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-rw-r--r--src/util/mymalloc.c269
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diff --git a/src/util/mymalloc.c b/src/util/mymalloc.c
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+/*++
+/* NAME
+/* mymalloc 3
+/* SUMMARY
+/* memory management wrappers
+/* SYNOPSIS
+/* #include <mymalloc.h>
+/*
+/* void *mymalloc(len)
+/* ssize_t len;
+/*
+/* void *myrealloc(ptr, len)
+/* void *ptr;
+/* ssize_t len;
+/*
+/* void myfree(ptr)
+/* void *ptr;
+/*
+/* char *mystrdup(str)
+/* const char *str;
+/*
+/* char *mystrndup(str, len)
+/* const char *str;
+/* ssize_t len;
+/*
+/* void *mymemdup(ptr, len)
+/* const void *ptr;
+/* ssize_t len;
+/* DESCRIPTION
+/* This module performs low-level memory management with error
+/* handling. A call of these functions either succeeds or it does
+/* not return at all.
+/*
+/* To save memory, zero-length strings are shared and read-only.
+/* The caller must not attempt to modify the null terminator.
+/* This code is enabled unless NO_SHARED_EMPTY_STRINGS is
+/* defined at compile time (for example, you have an sscanf()
+/* routine that pushes characters back into its input).
+/*
+/* mymalloc() allocates the requested amount of memory. The memory
+/* is not set to zero.
+/*
+/* myrealloc() resizes memory obtained from mymalloc() or myrealloc()
+/* to the requested size. The result pointer value may differ from
+/* that given via the \fIptr\fR argument.
+/*
+/* myfree() takes memory obtained from mymalloc() or myrealloc()
+/* and makes it available for other use.
+/*
+/* mystrdup() returns a dynamic-memory copy of its null-terminated
+/* argument. This routine uses mymalloc().
+/*
+/* mystrndup() returns a dynamic-memory copy of at most \fIlen\fR
+/* leading characters of its null-terminated
+/* argument. The result is null-terminated. This routine uses mymalloc().
+/*
+/* mymemdup() makes a copy of the memory pointed to by \fIptr\fR
+/* with length \fIlen\fR. The result is NOT null-terminated.
+/* This routine uses mymalloc().
+/* SEE ALSO
+/* msg(3) diagnostics interface
+/* DIAGNOSTICS
+/* Problems are reported via the msg(3) diagnostics routines:
+/* the requested amount of memory is not available; improper use
+/* is detected; other fatal errors.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*
+/* Wietse Venema
+/* Google, Inc.
+/* 111 8th Avenue
+/* New York, NY 10011, USA
+/*--*/
+
+/* System libraries. */
+
+#include "sys_defs.h"
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+
+/* Application-specific. */
+
+#include "msg.h"
+#include "mymalloc.h"
+
+ /*
+ * Structure of an annotated memory block. In order to detect spurious
+ * free() calls we prepend a signature to memory given to the application.
+ * In order to detect access to free()d blocks, overwrite each block as soon
+ * as it is passed to myfree(). With the code below, the user data has
+ * integer alignment or better.
+ */
+typedef struct MBLOCK {
+ int signature; /* set when block is active */
+ ssize_t length; /* user requested length */
+ union {
+ ALIGN_TYPE align;
+ char payload[1]; /* actually a bunch of bytes */
+ } u;
+} MBLOCK;
+
+#define SIGNATURE 0xdead
+#define FILLER 0xff
+
+#define CHECK_IN_PTR(ptr, real_ptr, len, fname) { \
+ if (ptr == 0) \
+ msg_panic("%s: null pointer input", fname); \
+ real_ptr = (MBLOCK *) (ptr - offsetof(MBLOCK, u.payload[0])); \
+ if (real_ptr->signature != SIGNATURE) \
+ msg_panic("%s: corrupt or unallocated memory block", fname); \
+ real_ptr->signature = 0; \
+ if ((len = real_ptr->length) < 1) \
+ msg_panic("%s: corrupt memory block length", fname); \
+}
+
+#define CHECK_OUT_PTR(ptr, real_ptr, len) { \
+ real_ptr->signature = SIGNATURE; \
+ real_ptr->length = len; \
+ ptr = real_ptr->u.payload; \
+}
+
+#define SPACE_FOR(len) (offsetof(MBLOCK, u.payload[0]) + len)
+
+ /*
+ * Optimization for short strings. We share one copy with multiple callers.
+ * This differs from normal heap memory in two ways, because the memory is
+ * shared:
+ *
+ * - It must be read-only to avoid horrible bugs. This is OK because there is
+ * no legitimate reason to modify the null terminator.
+ *
+ * - myfree() cannot overwrite the memory with a filler pattern like it can do
+ * with heap memory. Therefore, some dangling pointer bugs will be masked.
+ */
+#ifndef NO_SHARED_EMPTY_STRINGS
+static const char empty_string[] = "";
+
+#endif
+
+/* mymalloc - allocate memory or bust */
+
+void *mymalloc(ssize_t len)
+{
+ void *ptr;
+ MBLOCK *real_ptr;
+
+ /*
+ * Note: for safety reasons the request length is a signed type. This
+ * allows us to catch integer overflow problems that weren't already
+ * caught up-stream.
+ */
+ if (len < 1)
+ msg_panic("mymalloc: requested length %ld", (long) len);
+#ifdef MYMALLOC_FUZZ
+ len += MYMALLOC_FUZZ;
+#endif
+ if ((real_ptr = (MBLOCK *) malloc(SPACE_FOR(len))) == 0)
+ msg_fatal("mymalloc: insufficient memory for %ld bytes: %m",
+ (long) len);
+ CHECK_OUT_PTR(ptr, real_ptr, len);
+ memset(ptr, FILLER, len);
+ return (ptr);
+}
+
+/* myrealloc - reallocate memory or bust */
+
+void *myrealloc(void *ptr, ssize_t len)
+{
+ MBLOCK *real_ptr;
+ ssize_t old_len;
+
+#ifndef NO_SHARED_EMPTY_STRINGS
+ if (ptr == empty_string)
+ return (mymalloc(len));
+#endif
+
+ /*
+ * Note: for safety reasons the request length is a signed type. This
+ * allows us to catch integer overflow problems that weren't already
+ * caught up-stream.
+ */
+ if (len < 1)
+ msg_panic("myrealloc: requested length %ld", (long) len);
+#ifdef MYMALLOC_FUZZ
+ len += MYMALLOC_FUZZ;
+#endif
+ CHECK_IN_PTR(ptr, real_ptr, old_len, "myrealloc");
+ if ((real_ptr = (MBLOCK *) realloc((void *) real_ptr, SPACE_FOR(len))) == 0)
+ msg_fatal("myrealloc: insufficient memory for %ld bytes: %m",
+ (long) len);
+ CHECK_OUT_PTR(ptr, real_ptr, len);
+ if (len > old_len)
+ memset(ptr + old_len, FILLER, len - old_len);
+ return (ptr);
+}
+
+/* myfree - release memory */
+
+void myfree(void *ptr)
+{
+ MBLOCK *real_ptr;
+ ssize_t len;
+
+#ifndef NO_SHARED_EMPTY_STRINGS
+ if (ptr != empty_string) {
+#endif
+ CHECK_IN_PTR(ptr, real_ptr, len, "myfree");
+ memset((void *) real_ptr, FILLER, SPACE_FOR(len));
+ free((void *) real_ptr);
+#ifndef NO_SHARED_EMPTY_STRINGS
+ }
+#endif
+}
+
+/* mystrdup - save string to heap */
+
+char *mystrdup(const char *str)
+{
+ size_t len;
+
+ if (str == 0)
+ msg_panic("mystrdup: null pointer argument");
+#ifndef NO_SHARED_EMPTY_STRINGS
+ if (*str == 0)
+ return ((char *) empty_string);
+#endif
+ if ((len = strlen(str) + 1) > SSIZE_T_MAX)
+ msg_panic("mystrdup: string length >= SSIZE_T_MAX");
+ return (memcpy(mymalloc(len), str, len));
+}
+
+/* mystrndup - save substring to heap */
+
+char *mystrndup(const char *str, ssize_t len)
+{
+ char *result;
+ char *cp;
+
+ if (str == 0)
+ msg_panic("mystrndup: null pointer argument");
+ if (len < 0)
+ msg_panic("mystrndup: requested length %ld", (long) len);
+#ifndef NO_SHARED_EMPTY_STRINGS
+ if (*str == 0)
+ return ((char *) empty_string);
+#endif
+ if ((cp = memchr(str, 0, len)) != 0)
+ len = cp - str;
+ result = memcpy(mymalloc(len + 1), str, len);
+ result[len] = 0;
+ return (result);
+}
+
+/* mymemdup - copy memory */
+
+void *mymemdup(const void *ptr, ssize_t len)
+{
+ if (ptr == 0)
+ msg_panic("mymemdup: null pointer argument");
+ return (memcpy(mymalloc(len), ptr, len));
+}
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