diff options
author | dtucker@openbsd.org <dtucker@openbsd.org> | 2023-02-21 06:48:18 +0000 |
---|---|---|
committer | Darren Tucker <dtucker@dtucker.net> | 2023-02-21 18:28:26 +1100 |
commit | fe0bd3cde9665d364e5eedd2c2c2e60d4cdc3786 (patch) | |
tree | 23bd870da82beed9fc96f31d499e9659d14e567a | |
parent | 357fb8ae14c07cd025eeed66e73de91bab569849 (diff) |
upstream: fseek to end of known_hosts before writing to it.
POSIX and ANSI C require that applications call fseek or similar between
read and writing to a RW file. OpenBSD doesn't enforce this, but some
(System V derived) platforms need this to prevent it from writing a
spurious extra byte (in this case, a newline). ok djm@ deraadt@
OpenBSD-Commit-ID: 33e680dcd8110582a93a40a8491024e961f45137
-rw-r--r-- | hostfile.c | 17 |
1 files changed, 9 insertions, 8 deletions
@@ -1,4 +1,4 @@ -/* $OpenBSD: hostfile.c,v 1.94 2023/02/09 09:54:11 dtucker Exp $ */ +/* $OpenBSD: hostfile.c,v 1.95 2023/02/21 06:48:18 dtucker Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -515,7 +515,7 @@ add_host_to_hostfile(const char *filename, const char *host, const struct sshkey *key, int store_hash) { FILE *f; - int success; + int success, addnl = 0; if (key == NULL) return 1; /* XXX ? */ @@ -525,12 +525,13 @@ add_host_to_hostfile(const char *filename, const char *host, return 0; /* Make sure we have a terminating newline. */ if (fseek(f, -1L, SEEK_END) == 0 && fgetc(f) != '\n') - if (fputc('\n', f) != '\n') { - error("Failed to add terminating newline to %s: %s", - filename, strerror(errno)); - fclose(f); - return 0; - } + addnl = 1; + if (fseek(f, 0L, SEEK_END) != 0 || (addnl && fputc('\n', f) != '\n')) { + error("Failed to add terminating newline to %s: %s", + filename, strerror(errno)); + fclose(f); + return 0; + } success = write_host_entry(f, host, NULL, key, store_hash); fclose(f); return success; |