On Friday, May 10, 2019 4:11:45 PM CEST Bruno Haible wrote:
> Kamil Dudka wrote:
> > Thanks! This also helps to suppress the false positives on cryptsetup
> > with Coverity Static Analysis version 2019.03.
>
> Good! Since this is the approach that Paul prefers, I'm pushing this one:
>
>
> 2019-05-10 Bruno Haible <br...@clisp.org>
>
> base64: Avoid false positive warning from Coverity.
> Reported by Kamil Dudka <kdu...@redhat.com>.
> Idea by Paul Eggert.
> * lib/base64.c (base64_encode_fast, base64_encode): Add a no-op
> '& 0x3f' to the array index expressions. This convinces Coverity that
> there is no out-of-bounds array reference, regardless of the input.
>
> diff --git a/lib/base64.c b/lib/base64.c
> index f3f7298..a00e0f4 100644
> --- a/lib/base64.c
> +++ b/lib/base64.c
> @@ -70,7 +70,7 @@ base64_encode_fast (const char *restrict in, size_t inlen,
> char *restrict out) {
> while (inlen)
> {
> - *out++ = b64c[to_uchar (in[0]) >> 2];
> + *out++ = b64c[(to_uchar (in[0]) >> 2) & 0x3f];
> *out++ = b64c[((to_uchar (in[0]) << 4) + (to_uchar (in[1]) >> 4)) &
> 0x3f]; *out++ = b64c[((to_uchar (in[1]) << 2) + (to_uchar (in[2]) >> 6)) &
> 0x3f]; *out++ = b64c[to_uchar (in[2]) & 0x3f];
> @@ -103,7 +103,7 @@ base64_encode (const char *restrict in, size_t inlen,
>
> while (inlen && outlen)
> {
> - *out++ = b64c[to_uchar (in[0]) >> 2];
> + *out++ = b64c[(to_uchar (in[0]) >> 2) & 0x3f];
> if (!--outlen)
> break;
> *out++ = b64c[((to_uchar (in[0]) << 4)
Works for me. Thanks to both of you!
Kamil
