9d63b59d1e
When kattr->test.data_size_in > INT_MAX, signed min_t will assign negative value to data_len. This negative value then gets passed over to copy_from_user where it is converted to (big) unsigned. Use unsigned min_t to avoid this overflow. usercopy: Kernel memory overwrite attempt detected to wrapped address (offset 0, size 18446612140539162846)! ------------[ cut here ]------------ kernel BUG at mm/usercopy.c:102! invalid opcode: 0000 [#1] SMP KASAN Modules linked in: CPU: 0 PID: 3781 Comm: syz-executor226 Not tainted 4.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:usercopy_abort+0xbd/0xbf mm/usercopy.c:102 RSP: 0018:ffff8801e9703a38 EFLAGS: 00010286 RAX: 000000000000006c RBX: ffffffff84fc7040 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff816560a2 RDI: ffffed003d2e0739 RBP: ffff8801e9703a90 R08: 000000000000006c R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff84fc73a0 R13: ffffffff84fc7180 R14: ffffffff84fc7040 R15: ffffffff84fc7040 FS: 00007f54e0bec300(0000) GS:ffff8801f6600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000280 CR3: 00000001e90ea000 CR4: 00000000003426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: check_bogus_address mm/usercopy.c:155 [inline] __check_object_size mm/usercopy.c:263 [inline] __check_object_size.cold+0x8c/0xad mm/usercopy.c:253 check_object_size include/linux/thread_info.h:112 [inline] check_copy_size include/linux/thread_info.h:143 [inline] copy_from_user include/linux/uaccess.h:142 [inline] bpf_prog_test_run_xdp+0xe57/0x1240 net/bpf/test_run.c:989 bpf_prog_test_run kernel/bpf/syscall.c:3377 [inline] __sys_bpf+0xdf2/0x4a50 kernel/bpf/syscall.c:4679 SYSC_bpf kernel/bpf/syscall.c:4765 [inline] SyS_bpf+0x26/0x50 kernel/bpf/syscall.c:4763 do_syscall_64+0x21a/0x3e0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x46/0xbb Fixes: 1c1949982524 ("bpf: introduce frags support to bpf_prog_test_run_xdp()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Lorenzo Bianconi <lorenzo@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220204235849.14658-1-sdf@google.com
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.