1. 03 4月, 2018 33 次提交
  2. 26 3月, 2018 1 次提交
  3. 06 3月, 2018 2 次提交
  4. 05 3月, 2018 2 次提交
  5. 03 3月, 2018 1 次提交
    • M
      signals: Move put_compat_sigset to compat.h to silence hardened usercopy · fde9fc76
      Matt Redfearn 提交于
      Since commit afcc90f8 ("usercopy: WARN() on slab cache usercopy
      region violations"), MIPS systems booting with a compat root filesystem
      emit a warning when copying compat siginfo to userspace:
      
      WARNING: CPU: 0 PID: 953 at mm/usercopy.c:81 usercopy_warn+0x98/0xe8
      Bad or missing usercopy whitelist? Kernel memory exposure attempt
      detected from SLAB object 'task_struct' (offset 1432, size 16)!
      Modules linked in:
      CPU: 0 PID: 953 Comm: S01logging Not tainted 4.16.0-rc2 #10
      Stack : ffffffff808c0000 0000000000000000 0000000000000001 65ac85163f3bdc4a
      	65ac85163f3bdc4a 0000000000000000 90000000ff667ab8 ffffffff808c0000
      	00000000000003f8 ffffffff808d0000 00000000000000d1 0000000000000000
      	000000000000003c 0000000000000000 ffffffff808c8ca8 ffffffff808d0000
      	ffffffff808d0000 ffffffff80810000 fffffc0000000000 ffffffff80785c30
      	0000000000000009 0000000000000051 90000000ff667eb0 90000000ff667db0
      	000000007fe0d938 0000000000000018 ffffffff80449958 0000000020052798
      	ffffffff808c0000 90000000ff664000 90000000ff667ab0 00000000100c0000
      	ffffffff80698810 0000000000000000 0000000000000000 0000000000000000
      	0000000000000000 0000000000000000 ffffffff8010d02c 65ac85163f3bdc4a
      	...
      Call Trace:
      [<ffffffff8010d02c>] show_stack+0x9c/0x130
      [<ffffffff80698810>] dump_stack+0x90/0xd0
      [<ffffffff80137b78>] __warn+0x100/0x118
      [<ffffffff80137bdc>] warn_slowpath_fmt+0x4c/0x70
      [<ffffffff8021e4a8>] usercopy_warn+0x98/0xe8
      [<ffffffff8021e68c>] __check_object_size+0xfc/0x250
      [<ffffffff801bbfb8>] put_compat_sigset+0x30/0x88
      [<ffffffff8011af24>] setup_rt_frame_n32+0xc4/0x160
      [<ffffffff8010b8b4>] do_signal+0x19c/0x230
      [<ffffffff8010c408>] do_notify_resume+0x60/0x78
      [<ffffffff80106f50>] work_notifysig+0x10/0x18
      ---[ end trace 88fffbf69147f48a ]---
      
      Commit 5905429a ("fork: Provide usercopy whitelisting for
      task_struct") noted that:
      
      "While the blocked and saved_sigmask fields of task_struct are copied to
      userspace (via sigmask_to_save() and setup_rt_frame()), it is always
      copied with a static length (i.e. sizeof(sigset_t))."
      
      However, this is not true in the case of compat signals, whose sigset
      is copied by put_compat_sigset and receives size as an argument.
      
      At most call sites, put_compat_sigset is copying a sigset from the
      current task_struct. This triggers a warning when
      CONFIG_HARDENED_USERCOPY is active. However, by marking this function as
      static inline, the warning can be avoided because in all of these cases
      the size is constant at compile time, which is allowed. The only site
      where this is not the case is handling the rt_sigpending syscall, but
      there the copy is being made from a stack local variable so does not
      trigger the warning.
      
      Move put_compat_sigset to compat.h, and mark it static inline. This
      fixes the WARN on MIPS.
      
      Fixes: afcc90f8 ("usercopy: WARN() on slab cache usercopy region violations")
      Signed-off-by: NMatt Redfearn <matt.redfearn@mips.com>
      Acked-by: NKees Cook <keescook@chromium.org>
      Cc: "Dmitry V . Levin" <ldv@altlinux.org>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: kernel-hardening@lists.openwall.com
      Cc: linux-mips@linux-mips.org
      Patchwork: https://patchwork.linux-mips.org/patch/18639/Signed-off-by: NJames Hogan <jhogan@kernel.org>
      fde9fc76
  6. 01 3月, 2018 1 次提交