBL_UNLABEL_A_IPV4ADDR attribute, it must also have the NLBL_UNLABEL_A_IPV4MASK attribute as well. However, this is not necessarily the case as the current checks in netlbl_unlabel_staticadd() and friends are not sufficent to enforce this. If passed a netlink message with NLBL_UNLABEL_A_IPV4ADDR, NLBL_UNLABEL_A_IPV6ADDR, and NLBL_UNLABEL_A_IPV6MASK attributes, these functions will all call netlbl_unlabel_addrinfo_get() which will then attempt dereference NULL when fetching the non-existent NLBL_UNLABEL_A_IPV4MASK attribute: Unable to handle kernel NULL pointer dereference at virtual address 0 Process unlab (pid: 31762, stack limit = 0xffffff80502d8000) Call trace: netlbl_unlabel_addrinfo_get+0x44/0xd8 netlbl_unlabel_staticremovedef+0x98/0xe0 genl_rcv_msg+0x354/0x388 netlink_rcv_skb+0xac/0x118 genl_rcv+0x34/0x48 netlink_unicast+0x158/0x1f0 netlink_sendmsg+0x32c/0x338 sock_sendmsg+0x44/0x60 ___sys_sendmsg+0x1d0/0x2a8 __sys_sendmsg+0x64/0xb4 SyS_sendmsg+0x34/0x4c el0_svc_naked+0x34/0x38 Code: 51001149 7100113f 540000a0 f9401508 (79400108) ---[ end trace f6438a488e737143 ]--- Kernel panic - not syncing: Fatal exception Signed-off-by: Sean Tranchetti <stranche@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.