commit ec6d1a368f4f81cda70f8517eb0dec5028b847b8
from: Josh Rickmar <jrick@companyzero.com>
date: Sun Mar 21 18:49:57 2021 UTC

Fix strftime(3) short buffer checks

strftime(3) returns 0 if the buffer was too short to write the
complete string (including NUL) and will never return more than
maxsize-1.

ok stsp

commit - 4e20a6488836bfbb096ecad1bad212e094cc8624
commit + ec6d1a368f4f81cda70f8517eb0dec5028b847b8
blob - 9bcd279e5446ef8a890025dd5e3e16b3206fc66a
blob + 5a81fddc99d43b6d16f047c9a6ade37e0058f4e6
--- got/got.c
+++ got/got.c
@@ -4570,7 +4570,7 @@ blame_cb(void *arg, int nlines, int lineno, struct got
 	if (localtime_r(&committer_time, &tm) == NULL)
 		return got_error_from_errno("localtime_r");
 	if (strftime(bline->datebuf, sizeof(bline->datebuf), "%G-%m-%d",
-	    &tm) >= sizeof(bline->datebuf)) {
+	    &tm) == 0) {
 		err = got_error(GOT_ERR_NO_SPACE);
 		goto done;
 	}
@@ -10073,7 +10073,7 @@ print_path_info(void *arg, const char *path, mode_t mo
 	tm = localtime_r(&mtime, &mytm);
 	if (tm == NULL)
 		return NULL;
-	if (strftime(datebuf, sizeof(datebuf), "%c %Z", tm) >= sizeof(datebuf))
+	if (strftime(datebuf, sizeof(datebuf), "%c %Z", tm) == 0)
 		return got_error(GOT_ERR_NO_SPACE);
 	printf("timestamp: %s\n", datebuf);
 
blob - 5251b5a0c5366a6290eb08871fc51273ed568885
blob + 3b1cd05a35ea3d8b66188660baf875aca5f0f005
--- gotweb/gotweb.c
+++ gotweb/gotweb.c
@@ -3821,7 +3821,7 @@ gw_blame_cb(void *arg, int nlines, int lineno, struct 
 	if (localtime_r(&committer_time, &tm) == NULL)
 		return got_error_from_errno("localtime_r");
 	if (strftime(bline->datebuf, sizeof(bline->datebuf), "%G-%m-%d",
-	    &tm) >= sizeof(bline->datebuf)) {
+	    &tm) == 0) {
 		err = got_error(GOT_ERR_NO_SPACE);
 		goto done;
 	}
blob - 66c10afc613515bfc9122f54ffacf6671ce45f67
blob + c426e9d11b25926d3d473cea50910a6e8ecd3240
--- tog/tog.c
+++ tog/tog.c
@@ -1343,8 +1343,7 @@ draw_commit(struct tog_view *view, struct got_commit_o
 	committer_time = got_object_commit_get_committer_time(commit);
 	if (localtime_r(&committer_time, &tm) == NULL)
 		return got_error_from_errno("localtime_r");
-	if (strftime(datebuf, sizeof(datebuf), "%G-%m-%d ", &tm)
-	    >= sizeof(datebuf))
+	if (strftime(datebuf, sizeof(datebuf), "%G-%m-%d ", &tm) == 0)
 		return got_error(GOT_ERR_NO_SPACE);
 
 	if (avail <= date_display_cols)