From: Jakub Jelinek Date: Fri, 1 Oct 2021 12:27:32 +0000 (+0200) Subject: ubsan: Move INT_MIN / -1 instrumentation from -fsanitize=integer-divide-by-zero to... X-Git-Tag: basepoints/gcc-13~4271 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9c1a633d96926357155d4702b66f8a0ec856a81f;p=thirdparty%2Fgcc.git ubsan: Move INT_MIN / -1 instrumentation from -fsanitize=integer-divide-by-zero to -fsanitize=signed-integer-overflow [PR102515] As noted by Richi, in clang INT_MIN / -1 is instrumented under -fsanitize=signed-integer-overflow rather than -fsanitize=integer-divide-by-zero as we did and doing it in the former makes more sense, as it is overflow during division rather than division by zero. I've verified on godbolt that clang behaved that way since 3.2-ish times or so when sanitizers were added. Furthermore, we've been using -f{,no-}sanitize-recover=integer-divide-by-zero to decide on the float -fsanitize=float-divide-by-zero instrumentation _abort suffix. The case where INT_MIN / -1 is instrumented by one sanitizer and x / 0 by another one when both are enabled is slightly harder if the -f{,no-}sanitize-recover={integer-divide-by-zero,signed-integer-overflow} flags differ, then we need to emit both __ubsan_handle_divrem_overflow and __ubsan_handle_divrem_overflow_abort calls guarded by their respective checks rather than one guarded by check1 || check2. 2021-10-01 Jakub Jelinek Richard Biener PR sanitizer/102515 gcc/ * doc/invoke.texi (-fsanitize=integer-divide-by-zero): Remove INT_MIN / -1 division detection from here ... (-fsanitize=signed-integer-overflow): ... and add it here. gcc/c-family/ * c-ubsan.c (ubsan_instrument_division): Check the right flag_sanitize_recover bit, depending on which sanitization is done. Sanitize INT_MIN / -1 under SANITIZE_SI_OVERFLOW rather than SANITIZE_DIVIDE. If both SANITIZE_SI_OVERFLOW and SANITIZE_DIVIDE is enabled, neither check is known to be false and flag_sanitize_recover bits for those two aren't the same, emit both __ubsan_handle_divrem_overflow and __ubsan_handle_divrem_overflow_abort calls. gcc/c/ * c-typeck.c (build_binary_op): Call ubsan_instrument_division for division even for SANITIZE_SI_OVERFLOW. gcc/cp/ * typeck.c (cp_build_binary_op): Call ubsan_instrument_division for division even for SANITIZE_SI_OVERFLOW. gcc/testsuite/ * c-c++-common/ubsan/div-by-zero-3.c: Use -fsanitize=signed-integer-overflow instead of -fsanitize=integer-divide-by-zero. * c-c++-common/ubsan/div-by-zero-5.c: Likewise. * c-c++-common/ubsan/div-by-zero-4.c: Likewise. Add -fsanitize-undefined-trap-on-error. * c-c++-common/ubsan/float-div-by-zero-2.c: New test. * c-c++-common/ubsan/overflow-div-1.c: New test. * c-c++-common/ubsan/overflow-div-2.c: New test. * c-c++-common/ubsan/overflow-div-3.c: New test. --- diff --git a/gcc/c-family/c-ubsan.c b/gcc/c-family/c-ubsan.c index 12a7bca5c32e..a4509c68c16d 100644 --- a/gcc/c-family/c-ubsan.c +++ b/gcc/c-family/c-ubsan.c @@ -39,8 +39,9 @@ along with GCC; see the file COPYING3. If not see tree ubsan_instrument_division (location_t loc, tree op0, tree op1) { - tree t, tt; + tree t, tt, x = NULL_TREE; tree type = TREE_TYPE (op0); + enum sanitize_code flag = SANITIZE_DIVIDE; /* At this point both operands should have the same type, because they are already converted to RESULT_TYPE. @@ -58,24 +59,42 @@ ubsan_instrument_division (location_t loc, tree op0, tree op1) op1, build_int_cst (type, 0)); else if (TREE_CODE (type) == REAL_TYPE && sanitize_flags_p (SANITIZE_FLOAT_DIVIDE)) - t = fold_build2 (EQ_EXPR, boolean_type_node, - op1, build_real (type, dconst0)); + { + t = fold_build2 (EQ_EXPR, boolean_type_node, + op1, build_real (type, dconst0)); + flag = SANITIZE_FLOAT_DIVIDE; + } else - return NULL_TREE; + t = NULL_TREE; /* We check INT_MIN / -1 only for signed types. */ if (TREE_CODE (type) == INTEGER_TYPE - && sanitize_flags_p (SANITIZE_DIVIDE) + && sanitize_flags_p (SANITIZE_SI_OVERFLOW) && !TYPE_UNSIGNED (type)) { - tree x; tt = fold_build2 (EQ_EXPR, boolean_type_node, unshare_expr (op1), build_int_cst (type, -1)); x = fold_build2 (EQ_EXPR, boolean_type_node, op0, TYPE_MIN_VALUE (type)); x = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, x, tt); - t = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t, x); + if (t == NULL_TREE || integer_zerop (t)) + { + t = x; + x = NULL_TREE; + flag = SANITIZE_SI_OVERFLOW; + } + else if (flag_sanitize_undefined_trap_on_error + || (((flag_sanitize_recover & SANITIZE_DIVIDE) == 0) + == ((flag_sanitize_recover & SANITIZE_SI_OVERFLOW) == 0))) + { + t = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t, x); + x = NULL_TREE; + } + else if (integer_zerop (x)) + x = NULL_TREE; } + else if (t == NULL_TREE) + return NULL_TREE; /* If the condition was folded to 0, no need to instrument this expression. */ @@ -95,7 +114,7 @@ ubsan_instrument_division (location_t loc, tree op0, tree op1) NULL_TREE); data = build_fold_addr_expr_loc (loc, data); enum built_in_function bcode - = (flag_sanitize_recover & SANITIZE_DIVIDE) + = (flag_sanitize_recover & flag) ? BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW : BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW_ABORT; tt = builtin_decl_explicit (bcode); @@ -103,8 +122,20 @@ ubsan_instrument_division (location_t loc, tree op0, tree op1) op1 = unshare_expr (op1); tt = build_call_expr_loc (loc, tt, 3, data, ubsan_encode_value (op0), ubsan_encode_value (op1)); + if (x) + { + bcode = (flag_sanitize_recover & SANITIZE_SI_OVERFLOW) + ? BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW + : BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW_ABORT; + tree xt = builtin_decl_explicit (bcode); + op0 = unshare_expr (op0); + op1 = unshare_expr (op1); + xt = build_call_expr_loc (loc, xt, 3, data, ubsan_encode_value (op0), + ubsan_encode_value (op1)); + x = fold_build3 (COND_EXPR, void_type_node, x, xt, void_node); + } } - t = fold_build3 (COND_EXPR, void_type_node, t, tt, void_node); + t = fold_build3 (COND_EXPR, void_type_node, t, tt, x ? x : void_node); return t; } diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c index b472e448011e..c74f876e6674 100644 --- a/gcc/c/c-typeck.c +++ b/gcc/c/c-typeck.c @@ -12733,7 +12733,9 @@ build_binary_op (location_t location, enum tree_code code, } if (sanitize_flags_p ((SANITIZE_SHIFT - | SANITIZE_DIVIDE | SANITIZE_FLOAT_DIVIDE)) + | SANITIZE_DIVIDE + | SANITIZE_FLOAT_DIVIDE + | SANITIZE_SI_OVERFLOW)) && current_function_decl != NULL_TREE && (doing_div_or_mod || doing_shift) && !require_constant_value) @@ -12744,7 +12746,8 @@ build_binary_op (location_t location, enum tree_code code, op0 = c_fully_fold (op0, false, NULL); op1 = c_fully_fold (op1, false, NULL); if (doing_div_or_mod && (sanitize_flags_p ((SANITIZE_DIVIDE - | SANITIZE_FLOAT_DIVIDE)))) + | SANITIZE_FLOAT_DIVIDE + | SANITIZE_SI_OVERFLOW)))) instrument_expr = ubsan_instrument_division (location, op0, op1); else if (doing_shift && sanitize_flags_p (SANITIZE_SHIFT)) instrument_expr = ubsan_instrument_shift (location, code, op0, op1); diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c index a2398dbe660c..cd130f16a66b 100644 --- a/gcc/cp/typeck.c +++ b/gcc/cp/typeck.c @@ -6038,7 +6038,9 @@ cp_build_binary_op (const op_location_t &location, } if (sanitize_flags_p ((SANITIZE_SHIFT - | SANITIZE_DIVIDE | SANITIZE_FLOAT_DIVIDE)) + | SANITIZE_DIVIDE + | SANITIZE_FLOAT_DIVIDE + | SANITIZE_SI_OVERFLOW)) && current_function_decl != NULL_TREE && !processing_template_decl && (doing_div_or_mod || doing_shift)) @@ -6050,7 +6052,9 @@ cp_build_binary_op (const op_location_t &location, op1 = fold_non_dependent_expr (op1, complain); tree instrument_expr1 = NULL_TREE; if (doing_div_or_mod - && sanitize_flags_p (SANITIZE_DIVIDE | SANITIZE_FLOAT_DIVIDE)) + && sanitize_flags_p (SANITIZE_DIVIDE + | SANITIZE_FLOAT_DIVIDE + | SANITIZE_SI_OVERFLOW)) { /* For diagnostics we want to use the promoted types without shorten_binary_op. So convert the arguments to the diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index d0198d77434d..5f39b208049b 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -15229,7 +15229,7 @@ ISO C90 and C99, etc. @item -fsanitize=integer-divide-by-zero @opindex fsanitize=integer-divide-by-zero -Detect integer division by zero as well as @code{INT_MIN / -1} division. +Detect integer division by zero. @item -fsanitize=unreachable @opindex fsanitize=unreachable @@ -15261,7 +15261,8 @@ returning a value. This option works in C++ only. @opindex fsanitize=signed-integer-overflow This option enables signed integer overflow checking. We check that the result of @code{+}, @code{*}, and both unary and binary @code{-} -does not overflow in the signed arithmetics. Note, integer promotion +does not overflow in the signed arithmetics. This also detects +@code{INT_MIN / -1} signed division. Note, integer promotion rules must be taken into account. That is, the following is not an overflow: @smallexample diff --git a/gcc/testsuite/c-c++-common/ubsan/div-by-zero-3.c b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-3.c index 266423aa49ff..1d51e3573e76 100644 --- a/gcc/testsuite/c-c++-common/ubsan/div-by-zero-3.c +++ b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-3.c @@ -1,5 +1,5 @@ /* { dg-do run } */ -/* { dg-options "-fsanitize=integer-divide-by-zero -Wno-overflow" } */ +/* { dg-options "-fsanitize=signed-integer-overflow -Wno-overflow" } */ #include diff --git a/gcc/testsuite/c-c++-common/ubsan/div-by-zero-4.c b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-4.c index 02162e139e30..ef431c93e4e2 100644 --- a/gcc/testsuite/c-c++-common/ubsan/div-by-zero-4.c +++ b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-4.c @@ -1,5 +1,5 @@ /* { dg-do run } */ -/* { dg-options "-fsanitize=integer-divide-by-zero -Wno-overflow" } */ +/* { dg-options "-fsanitize=signed-integer-overflow -fsanitize-undefined-trap-on-error -Wno-overflow" } */ #define INT_MIN (-__INT_MAX__ - 1) diff --git a/gcc/testsuite/c-c++-common/ubsan/div-by-zero-5.c b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-5.c index bb391c5b36df..853a3dc50035 100644 --- a/gcc/testsuite/c-c++-common/ubsan/div-by-zero-5.c +++ b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-5.c @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-fsanitize=integer-divide-by-zero" } */ +/* { dg-options "-fsanitize=signed-integer-overflow" } */ void foo (void) diff --git a/gcc/testsuite/c-c++-common/ubsan/float-div-by-zero-2.c b/gcc/testsuite/c-c++-common/ubsan/float-div-by-zero-2.c new file mode 100644 index 000000000000..61d050ae23be --- /dev/null +++ b/gcc/testsuite/c-c++-common/ubsan/float-div-by-zero-2.c @@ -0,0 +1,18 @@ +/* { dg-do run } */ +/* { dg-shouldfail "ubsan" } */ +/* { dg-options "-fsanitize=float-divide-by-zero -fno-sanitize-recover=float-divide-by-zero -fsanitize-recover=integer-divide-by-zero" } */ + +int +main (void) +{ + volatile float a = 1.3f; + volatile double b = 0.0; + volatile int c = 4; + volatile float res; + + res = a / b; + + return 0; +} + +/* { dg-output "division by zero" } */ diff --git a/gcc/testsuite/c-c++-common/ubsan/overflow-div-1.c b/gcc/testsuite/c-c++-common/ubsan/overflow-div-1.c new file mode 100644 index 000000000000..d781660f4ff0 --- /dev/null +++ b/gcc/testsuite/c-c++-common/ubsan/overflow-div-1.c @@ -0,0 +1,17 @@ +/* { dg-do run } */ +/* { dg-options "-fsanitize=integer-divide-by-zero -fno-sanitize-recover=undefined,float-divide-by-zero -Wno-overflow" } */ + +#include + +int +main (void) +{ + volatile int min = INT_MIN; + volatile int zero = 0; + + INT_MIN / -1; + min / -1; + min / (10 * zero - (2 - 1)); + + return 0; +} diff --git a/gcc/testsuite/c-c++-common/ubsan/overflow-div-2.c b/gcc/testsuite/c-c++-common/ubsan/overflow-div-2.c new file mode 100644 index 000000000000..dfef1b0145e3 --- /dev/null +++ b/gcc/testsuite/c-c++-common/ubsan/overflow-div-2.c @@ -0,0 +1,41 @@ +/* { dg-do run { target *-*-linux* *-*-gnu* } } */ +/* { dg-shouldfail "ubsan" } */ +/* { dg-options "-fsanitize=undefined -fno-sanitize-recover=integer-divide-by-zero" } */ + +#include +#include +#include + +int cnt; + +__attribute__((noipa)) int +foo (int x, int y) +{ + return x / y; +} + +void +handler (int i) +{ + if (cnt++ != 0) + exit (0); + volatile int b = foo (5, 0); + exit (0); +} + +int +main (void) +{ + struct sigaction s; + sigemptyset (&s.sa_mask); + s.sa_handler = handler; + s.sa_flags = 0; + sigaction (SIGFPE, &s, NULL); + volatile int a = foo (INT_MIN, -1); + cnt++; + volatile int b = foo (5, 0); + return 0; +} + +/* { dg-output "division of -2147483648 by -1 cannot be represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */ +/* { dg-output "\[^\n\r]*division by zero\[^\n\r]*" } */ diff --git a/gcc/testsuite/c-c++-common/ubsan/overflow-div-3.c b/gcc/testsuite/c-c++-common/ubsan/overflow-div-3.c new file mode 100644 index 000000000000..479dffb03044 --- /dev/null +++ b/gcc/testsuite/c-c++-common/ubsan/overflow-div-3.c @@ -0,0 +1,41 @@ +/* { dg-do run { target *-*-linux* *-*-gnu* } } */ +/* { dg-shouldfail "ubsan" } */ +/* { dg-options "-fsanitize=undefined -fno-sanitize-recover=signed-integer-overflow" } */ + +#include +#include +#include + +int cnt; + +__attribute__((noipa)) int +foo (int x, int y) +{ + return x / y; +} + +void +handler (int i) +{ + if (cnt++ != 0) + exit (0); + volatile int b = foo (INT_MIN, -1); + exit (0); +} + +int +main (void) +{ + struct sigaction s; + sigemptyset (&s.sa_mask); + s.sa_handler = handler; + s.sa_flags = 0; + sigaction (SIGFPE, &s, NULL); + volatile int a = foo (42, 0); + cnt++; + volatile int b = foo (INT_MIN, -1); + return 0; +} + +/* { dg-output "division by zero\[^\n\r]*(\n|\r\n|\r)" } */ +/* { dg-output "\[^\n\r]*division of -2147483648 by -1 cannot be represented in type 'int'" } */