[PATCH v2 4/4] stdio-common: Suppress Clang warnings on scanf13.c with fortify enable

[Sam James]

> On 10 Jan 2025, at 18:15, Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
> 
> clang-19 shows:
> 
> scanf13.c:28:40: error: 'sscanf' may overflow; destination buffer in argument 4 has size 8, but the corresponding specifier may require size 11 [-Werror,-Wfortify-source]
>   28 |               "A%ms%10ms%4m[bcd]%4mcB", &sp1, &sp2, &sp3, &sp4) != 4)
>      |                                               ^
> scanf13.c:94:34: error: 'sscanf' may overflow; destination buffer in argument 3 has size 8, but the corresponding specifier may require size 2049 [-Werror,-Wfortify-source]
>   94 |   if (sscanf (buf, "%2048ms%mc", &sp3, &sp4) != 2)
>      |                                  ^
> scanf13.c:110:61: error: 'sscanf' may overflow; destination buffer in argument 4 has size 8, but the corresponding specifier may require size 1501 [-Werror,-Wfortify-source]
>  110 |   if (sscanf (buf, "%4mc%1500m[dr/]%548m[abc/d]%3mc", &sp1, &sp2, &sp3, &sp4)
>      |                                                             ^
> scanf13.c:110:67: error: 'sscanf' may overflow; destination buffer in argument 5 has size 8, but the corresponding specifier may require size 549 [-Werror,-Wfortify-source]
>  110 |   if (sscanf (buf, "%4mc%1500m[dr/]%548m[abc/d]%3mc", &sp1, &sp2, &sp3, &sp4)
> ---
> stdio-common/scanf13.c | 5 +++++
> 1 file changed, 5 insertions(+)
> 
> diff --git a/stdio-common/scanf13.c b/stdio-common/scanf13.c
> index 65b1429720..131abb33de 100644
> --- a/stdio-common/scanf13.c
> +++ b/stdio-common/scanf13.c
> @@ -24,6 +24,7 @@ main (void)
>   DIAG_PUSH_NEEDS_COMMENT_CLANG;
>   DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wformat-invalid-specifier");
>   DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wformat-extra-args");
> +  DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wfortify-source");
>   if (sscanf ("A  \xc3\x84-\t\t\xc3\x84-abcdefbcd\t\xc3\x84-B",
>          "A%ms%10ms%4m[bcd]%4mcB", &sp1, &sp2, &sp3, &sp4) != 4)
>     FAIL ();
> @@ -91,6 +92,8 @@ main (void)
>    FAIL ();
>       free (sp2);
>     }
> +  DIAG_PUSH_NEEDS_COMMENT_CLANG;
> +  DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wfortify-source");
>   if (sscanf (buf, "%2048ms%mc", &sp3, &sp4) != 2)
>     FAIL ();
>   else
> @@ -131,6 +134,7 @@ main (void)
>    FAIL ();
>       free (sp4);
>     }
> +  DIAG_POP_NEEDS_COMMENT_CLANG;
>   if (sscanf (buf, "%mS%mC", &lsp1, &lsp2) != 2)
>     FAIL ();
>   else
> @@ -150,6 +154,7 @@ main (void)
>   DIAG_PUSH_NEEDS_COMMENT_CLANG;
>   DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wformat-invalid-specifier");
>   DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wformat-extra-args");
> +  DIAG_IGNORE_NEEDS_COMMENT_CLANG (13, "-Wfortify-source");
>   if (sscanf (buf, "%2048mls%mlc", &lsp3, &lsp4) != 2)
>     FAIL ();
>   else
> --

ok

> 2.43.0
>