Merge duplicate host key file checks, based in part on a patch from Rob

Holland via bz #1348 .  Also checks for non-regular files during protocol
1 RSA auth.  ok djm@

1 files changed, 43 insertions, 2 deletions

diff --git a/usr.bin/ssh/auth.c b/usr.bin/ssh/auth.c
index afa4209edf2..63d9b14ce7f 100644
--- a/usr.bin/ssh/auth.c
+++ b/usr.bin/ssh/auth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.c,v 1.78 2007/09/21 08:15:29 djm Exp $ */
+/* $OpenBSD: auth.c,v 1.79 2008/07/02 12:03:51 dtucker Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -28,6 +28,7 @@
 #include <sys/param.h>
 
 #include <errno.h>
+#include <fcntl.h>
 #include <libgen.h>
 #include <login_cap.h>
 #include <paths.h>
@@ -319,7 +320,7 @@ check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
  *
  * Returns 0 on success and -1 on failure
  */
-int
+static int
 secure_filename(FILE *f, const char *file, struct passwd *pw,
     char *err, size_t errlen)
 {
@@ -379,6 +380,46 @@ secure_filename(FILE *f, const char *file, struct passwd *pw,
 	return 0;
 }
 
+FILE *
+auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
+{
+	char line[1024];
+	struct stat st;
+	int fd;
+	FILE *f;
+
+	/*
+	 * Open the file containing the authorized keys
+	 * Fail quietly if file does not exist
+	 */
+	if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1)
+		return NULL;
+
+	if (fstat(fd, &st) < 0) {
+		close(fd);
+		return NULL;
+	}
+	if (!S_ISREG(st.st_mode)) {
+		logit("User %s authorized keys %s is not a regular file",
+		    pw->pw_name, file);
+		close(fd);
+		return NULL;
+	}
+	unset_nonblock(fd);
+	if ((f = fdopen(fd, "r")) == NULL) {
+		close(fd);
+		return NULL;
+	}
+	if (options.strict_modes &&
+	    secure_filename(f, file, pw, line, sizeof(line)) != 0) {
+		fclose(f);
+		logit("Authentication refused: %s", line);
+		return NULL;
+	}
+
+	return f;
+}
+
 struct passwd *
 getpwnamallow(const char *user)
 {