diff options
Diffstat (limited to 'malloc')
| -rw-r--r-- | malloc/Makefile | 4 | ||||
| -rw-r--r-- | malloc/Versions | 4 | ||||
| -rw-r--r-- | malloc/malloc-internal.h | 19 | ||||
| -rw-r--r-- | malloc/malloc.h | 8 | ||||
| -rw-r--r-- | malloc/reallocarray.c | 37 | ||||
| -rw-r--r-- | malloc/tst-reallocarray.c | 118 |
6 files changed, 188 insertions, 2 deletions
diff --git a/malloc/Makefile b/malloc/Makefile index d0f23f7bf3..b7d4c63920 100644 --- a/malloc/Makefile +++ b/malloc/Makefile @@ -26,7 +26,7 @@ dist-headers := malloc.h headers := $(dist-headers) obstack.h mcheck.h tests := mallocbug tst-malloc tst-valloc tst-calloc tst-obstack \ tst-mcheck tst-mallocfork tst-trim1 \ - tst-malloc-usable tst-realloc tst-posix_memalign \ + tst-malloc-usable tst-realloc tst-reallocarray tst-posix_memalign \ tst-pvalloc tst-memalign tst-mallopt \ tst-malloc-backtrace tst-malloc-thread-exit \ tst-malloc-thread-fail tst-malloc-fork-deadlock \ @@ -49,7 +49,7 @@ endif tests += $(tests-static) test-srcs = tst-mtrace -routines = malloc morecore mcheck mtrace obstack \ +routines = malloc morecore mcheck mtrace obstack reallocarray \ scratch_buffer_grow scratch_buffer_grow_preserve \ scratch_buffer_set_array_size diff --git a/malloc/Versions b/malloc/Versions index e34ab177be..23aafb5ccc 100644 --- a/malloc/Versions +++ b/malloc/Versions @@ -62,6 +62,7 @@ libc { aligned_alloc; } GLIBC_2.26 { + reallocarray; } GLIBC_PRIVATE { # Internal startup hook for libpthread. @@ -74,5 +75,8 @@ libc { __libc_scratch_buffer_grow; __libc_scratch_buffer_grow_preserve; __libc_scratch_buffer_set_array_size; + + # Internal name for reallocarray + __libc_reallocarray; } } diff --git a/malloc/malloc-internal.h b/malloc/malloc-internal.h index de6103d7e1..dbd801a58e 100644 --- a/malloc/malloc-internal.h +++ b/malloc/malloc-internal.h @@ -81,5 +81,24 @@ void __malloc_fork_unlock_parent (void) internal_function attribute_hidden; /* Called in the child process after a fork. */ void __malloc_fork_unlock_child (void) internal_function attribute_hidden; +/* Set *RESULT to LEFT * RIGHT. Return true if the multiplication + overflowed. */ +static inline bool +check_mul_overflow_size_t (size_t left, size_t right, size_t *result) +{ +#if __GNUC__ >= 5 + return __builtin_mul_overflow (left, right, result); +#else + /* size_t is unsigned so the behavior on overflow is defined. */ + *result = left * right; + size_t half_size_t = ((size_t) 1) << (8 * sizeof (size_t) / 2); + if (__glibc_unlikely ((left | right) >= half_size_t)) + { + if (__glibc_unlikely (right != 0 && *result / right != left)) + return true; + } + return false; +#endif +} #endif /* _MALLOC_INTERNAL_H */ diff --git a/malloc/malloc.h b/malloc/malloc.h index 274c0958e4..339ab64c7d 100644 --- a/malloc/malloc.h +++ b/malloc/malloc.h @@ -49,6 +49,14 @@ __THROW __attribute_malloc__ __wur; extern void *realloc (void *__ptr, size_t __size) __THROW __attribute_warn_unused_result__; +/* Re-allocate the previously allocated block in PTR, making the new + block large enough for NMEMB elements of SIZE bytes each. */ +/* __attribute_malloc__ is not used, because if reallocarray returns + the same pointer that was passed to it, aliasing needs to be allowed + between objects pointed by the old and new pointers. */ +extern void *reallocarray (void *__ptr, size_t __nmemb, size_t __size) +__THROW __attribute_warn_unused_result__; + /* Free a block allocated by `malloc', `realloc' or `calloc'. */ extern void free (void *__ptr) __THROW; diff --git a/malloc/reallocarray.c b/malloc/reallocarray.c new file mode 100644 index 0000000000..07562c30c9 --- /dev/null +++ b/malloc/reallocarray.c @@ -0,0 +1,37 @@ +/* Change the size of an allocated block. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, see <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <malloc.h> +#include <malloc/malloc-internal.h> + +void * +__libc_reallocarray (void *optr, size_t nmemb, size_t elem_size) +{ + size_t bytes; + if (check_mul_overflow_size_t (nmemb, elem_size, &bytes)) + { + __set_errno (ENOMEM); + return 0; + } + else + return realloc (optr, bytes); +} +libc_hidden_def (__libc_reallocarray) + +weak_alias (__libc_reallocarray, reallocarray) diff --git a/malloc/tst-reallocarray.c b/malloc/tst-reallocarray.c new file mode 100644 index 0000000000..f1cbf7fe0a --- /dev/null +++ b/malloc/tst-reallocarray.c @@ -0,0 +1,118 @@ +/* Test for reallocarray. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <malloc.h> +#include <string.h> +#include <support/check.h> + +static int +do_test (void) +{ + void *ptr = NULL; + void *ptr2 = NULL; + unsigned char *c; + size_t i; + int ok; + const size_t max = ~(size_t)0; + size_t a, b; + + /* Test overflow detection. */ + errno = 0; + ptr = reallocarray (NULL, max, 2); + TEST_VERIFY (!ptr); + TEST_VERIFY (errno == ENOMEM); + + errno = 0; + ptr = reallocarray (NULL, 2, max); + TEST_VERIFY (!ptr); + TEST_VERIFY (errno == ENOMEM); + + a = 65537; + b = max/65537 + 1; + errno = 0; + ptr = reallocarray (NULL, a, b); + TEST_VERIFY (!ptr); + TEST_VERIFY (errno == ENOMEM); + + errno = 0; + ptr = reallocarray (NULL, b, a); + TEST_VERIFY (!ptr); + TEST_VERIFY (errno == ENOMEM); + + /* Test realloc-like behavior. */ + /* Allocate memory like malloc. */ + ptr = reallocarray (NULL, 10, 2); + TEST_VERIFY_EXIT (ptr); + TEST_VERIFY_EXIT (malloc_usable_size (ptr) >= 10*2); + + memset (ptr, 0xAF, 10*2); + + /* Enlarge buffer. */ + ptr2 = reallocarray (ptr, 20, 2); + TEST_VERIFY (ptr2); + if (ptr2) + ptr = ptr2; + TEST_VERIFY (malloc_usable_size (ptr) >= 20*2); + + c = ptr; + ok = 1; + for (i = 0; i < 10*2; ++i) + { + if (c[i] != 0xAF) + ok = 0; + } + TEST_VERIFY (ok); + + /* Decrease buffer size. */ + ptr2 = reallocarray (ptr, 5, 3); + TEST_VERIFY (ptr2); + if (ptr2) + ptr = ptr2; + TEST_VERIFY_EXIT (malloc_usable_size (ptr) >= 5*3); + + c = ptr; + ok = 1; + for (i = 0; i < 5*3; ++i) + { + if (c[i] != 0xAF) + ok = 0; + } + TEST_VERIFY (ok); + + /* Overflow should leave buffer untouched. */ + errno = 0; + ptr2 = reallocarray (ptr, 2, ~(size_t)0); + TEST_VERIFY (!ptr2); + TEST_VERIFY (errno == ENOMEM); + + c = ptr; + ok = 1; + for (i = 0; i < 5*3; ++i) + { + if (c[i] != 0xAF) + ok = 0; + } + TEST_VERIFY (ok); + + free (ptr); + + return 0; +} + +#include <support/test-driver.c> |