ecb4534b6a
kernel test robot reported slab-out-of-bounds access in strlen(). [0] Commit06d4c8a808("af_unix: Fix fortify_panic() in unix_bind_bsd().") removed unix_mkname_bsd() call in unix_bind_bsd(). If sunaddr->sun_path is not terminated by user and we don't enable CONFIG_INIT_STACK_ALL_ZERO=y, strlen() will do the out-of-bounds access during file creation. Let's go back to strlen()-with-sockaddr_storage way and pack all 108 trickiness into unix_mkname_bsd() with bold comments. [0]: BUG: KASAN: slab-out-of-bounds in strlen (lib/string.c:?) Read of size 1 at addr ffff000015492777 by task fortify_strlen_/168 CPU: 0 PID: 168 Comm: fortify_strlen_ Not tainted 6.5.0-rc1-00333-g3329b603ebba #16 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace (arch/arm64/kernel/stacktrace.c:235) show_stack (arch/arm64/kernel/stacktrace.c:242) dump_stack_lvl (lib/dump_stack.c:107) print_report (mm/kasan/report.c:365 mm/kasan/report.c:475) kasan_report (mm/kasan/report.c:590) __asan_report_load1_noabort (mm/kasan/report_generic.c:378) strlen (lib/string.c:?) getname_kernel (./include/linux/fortify-string.h:? fs/namei.c:226) kern_path_create (fs/namei.c:3926) unix_bind (net/unix/af_unix.c:1221 net/unix/af_unix.c:1324) __sys_bind (net/socket.c:1792) __arm64_sys_bind (net/socket.c:1801) invoke_syscall (arch/arm64/kernel/syscall.c:? arch/arm64/kernel/syscall.c:52) el0_svc_common (./include/linux/thread_info.h:127 arch/arm64/kernel/syscall.c:147) do_el0_svc (arch/arm64/kernel/syscall.c:189) el0_svc (./arch/arm64/include/asm/daifflags.h:28 arch/arm64/kernel/entry-common.c:133 arch/arm64/kernel/entry-common.c:144 arch/arm64/kernel/entry-common.c:648) el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:?) el0t_64_sync (arch/arm64/kernel/entry.S:591) Allocated by task 168: kasan_set_track (mm/kasan/common.c:45 mm/kasan/common.c:52) kasan_save_alloc_info (mm/kasan/generic.c:512) __kasan_kmalloc (mm/kasan/common.c:383) __kmalloc (mm/slab_common.c:? mm/slab_common.c:998) unix_bind (net/unix/af_unix.c:257 net/unix/af_unix.c:1213 net/unix/af_unix.c:1324) __sys_bind (net/socket.c:1792) __arm64_sys_bind (net/socket.c:1801) invoke_syscall (arch/arm64/kernel/syscall.c:? arch/arm64/kernel/syscall.c:52) el0_svc_common (./include/linux/thread_info.h:127 arch/arm64/kernel/syscall.c:147) do_el0_svc (arch/arm64/kernel/syscall.c:189) el0_svc (./arch/arm64/include/asm/daifflags.h:28 arch/arm64/kernel/entry-common.c:133 arch/arm64/kernel/entry-common.c:144 arch/arm64/kernel/entry-common.c:648) el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:?) el0t_64_sync (arch/arm64/kernel/entry.S:591) The buggy address belongs to the object at ffff000015492700 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes to the right of allocated 119-byte region [ffff000015492700, ffff000015492777) The buggy address belongs to the physical page: page:00000000aeab52ba refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x55492 anon flags: 0x3fffc0000000200(slab|node=0|zone=0|lastcpupid=0xffff) page_type: 0xffffffff() raw: 03fffc0000000200 ffff0000084018c0 fffffc00003d0e00 0000000000000005 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff000015492600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff000015492680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff000015492700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 07 fc ^ ffff000015492780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff000015492800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Fixes:06d4c8a808("af_unix: Fix fortify_panic() in unix_bind_bsd().") Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/netdev/202307262110.659e5e8-oliver.sang@intel.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230726190828.47874-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.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.