we only write to writable files, so use O_WRONLY.

st_size is only meaningful for regular files, so check S_ISREG

diff --git a/usr.bin/signify/signify.c b/usr.bin/signify/signify.c
index 03d3886..15bd6dc 100644 (file)
--- a/usr.bin/signify/signify.c
+++ b/usr.bin/signify/signify.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: signify.c,v 1.29 2014/01/11 04:29:07 lteo Exp $ */
+/* $OpenBSD: signify.c,v 1.30 2014/01/12 21:18:52 tedu Exp $ */
 /*
  * Copyright (c) 2013 Ted Unangst <tedu@openbsd.org>
  *
@@ -170,6 +170,8 @@ readmsg(const char *filename, unsigned long long *msglenp)
        fd = xopen(filename, O_RDONLY | O_NOFOLLOW, 0);
        if (fstat(fd, &sb) == -1)
                err(1, "fstat on %s", filename);
+       if (!S_ISREG(sb.st_mode))
+               errx(1, "%s must be a regular file", filename);
        msglen = sb.st_size;
        if (msglen > (1UL << 30))
                errx(1, "msg too large in %s", filename);
@@ -200,7 +202,7 @@ appendall(const char *filename, const void *buf, size_t len)
 {
        int fd;
 
-       fd = xopen(filename, O_NOFOLLOW | O_RDWR | O_APPEND, 0);
+       fd = xopen(filename, O_NOFOLLOW | O_WRONLY | O_APPEND, 0);
        writeall(fd, buf, len, filename);
        close(fd);
 }
@@ -213,7 +215,7 @@ writeb64file(const char *filename, const char *comment, const void *buf,
        char b64[1024];
        int fd, rv;
 
-       fd = xopen(filename, O_CREAT|flags|O_NOFOLLOW|O_RDWR, mode);
+       fd = xopen(filename, O_CREAT|flags|O_NOFOLLOW|O_WRONLY, mode);
        snprintf(header, sizeof(header), "%s%s\n", COMMENTHDR,
            comment);
        writeall(fd, header, strlen(header), filename);
@@ -421,7 +423,7 @@ verify(const char *pubkeyfile, const char *msgfile, const char *sigfile,
 
        verifymsg(pubkey.pubkey, msg, msglen, sig.sig);
        if (embedded) {
-               fd = xopen(msgfile, O_CREAT|O_TRUNC|O_NOFOLLOW|O_RDWR, 0666);
+               fd = xopen(msgfile, O_CREAT|O_TRUNC|O_NOFOLLOW|O_WRONLY, 0666);
                writeall(fd, msg, msglen, msgfile);
                close(fd);
        }