Mercurial > gnulib
changeset 18614:fc83941f45c2
xalloc: x2nrealloc check for ptrdiff_t overflow
* lib/xalloc.h (x2nrealloc): Check for ptrdiff_t overflow, too.
* modules/xalloc, modules/xvasprintf (Depends-on): Add stdint.
| author | Paul Eggert <eggert@cs.ucla.edu> |
|---|---|
| date | Thu, 29 Dec 2016 01:16:51 -0800 |
| parents | 84a02e55bf0c |
| children | 947216b8fda6 |
| files | ChangeLog lib/xalloc.h modules/xalloc modules/xvasprintf |
| diffstat | 4 files changed, 14 insertions(+), 4 deletions(-) [+] |
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--- a/ChangeLog Sat Dec 24 18:21:59 2016 +0100 +++ b/ChangeLog Thu Dec 29 01:16:51 2016 -0800 @@ -1,3 +1,9 @@ +2016-12-29 Paul Eggert <eggert@cs.ucla.edu> + + xalloc: x2nrealloc check for ptrdiff_t overflow + * lib/xalloc.h (x2nrealloc): Check for ptrdiff_t overflow, too. + * modules/xalloc, modules/xvasprintf (Depends-on): Add stdint. + 2016-12-24 Bruno Haible <bruno@clisp.org> lock test: Fix performance problem on multi-core machines.
--- a/lib/xalloc.h Sat Dec 24 18:21:59 2016 +0100 +++ b/lib/xalloc.h Thu Dec 29 01:16:51 2016 -0800 @@ -19,6 +19,7 @@ #define XALLOC_H_ #include <stddef.h> +#include <stdint.h> #include "xalloc-oversized.h" @@ -197,10 +198,11 @@ else { /* Set N = floor (1.5 * N) + 1 so that progress is made even if N == 0. - Check for overflow, so that N * S stays in size_t range. - The check may be slightly conservative, but an exact check isn't - worth the trouble. */ - if ((size_t) -1 / 3 * 2 / s <= n) + Check for overflow, so that N * S stays in both ptrdiff_t and + size_t range. The check may be slightly conservative, but an + exact check isn't worth the trouble. */ + if ((PTRDIFF_MAX < SIZE_MAX ? PTRDIFF_MAX : SIZE_MAX) / 3 * 2 / s + <= n) xalloc_die (); n += n / 2 + 1; }