iAvoid zero-length iowrite - sacc - sacc(omys), simple console gopher client	Err	bitreich.org	70
hgit clone git://bitreich.org/sacc/ git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/sacc/	URL:git://bitreich.org/sacc/ git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/sacc/	bitreich.org	70
1Log	/scm/sacc/log.gph	bitreich.org	70
1Files	/scm/sacc/files.gph	bitreich.org	70
1Refs	/scm/sacc/refs.gph	bitreich.org	70
1Tags	/scm/sacc/tag	bitreich.org	70
1LICENSE	/scm/sacc/file/LICENSE.gph	bitreich.org	70
i---	Err	bitreich.org	70
1commit 20a51bafd3906aa0337fe221d0981293d94370a5	/scm/sacc/commit/20a51bafd3906aa0337fe221d0981293d94370a5.gph	bitreich.org	70
1parent 21d46d603a3697f04072e4c0edb0076b4a215a2e	/scm/sacc/commit/21d46d603a3697f04072e4c0edb0076b4a215a2e.gph	bitreich.org	70
hAuthor: Michael Forney <mforney@mforney.org>	URL:mailto:mforney@mforney.org	bitreich.org	70
iDate:   Tue, 19 Mar 2024 14:52:09 -0700	Err	bitreich.org	70
i	Err	bitreich.org	70
iAvoid zero-length iowrite	Err	bitreich.org	70
i	Err	bitreich.org	70
iiowrite with bs==0 results in either a zero-length write() or	Err	bitreich.org	70
itls_write().	Err	bitreich.org	70
i	Err	bitreich.org	70
iThe former is unspecified by POSIX[0]:	Err	bitreich.org	70
i> If nbyte is zero and the file is not a regular file, the results	Err	bitreich.org	70
i> are unspecified.	Err	bitreich.org	70
i	Err	bitreich.org	70
iThe latter is not explicitly disallowed by tls_write(3), but libressl	Err	bitreich.org	70
iimplements tls_write with a call to SSL_write, which is documented	Err	bitreich.org	70
ito have undefined behavior[1]:	Err	bitreich.org	70
i> When calling SSL_write() with num=0 bytes to be sent, the behaviour	Err	bitreich.org	70
i> is undefined.	Err	bitreich.org	70
i	Err	bitreich.org	70
i[0] https://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html	Err	bitreich.org	70
i[1] https://man.openbsd.org/SSL_write.3	Err	bitreich.org	70
i	Err	bitreich.org	70
iDiffstat:	Err	bitreich.org	70
i  M sacc.c                              |       4 ++--	Err	bitreich.org	70
i	Err	bitreich.org	70
i1 file changed, 2 insertions(+), 2 deletions(-)	Err	bitreich.org	70
i---	Err	bitreich.org	70
1diff --git a/sacc.c b/sacc.c	/scm/sacc/file/sacc.c.gph	bitreich.org	70
i@@ -535,10 +535,10 @@ sendselector(struct cnx *c, const char *selector)	Err	bitreich.org	70
i         msg = p = xmalloc(ln);	Err	bitreich.org	70
i         snprintf(msg, ln--, "%s\r\n", selector);	Err	bitreich.org	70
i 	Err	bitreich.org	70
i-        while ((n = iowrite(c, p, ln)) > 0) {	Err	bitreich.org	70
i+        while (ln && (n = iowrite(c, p, ln)) > 0) {	Err	bitreich.org	70
i                 ln -= n;	Err	bitreich.org	70
i                 p += n;	Err	bitreich.org	70
i-        };	Err	bitreich.org	70
i+        }	Err	bitreich.org	70
i 	Err	bitreich.org	70
i         free(msg);	Err	bitreich.org	70
i         if (n == -1)	Err	bitreich.org	70
.