From: Chris Allegretta Date: Wed, 7 Apr 2010 05:48:24 +0000 (+0000) Subject: * files.c (do_writeout): Also abort on writing a backup X-Git-Tag: v2.2.4~12 X-Git-Url: https://git.wh0rd.org/?a=commitdiff_plain;h=0d1381adf9666e11bfaa6379549bc81cb2328e72;p=nano.git * files.c (do_writeout): Also abort on writing a backup file when its owner doesn't match the edited file. git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@4491 35c25a1d-7b9e-4130-9fde-d3aeb78583b8 --- diff --git a/ChangeLog b/ChangeLog index 3c4edf96..fceeddaf 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,8 +1,9 @@ 2010-04-02 Chris Allegretta * files.c (do_writeout): Expand modification check to include both the original file's device ID and inode number as reasons to warn the - user that the file has been modified. Based on security article on nano - by Dan Rosenberg. + user that the file has been modified. Also abort on writing a backup + file when its owner doesn't match the edited file. Based on security + analysis on nano by Dan Rosenberg. 2010-03-21 Chris Allegretta * nano.c (page_stdin et al): Don't attempt to reset/reopen the terminal diff --git a/src/files.c b/src/files.c index 8e63903a..632c0f9a 100644 --- a/src/files.c +++ b/src/files.c @@ -1519,6 +1519,7 @@ bool write_file(const char *name, FILE *f_open, bool tmp, append_type char *backupname; struct utimbuf filetime; int copy_status; + struct stat backupst; /* Save the original file's access and modification times. */ filetime.actime = openfile->current_stat->st_atime; @@ -1588,6 +1589,15 @@ bool write_file(const char *name, FILE *f_open, bool tmp, append_type sprintf(backupname, "%s~", realname); } + if (stat(backupname, &backupst) != -1 && + (backupst.st_uid != st.st_uid)) { + statusbar(_("Error writing backup file %s: Permission mismatch"), backupname, + strerror(errno)); + free(backupname); + goto cleanup_and_exit; + } + + /* Open the destination backup file. Before we write to it, we * set its permissions, so no unauthorized person can read it as * we write. */