Hi,
On Sat, Oct 05, 2024 at 11:48:56AM -0400, Jeffrey Cliff wrote:
> URL:
> <https://savannah.gnu.org/bugs/?66296>
>
> Summary: rshd.c string overflow warning
Thanks for reporting an issue you encountered with GNU Inetutils!
> [...]
> Date: Sat 05 Oct 2024 10:48:53 AM CDT By: Jeffrey Cliff <themusicgod1>
> inetutils: 2.5
> gcc: (GCC) 15.0.0 20240509 (experimental)
>
> rshd.c:1923:3: warning: 'strncat' specified bound 13 equals source length
> [-Wstringop-overflow=]
> 1923 | strncat (path, PATH_DEFPATH, sizeof (path) - sizeof ("PATH=") - 1);
I'd say this is a wrong warning, because there is nothing wrong to warn
about. With "src" as long as "n", strncat appends all n bytes to "dest"
and adds a NUL byte. This requires the "dest" buffer to be one byte longer
than strlen(dest) + n. This is the case here, as can be seen from your
patch.
> if i'm reading this right, increasing the size of the "path" string by one
> should should fix this:
There is nothing to fix. Your patch just adds an usused byte to the "path"
buffer.
> --- inetutils-2.5/src/rshd.c 2023-12-29 11:34:46.000000000 -0600
> +++ inetutils-2.5-works/src/rshd.c 2024-10-05 09:47:18.126254725 -0600
> @@ -411,7 +411,7 @@
> char logname[32 + sizeof ("LOGNAME=")] = "LOGNAME=";
> char homedir[256 + sizeof ("HOME=")] = "HOME=";
> char shell[64 + sizeof ("SHELL=")] = "SHELL=";
> -char path[sizeof (PATH_DEFPATH) + sizeof ("PATH=")] = "PATH=";
> +char path[sizeof (PATH_DEFPATH) + sizeof ("PATH=")+1] = "PATH=";
> char rhost[128 + sizeof ("RHOST=")] = "RHOST=";
>
> #ifndef WITH_PAM
Thanks,
Erik
