proc/alloc.*: Use size_t, not unsigned int.

Otherwise this can truncate sizes on 64-bit platforms, and is one of the
reasons the integer overflows in file2strvec() are exploitable at all.
Also: catch potential integer overflow in xstrdup() (should never
happen, but better safe than sorry), and use memcpy() instead of
strcpy() (faster).

Warnings:

- in glibc, realloc(ptr, 0) is equivalent to free(ptr), but not here,
  because of the ++size;

- here, xstrdup() can return NULL (if str is NULL), which goes against
  the idea of the xalloc wrappers.

We were tempted to call exit() or xerrx() in those cases, but decided
against it, because it might break things in unexpected places; TODO?

diff --git a/proc/alloc.c b/proc/alloc.c
index 3cdb60fc9d987102d428640b1abca625d0f7f190..0efd5a76ea939f20a981cd729f384f5bf34485a9 100644 (file)
--- a/proc/alloc.c
+++ b/proc/alloc.c
@@ -37,14 +37,14 @@ static void xdefault_error(const char *restrict fmts, ...) {
 message_fn xalloc_err_handler = xdefault_error;
 
 
-void *xcalloc(unsigned int size) {
+void *xcalloc(size_t size) {
     void * p;
 
     if (size == 0)
         ++size;
     p = calloc(1, size);
     if (!p) {
-        xalloc_err_handler("%s failed to allocate %u bytes of memory", __func__, size);
+        xalloc_err_handler("%s failed to allocate %zu bytes of memory", __func__, size);
         exit(EXIT_FAILURE);
     }
     return p;
@@ -57,20 +57,20 @@ void *xmalloc(size_t size) {
         ++size;
     p = malloc(size);
     if (!p) {
-       xalloc_err_handler("%s failed to allocate %zu bytes of memory", __func__, size);
+        xalloc_err_handler("%s failed to allocate %zu bytes of memory", __func__, size);
         exit(EXIT_FAILURE);
     }
     return(p);
 }
 
-void *xrealloc(void *oldp, unsigned int size) {
+void *xrealloc(void *oldp, size_t size) {
     void *p;
 
     if (size == 0)
         ++size;
     p = realloc(oldp, size);
     if (!p) {
-        xalloc_err_handler("%s failed to allocate %u bytes of memory", __func__, size);
+        xalloc_err_handler("%s failed to allocate %zu bytes of memory", __func__, size);
         exit(EXIT_FAILURE);
     }
     return(p);
@@ -80,13 +80,17 @@ char *xstrdup(const char *str) {
     char *p = NULL;
 
     if (str) {
-        unsigned int size = strlen(str) + 1;
+        size_t size = strlen(str) + 1;
+        if (size < 1) {
+            xalloc_err_handler("%s refused to allocate %zu bytes of memory", __func__, size);
+            exit(EXIT_FAILURE);
+        }
         p = malloc(size);
         if (!p) {
-            xalloc_err_handler("%s failed to allocate %u bytes of memory", __func__, size);
+            xalloc_err_handler("%s failed to allocate %zu bytes of memory", __func__, size);
             exit(EXIT_FAILURE);
         }
-        strcpy(p, str);
+        memcpy(p, str, size);
     }
     return(p);
 }

diff --git a/proc/alloc.h b/proc/alloc.h
index eedbb2ba9fd22a1b38accc8179c13e5529705704..12abb848ed6b4a72679ae51545d34296483f37f2 100644 (file)
--- a/proc/alloc.h
+++ b/proc/alloc.h
@@ -10,9 +10,9 @@ typedef void (*message_fn)(const char *__restrict, ...) __attribute__((format(pr
  /* change xalloc_err_handler to override the default fprintf(stderr... */
 extern message_fn xalloc_err_handler;
 
-extern void *xcalloc(unsigned int size) MALLOC;
+extern void *xcalloc(size_t size) MALLOC;
 extern void *xmalloc(size_t size) MALLOC;
-extern void *xrealloc(void *oldp, unsigned int size) MALLOC;
+extern void *xrealloc(void *oldp, size_t size) MALLOC;
 extern char *xstrdup(const char *str) MALLOC;
 
 EXTERN_C_END