Michal Luczaj d0a3b3d117 bpf: Fix bpf_sk_select_reuseport() memory leak
[ Upstream commit b3af60928ab9129befa65e6df0310d27300942bf ]

As pointed out in the original comment, lookup in sockmap can return a TCP
ESTABLISHED socket. Such TCP socket may have had SO_ATTACH_REUSEPORT_EBPF
set before it was ESTABLISHED. In other words, a non-NULL sk_reuseport_cb
does not imply a non-refcounted socket.

Drop sk's reference in both error paths.

unreferenced object 0xffff888101911800 (size 2048):
  comm "test_progs", pid 44109, jiffies 4297131437
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    80 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 9336483b):
    __kmalloc_noprof+0x3bf/0x560
    __reuseport_alloc+0x1d/0x40
    reuseport_alloc+0xca/0x150
    reuseport_attach_prog+0x87/0x140
    sk_reuseport_attach_bpf+0xc8/0x100
    sk_setsockopt+0x1181/0x1990
    do_sock_setsockopt+0x12b/0x160
    __sys_setsockopt+0x7b/0xc0
    __x64_sys_setsockopt+0x1b/0x30
    do_syscall_64+0x93/0x180
    entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fixes: 64d85290d7 ("bpf: Allow bpf_map_lookup_elem for SOCKMAP and SOCKHASH")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250110-reuseport-memleak-v1-1-fa1ddab0adfe@rbox.co
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-01-23 17:17:09 +01:00
2024-12-14 19:53:51 +01:00
2024-12-14 19:54:40 +01:00
2022-09-28 09:02:20 +02:00
2025-01-19 09:01:16 +01:00

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.

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.
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