diff options
| author | Alejandro Colomar <alx@kernel.org> | 2023-11-15 22:14:18 +0100 |
|---|---|---|
| committer | Alejandro Colomar <alx@kernel.org> | 2023-11-16 15:26:45 +0100 |
| commit | 8711bc63fef4c6e186039bfb1ed543485ae478db (patch) | |
| tree | b9b83e1eb9ca6117c0b69e370ff9869ec25e5a3a | |
| parent | 6907d3c960a0aa07123cea50dc1da2c2e735def1 (diff) | |
lib/: Remove off-by-one bugs in calls to strncpy(3)
We're not even zeroing the last byte after this call. This was a
completely gratuitous truncation of one byte, and the resulting
character array still wasn't guaranteed to be null terminated, because
strncpy(3) can't do that.
Just to clarify, none of these structures needed zeroing, as they are
treated as null-padded fixed-size character arrays. Calling strncpy(3)
was actually the correct call, and the only problem was unnecessarily
truncating strings by one byte more than necessary.
Cc: Matthew House <mattlloydhouse@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
| -rw-r--r-- | lib/log.c | 2 | ||||
| -rw-r--r-- | lib/utmp.c | 8 |
2 files changed, 5 insertions, 5 deletions
@@ -82,7 +82,7 @@ void dolastlog ( newlog.ll_time = ll_time; STRTCPY(newlog.ll_line, line); #if HAVE_LL_HOST - strncpy (newlog.ll_host, host, sizeof (newlog.ll_host) - 1); + strncpy(newlog.ll_host, host, sizeof(newlog.ll_host)); #endif if ( (lseek (fd, offset, SEEK_SET) != offset) || (write_full(fd, &newlog, sizeof newlog) == -1) @@ -262,25 +262,25 @@ static utent->ut_type = USER_PROCESS; #endif /* HAVE_STRUCT_UTMP_UT_TYPE */ utent->ut_pid = getpid (); - strncpy (utent->ut_line, line, sizeof (utent->ut_line) - 1); + strncpy(utent->ut_line, line, sizeof(utent->ut_line)); #ifdef HAVE_STRUCT_UTMP_UT_ID if (NULL != ut) { strncpy (utent->ut_id, ut->ut_id, sizeof (utent->ut_id)); } else { /* XXX - assumes /dev/tty?? */ - strncpy (utent->ut_id, line + 3, sizeof (utent->ut_id) - 1); + strncpy(utent->ut_id, line + 3, sizeof(utent->ut_id)); } #endif /* HAVE_STRUCT_UTMP_UT_ID */ #ifdef HAVE_STRUCT_UTMP_UT_NAME strncpy (utent->ut_name, name, sizeof (utent->ut_name)); #endif /* HAVE_STRUCT_UTMP_UT_NAME */ #ifdef HAVE_STRUCT_UTMP_UT_USER - strncpy (utent->ut_user, name, sizeof (utent->ut_user) - 1); + strncpy(utent->ut_user, name, sizeof(utent->ut_user)); #endif /* HAVE_STRUCT_UTMP_UT_USER */ if (NULL != hostname) { struct addrinfo *info = NULL; #ifdef HAVE_STRUCT_UTMP_UT_HOST - strncpy (utent->ut_host, hostname, sizeof (utent->ut_host) - 1); + strncpy(utent->ut_host, hostname, sizeof(utent->ut_host)); #endif /* HAVE_STRUCT_UTMP_UT_HOST */ #ifdef HAVE_STRUCT_UTMP_UT_SYSLEN utent->ut_syslen = MIN (strlen (hostname), |