Re: [Qemu-devel] [PATCH] bsd_user: Fix potential null pointer dereference

[Peter Maydell]

On 21 November 2011 19:41, Stefan Weil <address@hidden> wrote:
> This bug was spotted by cppcheck.
>
> Using g_try_malloc0 (as does the linux-user code) fixes this.
>
> Signed-off-by: Stefan Weil <address@hidden>

Oh look, another bug in bsd-user it wouldn't have if it shared code
with linux-user :-)

>  bsd-user/elfload.c |    5 ++---
>  1 files changed, 2 insertions(+), 3 deletions(-)
>
> 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;
>     }

You've missed the s/free/g_free/ in bsd-user/bsdload.c. Compare
commit 7dd47667b.

-- PMM