From c6d308534aef6c99904bf5862066360ae067abc4 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Wed, 20 Jan 2016 15:00:55 -0800 Subject: UBSAN: run-time undefined behavior sanity checker UBSAN uses compile-time instrumentation to catch undefined behavior (UB). Compiler inserts code that perform certain kinds of checks before operations that could cause UB. If check fails (i.e. UB detected) __ubsan_handle_* function called to print error message. So the most of the work is done by compiler. This patch just implements ubsan handlers printing errors. GCC has this capability since 4.9.x [1] (see -fsanitize=undefined option and its suboptions). However GCC 5.x has more checkers implemented [2]. Article [3] has a bit more details about UBSAN in the GCC. [1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html [2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html [3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/ Issues which UBSAN has found thus far are: Found bugs: * out-of-bounds access - 97840cb67ff5 ("netfilter: nfnetlink: fix insufficient validation in nfnetlink_bind") undefined shifts: * d48458d4a768 ("jbd2: use a better hash function for the revoke table") * 10632008b9e1 ("clockevents: Prevent shift out of bounds") * 'x << -1' shift in ext4 - http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com> * undefined rol32(0) - http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com> * undefined dirty_ratelimit calculation - http://lkml.kernel.org/r/<566594E2.3050306@odin.com> * undefined roundown_pow_of_two(0) - http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com> * [WONTFIX] undefined shift in __bpf_prog_run - http://lkml.kernel.org/r/ WONTFIX here because it should be fixed in bpf program, not in kernel. signed overflows: * 32a8df4e0b33f ("sched: Fix odd values in effective_load() calculations") * mul overflow in ntp - http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com> * incorrect conversion into rtc_time in rtc_time64_to_tm() - http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com> * unvalidated timespec in io_getevents() - http://lkml.kernel.org/r/ * [NOTABUG] signed overflow in ktime_add_safe() - http://lkml.kernel.org/r/ [akpm@linux-foundation.org: fix unused local warning] [akpm@linux-foundation.org: fix __int128 build woes] Signed-off-by: Andrey Ryabinin Cc: Peter Zijlstra Cc: Sasha Levin Cc: Randy Dunlap Cc: Rasmus Villemoes Cc: Jonathan Corbet Cc: Michal Marek Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Yury Gribov Cc: Dmitry Vyukov Cc: Konstantin Khlebnikov Cc: Kostya Serebryany Cc: Johannes Berg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/ubsan.h | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 lib/ubsan.h (limited to 'lib/ubsan.h') diff --git a/lib/ubsan.h b/lib/ubsan.h new file mode 100644 index 000000000000..b2d18d4a53f5 --- /dev/null +++ b/lib/ubsan.h @@ -0,0 +1,84 @@ +#ifndef _LIB_UBSAN_H +#define _LIB_UBSAN_H + +enum { + type_kind_int = 0, + type_kind_float = 1, + type_unknown = 0xffff +}; + +struct type_descriptor { + u16 type_kind; + u16 type_info; + char type_name[1]; +}; + +struct source_location { + const char *file_name; + union { + unsigned long reported; + struct { + u32 line; + u32 column; + }; + }; +}; + +struct overflow_data { + struct source_location location; + struct type_descriptor *type; +}; + +struct type_mismatch_data { + struct source_location location; + struct type_descriptor *type; + unsigned long alignment; + unsigned char type_check_kind; +}; + +struct nonnull_arg_data { + struct source_location location; + struct source_location attr_location; + int arg_index; +}; + +struct nonnull_return_data { + struct source_location location; + struct source_location attr_location; +}; + +struct vla_bound_data { + struct source_location location; + struct type_descriptor *type; +}; + +struct out_of_bounds_data { + struct source_location location; + struct type_descriptor *array_type; + struct type_descriptor *index_type; +}; + +struct shift_out_of_bounds_data { + struct source_location location; + struct type_descriptor *lhs_type; + struct type_descriptor *rhs_type; +}; + +struct unreachable_data { + struct source_location location; +}; + +struct invalid_value_data { + struct source_location location; + struct type_descriptor *type; +}; + +#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) +typedef __int128 s_max; +typedef unsigned __int128 u_max; +#else +typedef s64 s_max; +typedef u64 u_max; +#endif + +#endif -- cgit v1.2.1