tools: bpf: make use of reallocarray
reallocarray() is a safer variant of realloc which checks for multiplication overflow in case of array allocation. Since it's not available in Glibc < 2.26 import kernel's overflow.h and add a static inline implementation when needed. Use feature detection to probe for existence of reallocarray. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>hifive-unleashed-5.1
Jakub Kicinski
Daniel Borkmann
parent
8d13406c02
commit
531b014e7a
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@ -52,7 +52,7 @@ INSTALL ?= install
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RM ?= rm -f
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FEATURE_USER = .bpftool
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FEATURE_TESTS = libbfd disassembler-four-args
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FEATURE_TESTS = libbfd disassembler-four-args reallocarray
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FEATURE_DISPLAY = libbfd disassembler-four-args
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check_feat := 1
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@ -75,6 +75,10 @@ ifeq ($(feature-disassembler-four-args), 1)
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CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
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endif
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ifeq ($(feature-reallocarray), 0)
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CFLAGS += -DCOMPAT_NEED_REALLOCARRAY
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endif
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include $(wildcard $(OUTPUT)*.d)
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all: $(OUTPUT)bpftool
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@ -42,6 +42,7 @@
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#include <linux/compiler.h>
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#include <linux/kernel.h>
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#include <linux/hashtable.h>
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#include <tools/libc_compat.h>
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#include "json_writer.h"
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@ -35,6 +35,7 @@
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#define _GNU_SOURCE
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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@ -66,9 +67,8 @@ void kernel_syms_load(struct dump_data *dd)
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while (!feof(fp)) {
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if (!fgets(buff, sizeof(buff), fp))
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break;
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tmp = realloc(dd->sym_mapping,
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(dd->sym_count + 1) *
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sizeof(*dd->sym_mapping));
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tmp = reallocarray(dd->sym_mapping, dd->sym_count + 1,
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sizeof(*dd->sym_mapping));
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if (!tmp) {
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out:
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free(dd->sym_mapping);
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@ -14,6 +14,7 @@ FILES= \
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test-libaudit.bin \
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test-libbfd.bin \
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test-disassembler-four-args.bin \
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test-reallocarray.bin \
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test-liberty.bin \
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test-liberty-z.bin \
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test-cplus-demangle.bin \
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@ -204,6 +205,9 @@ $(OUTPUT)test-libbfd.bin:
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$(OUTPUT)test-disassembler-four-args.bin:
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$(BUILD) -DPACKAGE='"perf"' -lbfd -lopcodes
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$(OUTPUT)test-reallocarray.bin:
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$(BUILD)
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$(OUTPUT)test-liberty.bin:
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$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
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@ -0,0 +1,8 @@
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// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <stdlib.h>
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int main(void)
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{
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return !!reallocarray(NULL, 1, 1);
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}
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@ -36,3 +36,7 @@
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#endif
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#define __printf(a, b) __attribute__((format(printf, a, b)))
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#define __scanf(a, b) __attribute__((format(scanf, a, b)))
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#if GCC_VERSION >= 50100
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#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
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#endif
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@ -0,0 +1,278 @@
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/* SPDX-License-Identifier: GPL-2.0 OR MIT */
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#ifndef __LINUX_OVERFLOW_H
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#define __LINUX_OVERFLOW_H
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#include <linux/compiler.h>
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/*
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* In the fallback code below, we need to compute the minimum and
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* maximum values representable in a given type. These macros may also
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* be useful elsewhere, so we provide them outside the
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* COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW block.
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*
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* It would seem more obvious to do something like
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*
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* #define type_min(T) (T)(is_signed_type(T) ? (T)1 << (8*sizeof(T)-1) : 0)
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* #define type_max(T) (T)(is_signed_type(T) ? ((T)1 << (8*sizeof(T)-1)) - 1 : ~(T)0)
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*
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* Unfortunately, the middle expressions, strictly speaking, have
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* undefined behaviour, and at least some versions of gcc warn about
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* the type_max expression (but not if -fsanitize=undefined is in
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* effect; in that case, the warning is deferred to runtime...).
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*
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* The slightly excessive casting in type_min is to make sure the
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* macros also produce sensible values for the exotic type _Bool. [The
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* overflow checkers only almost work for _Bool, but that's
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* a-feature-not-a-bug, since people shouldn't be doing arithmetic on
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* _Bools. Besides, the gcc builtins don't allow _Bool* as third
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* argument.]
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*
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* Idea stolen from
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* https://mail-index.netbsd.org/tech-misc/2007/02/05/0000.html -
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* credit to Christian Biere.
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*/
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#define is_signed_type(type) (((type)(-1)) < (type)1)
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#define __type_half_max(type) ((type)1 << (8*sizeof(type) - 1 - is_signed_type(type)))
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#define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T)))
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#define type_min(T) ((T)((T)-type_max(T)-(T)1))
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#ifdef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW
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/*
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* For simplicity and code hygiene, the fallback code below insists on
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* a, b and *d having the same type (similar to the min() and max()
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* macros), whereas gcc's type-generic overflow checkers accept
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* different types. Hence we don't just make check_add_overflow an
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* alias for __builtin_add_overflow, but add type checks similar to
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* below.
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*/
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#define check_add_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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__builtin_add_overflow(__a, __b, __d); \
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})
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#define check_sub_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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__builtin_sub_overflow(__a, __b, __d); \
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})
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#define check_mul_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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__builtin_mul_overflow(__a, __b, __d); \
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})
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#else
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/* Checking for unsigned overflow is relatively easy without causing UB. */
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#define __unsigned_add_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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*__d = __a + __b; \
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*__d < __a; \
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})
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#define __unsigned_sub_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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*__d = __a - __b; \
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__a < __b; \
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})
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/*
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* If one of a or b is a compile-time constant, this avoids a division.
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*/
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#define __unsigned_mul_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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*__d = __a * __b; \
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__builtin_constant_p(__b) ? \
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__b > 0 && __a > type_max(typeof(__a)) / __b : \
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__a > 0 && __b > type_max(typeof(__b)) / __a; \
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})
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/*
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* For signed types, detecting overflow is much harder, especially if
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* we want to avoid UB. But the interface of these macros is such that
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* we must provide a result in *d, and in fact we must produce the
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* result promised by gcc's builtins, which is simply the possibly
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* wrapped-around value. Fortunately, we can just formally do the
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* operations in the widest relevant unsigned type (u64) and then
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* truncate the result - gcc is smart enough to generate the same code
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* with and without the (u64) casts.
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*/
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/*
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* Adding two signed integers can overflow only if they have the same
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* sign, and overflow has happened iff the result has the opposite
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* sign.
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*/
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#define __signed_add_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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*__d = (u64)__a + (u64)__b; \
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(((~(__a ^ __b)) & (*__d ^ __a)) \
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& type_min(typeof(__a))) != 0; \
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})
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/*
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* Subtraction is similar, except that overflow can now happen only
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* when the signs are opposite. In this case, overflow has happened if
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* the result has the opposite sign of a.
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*/
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#define __signed_sub_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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*__d = (u64)__a - (u64)__b; \
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((((__a ^ __b)) & (*__d ^ __a)) \
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& type_min(typeof(__a))) != 0; \
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})
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/*
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* Signed multiplication is rather hard. gcc always follows C99, so
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* division is truncated towards 0. This means that we can write the
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* overflow check like this:
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*
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* (a > 0 && (b > MAX/a || b < MIN/a)) ||
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* (a < -1 && (b > MIN/a || b < MAX/a) ||
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* (a == -1 && b == MIN)
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*
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* The redundant casts of -1 are to silence an annoying -Wtype-limits
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* (included in -Wextra) warning: When the type is u8 or u16, the
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* __b_c_e in check_mul_overflow obviously selects
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* __unsigned_mul_overflow, but unfortunately gcc still parses this
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* code and warns about the limited range of __b.
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*/
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#define __signed_mul_overflow(a, b, d) ({ \
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typeof(a) __a = (a); \
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typeof(b) __b = (b); \
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typeof(d) __d = (d); \
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typeof(a) __tmax = type_max(typeof(a)); \
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typeof(a) __tmin = type_min(typeof(a)); \
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(void) (&__a == &__b); \
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(void) (&__a == __d); \
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*__d = (u64)__a * (u64)__b; \
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(__b > 0 && (__a > __tmax/__b || __a < __tmin/__b)) || \
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(__b < (typeof(__b))-1 && (__a > __tmin/__b || __a < __tmax/__b)) || \
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(__b == (typeof(__b))-1 && __a == __tmin); \
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})
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#define check_add_overflow(a, b, d) \
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__builtin_choose_expr(is_signed_type(typeof(a)), \
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__signed_add_overflow(a, b, d), \
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__unsigned_add_overflow(a, b, d))
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#define check_sub_overflow(a, b, d) \
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__builtin_choose_expr(is_signed_type(typeof(a)), \
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__signed_sub_overflow(a, b, d), \
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__unsigned_sub_overflow(a, b, d))
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#define check_mul_overflow(a, b, d) \
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__builtin_choose_expr(is_signed_type(typeof(a)), \
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__signed_mul_overflow(a, b, d), \
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__unsigned_mul_overflow(a, b, d))
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#endif /* COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW */
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/**
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* array_size() - Calculate size of 2-dimensional array.
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*
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* @a: dimension one
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* @b: dimension two
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*
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* Calculates size of 2-dimensional array: @a * @b.
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*
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* Returns: number of bytes needed to represent the array or SIZE_MAX on
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* overflow.
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*/
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static inline __must_check size_t array_size(size_t a, size_t b)
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{
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size_t bytes;
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if (check_mul_overflow(a, b, &bytes))
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return SIZE_MAX;
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return bytes;
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}
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/**
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* array3_size() - Calculate size of 3-dimensional array.
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*
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* @a: dimension one
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* @b: dimension two
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* @c: dimension three
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*
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* Calculates size of 3-dimensional array: @a * @b * @c.
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*
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* Returns: number of bytes needed to represent the array or SIZE_MAX on
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* overflow.
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*/
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static inline __must_check size_t array3_size(size_t a, size_t b, size_t c)
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{
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size_t bytes;
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if (check_mul_overflow(a, b, &bytes))
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return SIZE_MAX;
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if (check_mul_overflow(bytes, c, &bytes))
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return SIZE_MAX;
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return bytes;
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}
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static inline __must_check size_t __ab_c_size(size_t n, size_t size, size_t c)
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{
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size_t bytes;
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if (check_mul_overflow(n, size, &bytes))
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return SIZE_MAX;
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if (check_add_overflow(bytes, c, &bytes))
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return SIZE_MAX;
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return bytes;
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}
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/**
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* struct_size() - Calculate size of structure with trailing array.
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* @p: Pointer to the structure.
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* @member: Name of the array member.
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* @n: Number of elements in the array.
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*
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* Calculates size of memory needed for structure @p followed by an
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* array of @n @member elements.
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*
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* Return: number of bytes needed or SIZE_MAX on overflow.
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*/
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#define struct_size(p, member, n) \
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__ab_c_size(n, \
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sizeof(*(p)->member) + __must_be_array((p)->member),\
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sizeof(*(p)))
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#endif /* __LINUX_OVERFLOW_H */
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@ -0,0 +1,20 @@
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// SPDX-License-Identifier: GPL-2.0+
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/* Copyright (C) 2018 Netronome Systems, Inc. */
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#ifndef __TOOLS_LIBC_COMPAT_H
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#define __TOOLS_LIBC_COMPAT_H
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#include <stdlib.h>
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#include <linux/overflow.h>
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#ifdef COMPAT_NEED_REALLOCARRAY
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static inline void *reallocarray(void *ptr, size_t nmemb, size_t size)
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{
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size_t bytes;
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if (unlikely(check_mul_overflow(nmemb, size, &bytes)))
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return NULL;
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return realloc(ptr, bytes);
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}
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#endif
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#endif
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@ -66,7 +66,7 @@ ifndef VERBOSE
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endif
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FEATURE_USER = .libbpf
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FEATURE_TESTS = libelf libelf-getphdrnum libelf-mmap bpf
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FEATURE_TESTS = libelf libelf-getphdrnum libelf-mmap bpf reallocarray
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FEATURE_DISPLAY = libelf bpf
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INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi -I$(srctree)/tools/perf
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@ -120,6 +120,10 @@ ifeq ($(feature-libelf-getphdrnum), 1)
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override CFLAGS += -DHAVE_ELF_GETPHDRNUM_SUPPORT
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endif
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ifeq ($(feature-reallocarray), 0)
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override CFLAGS += -DCOMPAT_NEED_REALLOCARRAY
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endif
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# Append required CFLAGS
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override CFLAGS += $(EXTRA_WARNINGS)
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override CFLAGS += -Werror -Wall
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@ -22,6 +22,7 @@
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* License along with this program; if not, see <http://www.gnu.org/licenses>
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*/
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#define _GNU_SOURCE
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdarg.h>
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@ -41,6 +42,7 @@
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/vfs.h>
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#include <tools/libc_compat.h>
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#include <libelf.h>
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#include <gelf.h>
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@ -321,7 +323,7 @@ bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
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progs = obj->programs;
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nr_progs = obj->nr_programs;
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|
||||
progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
|
||||
progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
|
||||
if (!progs) {
|
||||
/*
|
||||
* In this case the original obj->programs
|
||||
|
|
@ -822,8 +824,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
|
|||
continue;
|
||||
}
|
||||
|
||||
reloc = realloc(reloc,
|
||||
sizeof(*obj->efile.reloc) * nr_reloc);
|
||||
reloc = reallocarray(reloc, nr_reloc,
|
||||
sizeof(*obj->efile.reloc));
|
||||
if (!reloc) {
|
||||
pr_warning("realloc failed\n");
|
||||
err = -ENOMEM;
|
||||
|
|
@ -1115,7 +1117,7 @@ bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
|
|||
return -LIBBPF_ERRNO__RELOC;
|
||||
}
|
||||
new_cnt = prog->insns_cnt + text->insns_cnt;
|
||||
new_insn = realloc(prog->insns, new_cnt * sizeof(*insn));
|
||||
new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
|
||||
if (!new_insn) {
|
||||
pr_warning("oom in prog realloc\n");
|
||||
return -ENOMEM;
|
||||
|
|
|
|||
Loading…
Reference in New Issue