edit_sudoers: Check for read() error

millert · millert · commit a642d9802d94 · 2025-12-26T13:37:16.000-07:00
Found by the ZeroPath AI Security Engineer <https://zeropath.com>
diff --git a/plugins/sudoers/visudo.c b/plugins/sudoers/visudo.c
@@ -521,6 +521,10 @@ edit_sudoers(struct sudoersfile *sp, char *editor, int editor_argc,
 		}
 		lastch = buf[nread - 1];
 	    }
+	    if (nread == -1) {
+		sudo_warn(U_("%s: read error"), sp->opath);
+		goto done;
+	    }
 
 	    /* Add missing newline at EOF if needed. */
 	    if (lastch != '\n') {

Original file line number	Diff line number	Diff line change
`@@ -521,6 +521,10 @@ edit_sudoers(struct sudoersfile sp, char editor, int editor_argc,`
`521`	`521`	`}`
`522`	`522`	`lastch = buf[nread - 1];`
`523`	`523`	`}`
	`524`	`+ if (nread == -1) {`
	`525`	`+ sudo_warn(U_("%s: read error"), sp->opath);`
	`526`	`+ goto done;`
	`527`	`+ }`
`524`	`528`
`525`	`529`	`/* Add missing newline at EOF if needed. */`
`526`	`530`	`if (lastch != '\n') {`