3afb096188
Apparently a refactoring patch brought a bug, that was caught by syzbot [1] Original code was correct, do not try to be smarter than the compiler :/ [1] BUG: KASAN: slab-out-of-bounds in tcp_zerocopy_receive net/ipv4/tcp.c:1807 [inline] BUG: KASAN: slab-out-of-bounds in do_tcp_getsockopt.isra.0+0x2c6c/0x3120 net/ipv4/tcp.c:3654 Read of size 4 at addr ffff8880943cf188 by task syz-executor.2/17508 CPU: 0 PID: 17508 Comm: syz-executor.2 Not tainted 5.3.0-rc7+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x17 mm/kasan/common.c:618 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 tcp_zerocopy_receive net/ipv4/tcp.c:1807 [inline] do_tcp_getsockopt.isra.0+0x2c6c/0x3120 net/ipv4/tcp.c:3654 tcp_getsockopt+0xbf/0xe0 net/ipv4/tcp.c:3680 sock_common_getsockopt+0x94/0xd0 net/core/sock.c:3098 __sys_getsockopt+0x16d/0x310 net/socket.c:2129 __do_sys_getsockopt net/socket.c:2144 [inline] __se_sys_getsockopt net/socket.c:2141 [inline] __x64_sys_getsockopt+0xbe/0x150 net/socket.c:2141 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 Fixes: d8e18a516f8f ("net: Use skb accessors in network core") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.