Re: [PATCH 2/6] imap-send.c, cram: allocate enough memory for null terminated string

From: Eric Sunshine <sunshine@sunshineco.com>
Date: Mar 30, 2016, 01:02 UTC
Message-ID: <CAPig+cSX4Jye60CKxR=OjhtAai09WSMNMOau2WHUxgXbKX2aDQ@mail.gmail.com>
In-Reply-To: <1459298333-21899-3-git-send-email-sbeller@google.com>

On Tue, Mar 29, 2016 at 8:38 PM, Stefan Beller <sbeller@google.com> wrote:

Show 19 quoted lines

> `strlen` returns the length of a string without the terminating null byte.
> To make sure enough memory is allocated we need to pass `strlen(..) + 1`
> to the allocation function.
>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
>  imap-send.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/imap-send.c b/imap-send.c
> index 2c52027..f7e9909 100644
> --- a/imap-send.c
> +++ b/imap-send.c
> @@ -872,7 +872,7 @@ static char *cram(const char *challenge_64, const char *user, const char *pass)
>          * enough upper bound for challenge (decoded result).
>          */
>         encoded_len = strlen(challenge_64);
> -       challenge = xmalloc(encoded_len);
> +       challenge = xmalloc(encoded_len + 1);

'challenge' is never used as a NUL-terminated string, and EVP_DecodeBlock() is not advertised as adding a terminating NUL, so why is this an improvement?

>         decoded_len = EVP_DecodeBlock((unsigned char *)challenge,
>                                       (unsigned char *)challenge_64, encoded_len);
>         if (decoded_len < 0)
> --