[ Charset UTF-8 unsupported, converting... ]
> Author: kp
> Date: Sun Jan 7 13:21:01 2018
> New Revision: 327674
> URL: https://svnweb.freebsd.org/changeset/base/327674
>
> Log:
> Introduce mallocarray() in the kernel
>
> Similar to calloc() the mallocarray() function checks for integer
> overflows before allocating memory.
> It does not zero memory, unless the M_ZERO flag is set.
>
> Reviewed by: pfg, vangyzen (previous version), imp (previous version)
> Obtained from: OpenBSD
> Differential Revision: https://reviews.freebsd.org/D13766
>
> Modified:
> head/share/man/man9/malloc.9
> head/sys/kern/kern_malloc.c
> head/sys/sys/malloc.h
>
> Modified: head/share/man/man9/malloc.9
> ==============================================================================
> --- head/share/man/man9/malloc.9 Sun Jan 7 10:29:15 2018
> (r327673)
> +++ head/share/man/man9/malloc.9 Sun Jan 7 13:21:01 2018
> (r327674)
> @@ -45,6 +45,8 @@
> .In sys/malloc.h
> .Ft void *
> .Fn malloc "unsigned long size" "struct malloc_type *type" "int flags"
> +.Ft void *
> +.Fn mallocarray "size_t nmemb" "size_t size" "struct malloc_type *type" "int
> flags"
> .Ft void
> .Fn free "void *addr" "struct malloc_type *type"
> .Ft void *
> @@ -64,6 +66,14 @@ object whose size is specified by
> .Fa size .
> .Pp
> The
> +.Fn mallocarray
> +function allocates uninitialized memory in kernel address space for an
> +array of
> +.Fa nmemb
> +entries whose size is specified by
> +.Fa size .
> +.Pp
> +The
> .Fn free
> function releases memory at address
> .Fa addr
> @@ -152,6 +162,15 @@ functions cannot return
> if
> .Dv M_WAITOK
> is specified.
> +The
> +.Fn mallocarray
> +function can return
> +.Dv NULL
> +if the multiplication of
> +.Fa nmemb
> +and
> +.Fa size
> +would cause an integer overflow.
> .It Dv M_USE_RESERVE
> Indicates that the system can use its reserve of memory to satisfy the
> request.
>
> Modified: head/sys/kern/kern_malloc.c
> ==============================================================================
> --- head/sys/kern/kern_malloc.c Sun Jan 7 10:29:15 2018
> (r327673)
> +++ head/sys/kern/kern_malloc.c Sun Jan 7 13:21:01 2018
> (r327674)
> @@ -4,6 +4,7 @@
> * Copyright (c) 1987, 1991, 1993
> * The Regents of the University of California.
> * Copyright (c) 2005-2009 Robert N. M. Watson
> + * Copyright (c) 2008 Otto Moerbeek <o...@drijf.net> (mallocarray)
Is this code really over a decade old???? or is this a typo?
> * All rights reserved.
> *
> * Redistribution and use in source and binary forms, with or without
> @@ -532,6 +533,22 @@ malloc(unsigned long size, struct malloc_type *mtp, in
> va = redzone_setup(va, osize);
> #endif
> return ((void *) va);
> +}
> +
> +/*
> + * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
> + * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
> + */
> +#define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 8 / 2))
> +void *
> +mallocarray(size_t nmemb, size_t size, struct malloc_type *type, int flags)
> +{
> +
> + if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
> + nmemb > 0 && SIZE_MAX / nmemb < size)
> + return (NULL);
> +
> + return (malloc(size * nmemb, type, flags));
> }
>
> /*
>
> Modified: head/sys/sys/malloc.h
> ==============================================================================
> --- head/sys/sys/malloc.h Sun Jan 7 10:29:15 2018 (r327673)
> +++ head/sys/sys/malloc.h Sun Jan 7 13:21:01 2018 (r327674)
> @@ -177,6 +177,9 @@ void *contigmalloc(unsigned long size, struct
> malloc_t
> void free(void *addr, struct malloc_type *type);
> void *malloc(unsigned long size, struct malloc_type *type, int flags)
> __malloc_like __result_use_check __alloc_size(1);
> +void *mallocarray(size_t nmemb, size_t size, struct malloc_type *type,
> + int flags) __malloc_like __result_use_check
> + __alloc_size(1) __alloc_size(2);
> void malloc_init(void *);
> int malloc_last_fail(void);
> void malloc_type_allocated(struct malloc_type *type, unsigned long size);
>
>
--
Rod Grimes rgri...@freebsd.org
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
