lkml.org 
[lkml]   [2019]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 14/25] x86/uaccess,ubsan: Fix UBSAN vs SMAP
    UBSAN can insert extra code in random locations; including AC=1
    sections. Typically this code is not safe and needs wrapping.

    So far, only __ubsan_handle_type_mismatch* have been observed in AC=1
    sections and therefore only those are annotated.

    Cc: Dmitry Vyukov <dvyukov@google.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    ---
    lib/Makefile | 1 +
    lib/ubsan.c | 4 ++++
    2 files changed, 5 insertions(+)

    --- a/lib/Makefile
    +++ b/lib/Makefile
    @@ -263,6 +263,7 @@ obj-$(CONFIG_UCS2_STRING) += ucs2_string
    obj-$(CONFIG_UBSAN) += ubsan.o

    UBSAN_SANITIZE_ubsan.o := n
    +CFLAGS_ubsan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)

    obj-$(CONFIG_SBITMAP) += sbitmap.o

    --- a/lib/ubsan.c
    +++ b/lib/ubsan.c
    @@ -17,6 +17,7 @@
    #include <linux/kernel.h>
    #include <linux/types.h>
    #include <linux/sched.h>
    +#include <linux/uaccess.h>

    #include "ubsan.h"

    @@ -313,6 +314,7 @@ static void handle_object_size_mismatch(
    static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
    unsigned long ptr)
    {
    + unsigned long flags = user_access_save();

    if (!ptr)
    handle_null_ptr_deref(data);
    @@ -320,6 +322,8 @@ static void ubsan_type_mismatch_common(s
    handle_misaligned_access(data, ptr);
    else
    handle_object_size_mismatch(data, ptr);
    +
    + user_access_restore(flags);
    }

    void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,

    \
     
     \ /
      Last update: 2019-03-18 16:54    [W:6.349 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site