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Date: Mon, 28 Nov 2011 18:55:43 +0100
From: Stefan Weil <sw@weilnetz.de>
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Subject: Re: [Qemu-devel] [PATCH v2] bsd_user: Fix potential null pointer
 dereference
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To: Blue Swirl <blauwirbel@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Anthony Liguori <aliguori@us.ibm.com>, qemu-devel@nongnu.org

Am 21.11.2011 21:06, schrieb Stefan Weil:
> This bug was spotted by cppcheck.
>
> Using g_try_malloc0 (as does the linux-user code) fixes this.
>
> v2:
> Use g_free in bsdload.c, too. Thanks to Peter Maydell for this hint.
>
> Signed-off-by: Stefan Weil<sw@weilnetz.de>
> ---
>   bsd-user/bsdload.c |    2 +-
>   bsd-user/elfload.c |    5 ++---
>   2 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/bsd-user/bsdload.c b/bsd-user/bsdload.c
> index 6d9bb6f..2abc713 100644
> --- a/bsd-user/bsdload.c
> +++ b/bsd-user/bsdload.c
> @@ -196,7 +196,7 @@ int loader_exec(const char * filename, char ** argv, char ** envp,
>
>       /* Something went wrong, return the inode and free the argument pages*/
>       for (i=0 ; i<MAX_ARG_PAGES ; i++) {
> -        free(bprm.page[i]);
> +        g_free(bprm.page[i]);
>       }
>       return(retval);
>   }
> diff --git a/bsd-user/elfload.c b/bsd-user/elfload.c
> index 1ef1f97..1288884 100644
> --- a/bsd-user/elfload.c
> +++ b/bsd-user/elfload.c
> @@ -641,8 +641,7 @@ static abi_ulong copy_elf_strings(int argc,char ** argv, void **page,
>                   offset = p % TARGET_PAGE_SIZE;
>                   pag = (char *)page[p/TARGET_PAGE_SIZE];
>                   if (!pag) {
> -                    pag = (char *)malloc(TARGET_PAGE_SIZE);
> -                    memset(pag, 0, TARGET_PAGE_SIZE);
> +                    pag = g_try_malloc0(TARGET_PAGE_SIZE);
>                       page[p/TARGET_PAGE_SIZE] = pag;
>                       if (!pag)
>                           return 0;
> @@ -696,7 +695,7 @@ static abi_ulong setup_arg_pages(abi_ulong p, struct linux_binprm *bprm,
>               info->rss++;
>               /* FIXME - check return value of memcpy_to_target() for failure */
>               memcpy_to_target(stack_base, bprm->page[i], TARGET_PAGE_SIZE);
> -            free(bprm->page[i]);
> +            g_free(bprm->page[i]);
>           }
>           stack_base += TARGET_PAGE_SIZE;
>       }
>    

Ping? Can this be fixed in QEMU 1.0?