From: Jim Meyering Date: Thu, 2 Jul 2009 13:39:08 +0000 (+0200) Subject: use safe_malloc and safe_calloc in generated code X-Git-Tag: 1.0.56~8^2~25 X-Git-Url: http://git.annexia.org/?a=commitdiff_plain;h=447dae7df43e8a98da59d94f1aef9895e087aa13;p=libguestfs.git use safe_malloc and safe_calloc in generated code * src/generator.ml (safe_malloc): Define to guestfs_safe_malloc. (safe_calloc): Define to guestfs_safe_calloc. [most generated code]: Fail immediately upon failure of otherwise- unchecked malloc and calloc calls. * src/guestfs.c: Include . (xalloc_oversized): Define. * src/guestfs.h (guestfs_safe_calloc): Declare. --- diff --git a/src/generator.ml b/src/generator.ml index 4b7efa0..c65e717 100755 --- a/src/generator.ml +++ b/src/generator.ml @@ -121,7 +121,7 @@ type flags = | NotInDocs (* do not add this function to documentation *) let protocol_limit_warning = - "Because of the message protocol, there is a transfer limit + "Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. To transfer large files you should use FTP." @@ -6396,7 +6396,7 @@ Sys::Guestfs - Perl bindings for libguestfs =head1 SYNOPSIS use Sys::Guestfs; - + my $h = Sys::Guestfs->new (); $h->add_drive ('guest.img'); $h->launch (); @@ -8144,6 +8144,8 @@ and generate_bindtests () = #include \"guestfs_protocol.h\" #define error guestfs_error +#define safe_calloc guestfs_safe_calloc +#define safe_malloc guestfs_safe_malloc static void print_strings (char * const* const argv) @@ -8219,70 +8221,70 @@ print_strings (char * const* const argv) pr " char **strs;\n"; pr " int n, i;\n"; pr " sscanf (val, \"%%d\", &n);\n"; - pr " strs = malloc ((n+1) * sizeof (char *));\n"; + pr " strs = safe_malloc (g, (n+1) * sizeof (char *));\n"; pr " for (i = 0; i < n; ++i) {\n"; - pr " strs[i] = malloc (16);\n"; + pr " strs[i] = safe_malloc (g, 16);\n"; pr " snprintf (strs[i], 16, \"%%d\", i);\n"; pr " }\n"; pr " strs[n] = NULL;\n"; pr " return strs;\n" | RIntBool _ -> pr " struct guestfs_int_bool *r;\n"; - pr " r = malloc (sizeof *r);\n"; + pr " r = safe_malloc (g, sizeof *r);\n"; pr " sscanf (val, \"%%\" SCNi32, &r->i);\n"; pr " r->b = 0;\n"; pr " return r;\n" | RPVList _ -> pr " struct guestfs_lvm_pv_list *r;\n"; pr " int i;\n"; - pr " r = malloc (sizeof *r);\n"; + pr " r = safe_malloc (g, sizeof *r);\n"; pr " sscanf (val, \"%%d\", &r->len);\n"; - pr " r->val = calloc (r->len, sizeof *r->val);\n"; + pr " r->val = safe_calloc (g, r->len, sizeof *r->val);\n"; pr " for (i = 0; i < r->len; ++i) {\n"; - pr " r->val[i].pv_name = malloc (16);\n"; + pr " r->val[i].pv_name = safe_malloc (g, 16);\n"; pr " snprintf (r->val[i].pv_name, 16, \"%%d\", i);\n"; pr " }\n"; pr " return r;\n" | RVGList _ -> pr " struct guestfs_lvm_vg_list *r;\n"; pr " int i;\n"; - pr " r = malloc (sizeof *r);\n"; + pr " r = safe_malloc (g, sizeof *r);\n"; pr " sscanf (val, \"%%d\", &r->len);\n"; - pr " r->val = calloc (r->len, sizeof *r->val);\n"; + pr " r->val = safe_calloc (g, r->len, sizeof *r->val);\n"; pr " for (i = 0; i < r->len; ++i) {\n"; - pr " r->val[i].vg_name = malloc (16);\n"; + pr " r->val[i].vg_name = safe_malloc (g, 16);\n"; pr " snprintf (r->val[i].vg_name, 16, \"%%d\", i);\n"; pr " }\n"; pr " return r;\n" | RLVList _ -> pr " struct guestfs_lvm_lv_list *r;\n"; pr " int i;\n"; - pr " r = malloc (sizeof *r);\n"; + pr " r = safe_malloc (g, sizeof *r);\n"; pr " sscanf (val, \"%%d\", &r->len);\n"; - pr " r->val = calloc (r->len, sizeof *r->val);\n"; + pr " r->val = safe_calloc (g, r->len, sizeof *r->val);\n"; pr " for (i = 0; i < r->len; ++i) {\n"; - pr " r->val[i].lv_name = malloc (16);\n"; + pr " r->val[i].lv_name = safe_malloc (g, 16);\n"; pr " snprintf (r->val[i].lv_name, 16, \"%%d\", i);\n"; pr " }\n"; pr " return r;\n" | RStat _ -> pr " struct guestfs_stat *r;\n"; - pr " r = calloc (1, sizeof (*r));\n"; + pr " r = safe_calloc (g, 1, sizeof (*r));\n"; pr " sscanf (val, \"%%\" SCNi64, &r->dev);\n"; pr " return r;\n" | RStatVFS _ -> pr " struct guestfs_statvfs *r;\n"; - pr " r = calloc (1, sizeof (*r));\n"; + pr " r = safe_calloc (g, 1, sizeof (*r));\n"; pr " sscanf (val, \"%%\" SCNi64, &r->bsize);\n"; pr " return r;\n" | RHashtable _ -> pr " char **strs;\n"; pr " int n, i;\n"; pr " sscanf (val, \"%%d\", &n);\n"; - pr " strs = malloc ((n*2+1) * sizeof (*strs));\n"; + pr " strs = safe_malloc (g, (n*2+1) * sizeof (*strs));\n"; pr " for (i = 0; i < n; ++i) {\n"; - pr " strs[i*2] = malloc (16);\n"; - pr " strs[i*2+1] = malloc (16);\n"; + pr " strs[i*2] = safe_malloc (g, 16);\n"; + pr " strs[i*2+1] = safe_malloc (g, 16);\n"; pr " snprintf (strs[i*2], 16, \"%%d\", i);\n"; pr " snprintf (strs[i*2+1], 16, \"%%d\", i);\n"; pr " }\n"; @@ -8291,9 +8293,9 @@ print_strings (char * const* const argv) | RDirentList _ -> pr " struct guestfs_dirent_list *r;\n"; pr " int i;\n"; - pr " r = malloc (sizeof *r);\n"; + pr " r = safe_malloc (g, sizeof *r);\n"; pr " sscanf (val, \"%%d\", &r->len);\n"; - pr " r->val = calloc (r->len, sizeof *r->val);\n"; + pr " r->val = safe_calloc (g, r->len, sizeof *r->val);\n"; pr " for (i = 0; i < r->len; ++i)\n"; pr " r->val[i].ino = i;\n"; pr " return r;\n" diff --git a/src/guestfs.c b/src/guestfs.c index c3bce0b..350d848 100644 --- a/src/guestfs.c +++ b/src/guestfs.c @@ -1,5 +1,5 @@ /* libguestfs - * Copyright (C) 2009 Red Hat Inc. + * Copyright (C) 2009 Red Hat Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -453,6 +454,42 @@ guestfs_safe_malloc (guestfs_h *g, size_t nbytes) return ptr; } +/* Return 1 if an array of N objects, each of size S, cannot exist due + to size arithmetic overflow. S must be positive and N must be + nonnegative. This is a macro, not an inline function, so that it + works correctly even when SIZE_MAX < N. + + By gnulib convention, SIZE_MAX represents overflow in size + calculations, so the conservative dividend to use here is + SIZE_MAX - 1, since SIZE_MAX might represent an overflowed value. + However, malloc (SIZE_MAX) fails on all known hosts where + sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for + exactly-SIZE_MAX allocations on such hosts; this avoids a test and + branch when S is known to be 1. */ +# define xalloc_oversized(n, s) \ + ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n)) + +/* Technically we should add an autoconf test for this, testing for the desired + functionality, like what's done in gnulib, but for now, this is fine. */ +#define HAVE_GNU_CALLOC (__GLIBC__ >= 2) + +/* Allocate zeroed memory for N elements of S bytes, with error + checking. S must be nonzero. */ +void * +guestfs_safe_calloc (guestfs_h *g, size_t n, size_t s) +{ + /* From gnulib's calloc function in xmalloc.c. */ + void *p; + /* Test for overflow, since some calloc implementations don't have + proper overflow checks. But omit overflow and size-zero tests if + HAVE_GNU_CALLOC, since GNU calloc catches overflow and never + returns NULL if successful. */ + if ((! HAVE_GNU_CALLOC && xalloc_oversized (n, s)) + || (! (p = calloc (n, s)) && (HAVE_GNU_CALLOC || n != 0))) + g->abort_cb (); + return p; +} + void * guestfs_safe_realloc (guestfs_h *g, void *ptr, int nbytes) { diff --git a/src/guestfs.h b/src/guestfs.h index 201d60c..264986f 100644 --- a/src/guestfs.h +++ b/src/guestfs.h @@ -1,5 +1,5 @@ /* libguestfs - * Copyright (C) 2009 Red Hat Inc. + * Copyright (C) 2009 Red Hat Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -77,6 +77,7 @@ extern void guestfs_error (guestfs_h *g, const char *fs, ...) extern void guestfs_perrorf (guestfs_h *g, const char *fs, ...) __attribute__((format (printf,2,3))); extern void *guestfs_safe_malloc (guestfs_h *g, size_t nbytes); +extern void *guestfs_safe_calloc (guestfs_h *g, size_t n, size_t s); extern void *guestfs_safe_realloc (guestfs_h *g, void *ptr, int nbytes); extern char *guestfs_safe_strdup (guestfs_h *g, const char *str); extern void *guestfs_safe_memdup (guestfs_h *g, void *ptr, size_t size);