- djm@cvs.openbsd.org 2012/10/30 21:29:55
[auth-rsa.c auth.c auth.h auth2-pubkey.c servconf.c servconf.h]
[sshd.c sshd_config sshd_config.5]
new sshd_config option AuthorizedKeysCommand to support fetching
authorized_keys from a command in addition to (or instead of) from
the filesystem. The command is run as the target server user unless
another specified via a new AuthorizedKeysCommandUser option.
patch originally by jchadima AT redhat.com, reworked by me; feedback
and ok markus@
diff --git a/auth.c b/auth.c
index a8cffd5..b5e1eef 100644
--- a/auth.c
+++ b/auth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.c,v 1.96 2012/05/13 01:42:32 dtucker Exp $ */
+/* $OpenBSD: auth.c,v 1.97 2012/10/30 21:29:54 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
*
@@ -409,41 +409,42 @@
return host_status;
}
-
/*
- * Check a given file for security. This is defined as all components
+ * Check a given path for security. This is defined as all components
* of the path to the file must be owned by either the owner of
* of the file or root and no directories must be group or world writable.
*
* XXX Should any specific check be done for sym links ?
*
- * Takes an open file descriptor, the file name, a uid and and
+ * Takes an the file name, its stat information (preferably from fstat() to
+ * avoid races), the uid of the expected owner, their home directory and an
* error buffer plus max size as arguments.
*
* Returns 0 on success and -1 on failure
*/
-static int
-secure_filename(FILE *f, const char *file, struct passwd *pw,
- char *err, size_t errlen)
+int
+auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
+ uid_t uid, char *err, size_t errlen)
{
- uid_t uid = pw->pw_uid;
char buf[MAXPATHLEN], homedir[MAXPATHLEN];
char *cp;
int comparehome = 0;
struct stat st;
- if (realpath(file, buf) == NULL) {
- snprintf(err, errlen, "realpath %s failed: %s", file,
+ if (realpath(name, buf) == NULL) {
+ snprintf(err, errlen, "realpath %s failed: %s", name,
strerror(errno));
return -1;
}
- if (realpath(pw->pw_dir, homedir) != NULL)
+ if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
comparehome = 1;
- /* check the open file to avoid races */
- if (fstat(fileno(f), &st) < 0 ||
- (st.st_uid != 0 && st.st_uid != uid) ||
- (st.st_mode & 022) != 0) {
+ if (!S_ISREG(stp->st_mode)) {
+ snprintf(err, errlen, "%s is not a regular file", buf);
+ return -1;
+ }
+ if ((stp->st_uid != 0 && stp->st_uid != uid) ||
+ (stp->st_mode & 022) != 0) {
snprintf(err, errlen, "bad ownership or modes for file %s",
buf);
return -1;
@@ -479,6 +480,28 @@
return 0;
}
+/*
+ * Version of secure_path() that accepts an open file descriptor to
+ * avoid races.
+ *
+ * Returns 0 on success and -1 on failure
+ */
+static int
+secure_filename(FILE *f, const char *file, struct passwd *pw,
+ char *err, size_t errlen)
+{
+ char buf[MAXPATHLEN];
+ struct stat st;
+
+ /* check the open file to avoid races */
+ if (fstat(fileno(f), &st) < 0) {
+ snprintf(err, errlen, "cannot stat file %s: %s",
+ buf, strerror(errno));
+ return -1;
+ }
+ return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
+}
+
static FILE *
auth_openfile(const char *file, struct passwd *pw, int strict_modes,
int log_missing, char *file_type)