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Eric Biggers
5fdb551fd6
[ Upstream commitff7b11aa48] Commit9060cb719e("net: crypto set sk to NULL when af_alg_release.") fixed a use-after-free in sockfs_setattr() when an AF_ALG socket is closed concurrently with fchownat(). However, it ignored that many other proto_ops::release() methods don't set sock->sk to NULL and therefore allow the same use-after-free: - base_sock_release - bnep_sock_release - cmtp_sock_release - data_sock_release - dn_release - hci_sock_release - hidp_sock_release - iucv_sock_release - l2cap_sock_release - llcp_sock_release - llc_ui_release - rawsock_release - rfcomm_sock_release - sco_sock_release - svc_release - vcc_release - x25_release Rather than fixing all these and relying on every socket type to get this right forever, just make __sock_release() set sock->sk to NULL itself after calling proto_ops::release(). Reproducer that produces the KASAN splat when any of these socket types are configured into the kernel: #include <pthread.h> #include <stdlib.h> #include <sys/socket.h> #include <unistd.h> pthread_t t; volatile int fd; void *close_thread(void *arg) { for (;;) { usleep(rand() % 100); close(fd); } } int main() { pthread_create(&t, NULL, close_thread, NULL); for (;;) { fd = socket(rand() % 50, rand() % 11, 0); fchownat(fd, "", 1000, 1000, 0x1000); close(fd); } } Fixes:86741ec254("net: core: Add a UID field to struct sock.") Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
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.