Hi there. update_usersfile does not only update the usersfile but also overwrites owner/permissions. this is bad (i think in general). in particular this is a show stopper for the private usersfile implementation (which is not complete yet).
the attached patch works around this in my case, but may fail. for example chown requires some privileges... i don't know how to seamlessly update a file in place, maybe the proper solution is to not replace that file at all. cheers felix
>From 6f49e1d7527cef3508bfc58cc2d1eb91e8663f61 Mon Sep 17 00:00:00 2001 From: Felix Salfelder <[email protected]> Date: Sat, 6 Dec 2014 23:13:06 +0100 Subject: [PATCH] restore mode/ownership after rewriting usersfile (workaround) --- liboath/oath.h.in | 4 +++- liboath/usersfile.c | 9 +++++++++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/liboath/oath.h.in b/liboath/oath.h.in index 173592a..8853a8e 100644 --- a/liboath/oath.h.in +++ b/liboath/oath.h.in @@ -91,6 +91,7 @@ extern "C" * @OATH_FILE_FLUSH_ERROR: System error when flushing file buffer * @OATH_FILE_SYNC_ERROR: System error when syncing file to disk * @OATH_FILE_CLOSE_ERROR: System error when closing file + * @OATH_FILE_MODE_ERROR: System error when closing file * @OATH_LAST_ERROR: Meta-error indicating the last error code, for use * when iterating over all error codes or similar. * @@ -129,9 +130,10 @@ typedef enum OATH_FILE_FLUSH_ERROR = -23, OATH_FILE_SYNC_ERROR = -24, OATH_FILE_CLOSE_ERROR = -25, + OATH_FILE_MODE_ERROR = -26, /* When adding anything here, update OATH_LAST_ERROR, errors.c and tests/tst_errors.c. */ - OATH_LAST_ERROR = -25 + OATH_LAST_ERROR = -26 } oath_rc; /* Global */ diff --git a/liboath/usersfile.c b/liboath/usersfile.c index 57d9e2a..d8121ce 100644 --- a/liboath/usersfile.c +++ b/liboath/usersfile.c @@ -308,6 +308,10 @@ update_usersfile (const char *usersfile, FILE *outfh, *lockfh; int rc; char *newfilename, *lockfile; + struct stat ufstat; + + if (fstat(fileno(infh), &ufstat)) + return OATH_FILE_SEEK_ERROR; /* Rewind input file. */ { @@ -389,6 +393,11 @@ update_usersfile (const char *usersfile, if (rc == OATH_OK && fsync (fileno (outfh)) != 0) rc = OATH_FILE_SYNC_ERROR; + /* set mode */ + if (fchmod(fileno(outfh), ufstat.st_mode) != 0 + ||fchown(fileno(outfh), ufstat.st_uid, ufstat.st_gid) != 0) + rc = OATH_FILE_MODE_ERROR; + /* Close the file regardless of success. */ if (fclose (outfh) != 0) rc = OATH_FILE_CLOSE_ERROR; -- 2.0.0
