lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Tue, 18 Aug 2020 18:36:04 -0700
From:   Andrii Nakryiko <andriin@...com>
To:     <bpf@...r.kernel.org>, <netdev@...r.kernel.org>, <ast@...com>,
        <daniel@...earbox.net>
CC:     <andrii.nakryiko@...il.com>, <kernel-team@...com>,
        Andrii Nakryiko <andriin@...com>
Subject: [PATCH v3 bpf-next 1/4] libbpf: remove any use of reallocarray() in libbpf

Re-implement glibc's reallocarray() for libbpf internal-only use.
reallocarray(), unfortunately, is not available in all versions of glibc, so
requires extra feature detection and using reallocarray() stub from
<tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates build
of libbpf unnecessarily and is just a maintenance burden. Instead, it's
trivial to implement libbpf-specific internal version and use it throughout
libbpf.

Which is what this patch does, along with converting some realloc() uses that
should really have been reallocarray() in the first place.

Signed-off-by: Andrii Nakryiko <andriin@...com>
---
 tools/lib/bpf/Makefile          |  6 +-----
 tools/lib/bpf/btf.c             | 11 +++++------
 tools/lib/bpf/btf_dump.c        |  6 ++----
 tools/lib/bpf/libbpf.c          | 21 ++++++++++-----------
 tools/lib/bpf/libbpf_internal.h | 25 +++++++++++++++++++++++++
 tools/lib/bpf/ringbuf.c         |  5 ++---
 6 files changed, 45 insertions(+), 29 deletions(-)

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 95c946e94ca5..621ad96d06fd 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -56,7 +56,7 @@ ifndef VERBOSE
 endif
 
 FEATURE_USER = .libbpf
-FEATURE_TESTS = libelf libelf-mmap zlib bpf reallocarray
+FEATURE_TESTS = libelf libelf-mmap zlib bpf
 FEATURE_DISPLAY = libelf zlib bpf
 
 INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi
@@ -102,10 +102,6 @@ ifeq ($(feature-libelf-mmap), 1)
   override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
 endif
 
-ifeq ($(feature-reallocarray), 0)
-  override CFLAGS += -DCOMPAT_NEED_REALLOCARRAY
-endif
-
 # Append required CFLAGS
 override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum
 override CFLAGS += -Werror -Wall
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 1deedbd19c6c..1b7d85d94a07 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -61,7 +61,7 @@ static int btf_add_type(struct btf *btf, struct btf_type *t)
 		expand_by = max(btf->types_size >> 2, 16U);
 		new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by);
 
-		new_types = realloc(btf->types, sizeof(*new_types) * new_size);
+		new_types = libbpf_reallocarray(btf->types, new_size, sizeof(*new_types));
 		if (!new_types)
 			return -ENOMEM;
 
@@ -1574,7 +1574,7 @@ static int btf_dedup_hypot_map_add(struct btf_dedup *d,
 		__u32 *new_list;
 
 		d->hypot_cap += max((size_t)16, d->hypot_cap / 2);
-		new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap);
+		new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32));
 		if (!new_list)
 			return -ENOMEM;
 		d->hypot_list = new_list;
@@ -1870,8 +1870,7 @@ static int btf_dedup_strings(struct btf_dedup *d)
 			struct btf_str_ptr *new_ptrs;
 
 			strs.cap += max(strs.cnt / 2, 16U);
-			new_ptrs = realloc(strs.ptrs,
-					   sizeof(strs.ptrs[0]) * strs.cap);
+			new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0]));
 			if (!new_ptrs) {
 				err = -ENOMEM;
 				goto done;
@@ -2956,8 +2955,8 @@ static int btf_dedup_compact_types(struct btf_dedup *d)
 	d->btf->nr_types = next_type_id - 1;
 	d->btf->types_size = d->btf->nr_types;
 	d->btf->hdr->type_len = p - types_start;
-	new_types = realloc(d->btf->types,
-			    (1 + d->btf->nr_types) * sizeof(struct btf_type *));
+	new_types = libbpf_reallocarray(d->btf->types, (1 + d->btf->nr_types),
+					sizeof(struct btf_type *));
 	if (!new_types)
 		return -ENOMEM;
 	d->btf->types = new_types;
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index fe39bd774697..1ad852ad0a86 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -323,8 +323,7 @@ static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id)
 
 	if (d->emit_queue_cnt >= d->emit_queue_cap) {
 		new_cap = max(16, d->emit_queue_cap * 3 / 2);
-		new_queue = realloc(d->emit_queue,
-				    new_cap * sizeof(new_queue[0]));
+		new_queue = libbpf_reallocarray(d->emit_queue, new_cap, sizeof(new_queue[0]));
 		if (!new_queue)
 			return -ENOMEM;
 		d->emit_queue = new_queue;
@@ -1003,8 +1002,7 @@ static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id)
 
 	if (d->decl_stack_cnt >= d->decl_stack_cap) {
 		new_cap = max(16, d->decl_stack_cap * 3 / 2);
-		new_stack = realloc(d->decl_stack,
-				    new_cap * sizeof(new_stack[0]));
+		new_stack = libbpf_reallocarray(d->decl_stack, new_cap, sizeof(new_stack[0]));
 		if (!new_stack)
 			return -ENOMEM;
 		d->decl_stack = new_stack;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0276cf85d763..2653bcee73b7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -44,7 +44,6 @@
 #include <sys/vfs.h>
 #include <sys/utsname.h>
 #include <sys/resource.h>
-#include <tools/libc_compat.h>
 #include <libelf.h>
 #include <gelf.h>
 #include <zlib.h>
@@ -567,7 +566,7 @@ bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 	progs = obj->programs;
 	nr_progs = obj->nr_programs;
 
-	progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
+	progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
 	if (!progs) {
 		/*
 		 * In this case the original obj->programs
@@ -1292,7 +1291,7 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
 		return &obj->maps[obj->nr_maps++];
 
 	new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
-	new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
+	new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps));
 	if (!new_maps) {
 		pr_warn("alloc maps for object failed\n");
 		return ERR_PTR(-ENOMEM);
@@ -2721,8 +2720,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
 				continue;
 			}
 
-			sects = reallocarray(sects, nr_sects + 1,
-					     sizeof(*obj->efile.reloc_sects));
+			sects = libbpf_reallocarray(sects, nr_sects + 1,
+						    sizeof(*obj->efile.reloc_sects));
 			if (!sects) {
 				pr_warn("reloc_sects realloc failed\n");
 				return -ENOMEM;
@@ -2925,7 +2924,7 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
 			continue;
 
 		ext = obj->externs;
-		ext = reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
+		ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
 		if (!ext)
 			return -ENOMEM;
 		obj->externs = ext;
@@ -4362,9 +4361,9 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
 			pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n",
 				 local_type_id, btf_kind_str(local_t),
 				 local_name, i, targ_kind, targ_name);
-			new_ids = reallocarray(cand_ids->data,
-					       cand_ids->len + 1,
-					       sizeof(*cand_ids->data));
+			new_ids = libbpf_reallocarray(cand_ids->data,
+						      cand_ids->len + 1,
+						      sizeof(*cand_ids->data));
 			if (!new_ids) {
 				err = -ENOMEM;
 				goto err_out;
@@ -5231,7 +5230,7 @@ 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 = reallocarray(prog->insns, new_cnt, sizeof(*insn));
+		new_insn = libbpf_reallocarray(prog->insns, new_cnt, sizeof(*insn));
 		if (!new_insn) {
 			pr_warn("oom in prog realloc\n");
 			return -ENOMEM;
@@ -5473,7 +5472,7 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
 		moff /= bpf_ptr_sz;
 		if (moff >= map->init_slots_sz) {
 			new_sz = moff + 1;
-			tmp = realloc(map->init_slots, new_sz * host_ptr_sz);
+			tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz);
 			if (!tmp)
 				return -ENOMEM;
 			map->init_slots = tmp;
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index b776a7125c92..954bc2bd040c 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -9,6 +9,7 @@
 #ifndef __LIBBPF_LIBBPF_INTERNAL_H
 #define __LIBBPF_LIBBPF_INTERNAL_H
 
+#include <stdlib.h>
 #include "libbpf.h"
 
 #define BTF_INFO_ENC(kind, kind_flag, vlen) \
@@ -23,6 +24,12 @@
 #define BTF_PARAM_ENC(name, type) (name), (type)
 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
 
+#ifndef likely
+#define likely(x) __builtin_expect(!!(x), 1)
+#endif
+#ifndef unlikely
+#define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
 #ifndef min
 # define min(x, y) ((x) < (y) ? (x) : (y))
 #endif
@@ -63,6 +70,24 @@ do {				\
 #define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
 #define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
 
+/*
+ * Re-implement glibc's reallocarray() for libbpf internal-only use.
+ * reallocarray(), unfortunately, is not available in all versions of glibc,
+ * so requires extra feature detection and using reallocarray() stub from
+ * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
+ * build of libbpf unnecessarily and is just a maintenance burden. Instead,
+ * it's trivial to implement libbpf-specific internal version and use it
+ * throughout libbpf.
+ */
+static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
+{
+	size_t total;
+
+	if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
+		return NULL;
+	return realloc(ptr, total);
+}
+
 static inline bool libbpf_validate_opts(const char *opts,
 					size_t opts_sz, size_t user_sz,
 					const char *type_name)
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 4fc6c6cbb4eb..5bd234be8a14 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -16,7 +16,6 @@
 #include <asm/barrier.h>
 #include <sys/mman.h>
 #include <sys/epoll.h>
-#include <tools/libc_compat.h>
 
 #include "libbpf.h"
 #include "libbpf_internal.h"
@@ -82,12 +81,12 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 		return -EINVAL;
 	}
 
-	tmp = reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings));
+	tmp = libbpf_reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings));
 	if (!tmp)
 		return -ENOMEM;
 	rb->rings = tmp;
 
-	tmp = reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events));
+	tmp = libbpf_reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events));
 	if (!tmp)
 		return -ENOMEM;
 	rb->events = tmp;
-- 
2.24.1

Powered by blists - more mailing lists