From c6dfed243e0310bc3294c0fdf1816fceab024e9b Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Wed, 22 Oct 2014 13:17:20 -0700 Subject: [PATCH] Rework some nscd code not to use variable-length struct types. --- ChangeLog | 13 ++++ inet/netgroup.h | 2 +- nscd/netgroupcache.c | 14 ++-- nscd/nscd.c | 164 +++++++++++++++++++++++-------------------- nscd/nscd_helper.c | 17 ++--- 5 files changed, 117 insertions(+), 93 deletions(-) diff --git a/ChangeLog b/ChangeLog index e7fc13428c..b7eca45fbd 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,16 @@ +2014-10-22 Roland McGrath + + * inet/netgroup.h (struct name_list): Use C99 [] syntax rather than + old GNU extension [0] syntax. + * nscd/nscd_helper.c (open_socket): Use a flexible array member and + alloca rather than an array member with variable length. + * nscd/netgroupcache.c (addgetnetgrentX): Likewise. + * nscd/nscd.c (invalidate_db): New function, broken out of ... + (parse_opt): ... here. Likewise use alloca there. + Validate the -i argument before checking for rootness. + (send_shutdown): New function, broken out of ... + (parse_opt): ... here. + 2014-10-22 Roland McGrath * sysdeps/arm/__longjmp.S [NEED_HWCAP] [IS_IN_rtld]: Use LDST_PCREL diff --git a/inet/netgroup.h b/inet/netgroup.h index 490004589d..f772a09d82 100644 --- a/inet/netgroup.h +++ b/inet/netgroup.h @@ -26,7 +26,7 @@ struct name_list { struct name_list *next; - char name[0]; + char name[]; }; diff --git a/nscd/netgroupcache.c b/nscd/netgroupcache.c index edab1744f4..9910c57ec2 100644 --- a/nscd/netgroupcache.c +++ b/nscd/netgroupcache.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include @@ -136,11 +137,8 @@ addgetnetgrentX (struct database_dyn *db, int fd, request_header *req, char *buffer = NULL; size_t nentries = 0; size_t group_len = strlen (key) + 1; - union - { - struct name_list elem; - char mem[sizeof (struct name_list) + group_len]; - } first_needed; + struct name_list *first_needed + = alloca (sizeof (struct name_list) + group_len); if (netgroup_database == NULL && __nss_database_lookup ("netgroup", NULL, NULL, &netgroup_database)) @@ -153,9 +151,9 @@ addgetnetgrentX (struct database_dyn *db, int fd, request_header *req, memset (&data, '\0', sizeof (data)); buffer = xmalloc (buflen); - first_needed.elem.next = &first_needed.elem; - memcpy (first_needed.elem.name, key, group_len); - data.needed_groups = &first_needed.elem; + first_needed->next = first_needed; + memcpy (first_needed->name, key, group_len); + data.needed_groups = first_needed; while (data.needed_groups != NULL) { diff --git a/nscd/nscd.c b/nscd/nscd.c index b7704b37f8..1185ed6647 100644 --- a/nscd/nscd.c +++ b/nscd/nscd.c @@ -324,6 +324,75 @@ main (int argc, char **argv) } +static void __attribute__ ((noreturn)) +invalidate_db (const char *dbname) +{ + int sock = nscd_open_socket (); + + if (sock == -1) + exit (EXIT_FAILURE); + + size_t dbname_len = strlen (dbname) + 1; + size_t reqlen = sizeof (request_header) + dbname_len; + struct + { + request_header req; + char dbname[]; + } *reqdata = alloca (reqlen); + + reqdata->req.key_len = dbname_len; + reqdata->req.version = NSCD_VERSION; + reqdata->req.type = INVALIDATE; + memcpy (reqdata->dbname, dbname, dbname_len); + + ssize_t nbytes = TEMP_FAILURE_RETRY (send (sock, reqdata, reqlen, + MSG_NOSIGNAL)); + + if (nbytes != reqlen) + { + int err = errno; + close (sock); + error (EXIT_FAILURE, err, _("write incomplete")); + } + + /* Wait for ack. Older nscd just closed the socket when + prune_cache finished, silently ignore that. */ + int32_t resp = 0; + nbytes = TEMP_FAILURE_RETRY (read (sock, &resp, sizeof (resp))); + if (nbytes != 0 && nbytes != sizeof (resp)) + { + int err = errno; + close (sock); + error (EXIT_FAILURE, err, _("cannot read invalidate ACK")); + } + + close (sock); + + if (resp != 0) + error (EXIT_FAILURE, resp, _("invalidation failed")); + + exit (0); +} + +static void __attribute__ ((noreturn)) +send_shutdown (void) +{ + int sock = nscd_open_socket (); + + if (sock == -1) + exit (EXIT_FAILURE); + + request_header req; + req.version = NSCD_VERSION; + req.type = SHUTDOWN; + req.key_len = 0; + + ssize_t nbytes = TEMP_FAILURE_RETRY (send (sock, &req, sizeof req, + MSG_NOSIGNAL)); + close (sock); + exit (nbytes != sizeof (request_header) ? EXIT_FAILURE : EXIT_SUCCESS); +} + /* Handle program arguments. */ static error_t parse_opt (int key, char *arg, struct argp_state *state) @@ -346,91 +415,34 @@ parse_opt (int key, char *arg, struct argp_state *state) case 'K': if (getuid () != 0) error (4, 0, _("Only root is allowed to use this option!")); - { - int sock = nscd_open_socket (); - - if (sock == -1) - exit (EXIT_FAILURE); - - request_header req; - req.version = NSCD_VERSION; - req.type = SHUTDOWN; - req.key_len = 0; - - ssize_t nbytes = TEMP_FAILURE_RETRY (send (sock, &req, - sizeof (request_header), - MSG_NOSIGNAL)); - close (sock); - exit (nbytes != sizeof (request_header) ? EXIT_FAILURE : EXIT_SUCCESS); - } + else + send_shutdown (); + break; case 'g': get_stats = true; break; case 'i': + { + /* Validate the database name. */ + + dbtype cnt; + for (cnt = pwddb; cnt < lastdb; ++cnt) + if (strcmp (arg, dbnames[cnt]) == 0) + break; + + if (cnt == lastdb) + { + argp_error (state, _("'%s' is not a known database"), arg); + return EINVAL; + } + } if (getuid () != 0) error (4, 0, _("Only root is allowed to use this option!")); else - { - int sock = nscd_open_socket (); - - if (sock == -1) - exit (EXIT_FAILURE); - - dbtype cnt; - for (cnt = pwddb; cnt < lastdb; ++cnt) - if (strcmp (arg, dbnames[cnt]) == 0) - break; - - if (cnt == lastdb) - { - argp_error (state, _("'%s' is not a known database"), arg); - return EINVAL; - } - - size_t arg_len = strlen (arg) + 1; - struct - { - request_header req; - char arg[arg_len]; - } reqdata; - - reqdata.req.key_len = strlen (arg) + 1; - reqdata.req.version = NSCD_VERSION; - reqdata.req.type = INVALIDATE; - memcpy (reqdata.arg, arg, arg_len); - - ssize_t nbytes = TEMP_FAILURE_RETRY (send (sock, &reqdata, - sizeof (request_header) - + arg_len, - MSG_NOSIGNAL)); - - if (nbytes != sizeof (request_header) + arg_len) - { - int err = errno; - close (sock); - error (EXIT_FAILURE, err, _("write incomplete")); - } - - /* Wait for ack. Older nscd just closed the socket when - prune_cache finished, silently ignore that. */ - int32_t resp = 0; - nbytes = TEMP_FAILURE_RETRY (read (sock, &resp, sizeof (resp))); - if (nbytes != 0 && nbytes != sizeof (resp)) - { - int err = errno; - close (sock); - error (EXIT_FAILURE, err, _("cannot read invalidate ACK")); - } - - close (sock); - - if (resp != 0) - error (EXIT_FAILURE, resp, _("invalidation failed")); - - exit (0); - } + invalidate_db (arg); + break; case 't': nthreads = atol (arg); diff --git a/nscd/nscd_helper.c b/nscd/nscd_helper.c index 9fe1f46156..ee3b67f03d 100644 --- a/nscd/nscd_helper.c +++ b/nscd/nscd_helper.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -186,12 +187,12 @@ open_socket (request_type type, const char *key, size_t keylen) if (sock < 0) return -1; + size_t real_sizeof_reqdata = sizeof (request_header) + keylen; struct { request_header req; - char key[keylen]; - } reqdata; - size_t real_sizeof_reqdata = sizeof (request_header) + keylen; + char key[]; + } *reqdata = alloca (real_sizeof_reqdata); #ifndef __ASSUME_SOCK_CLOEXEC # ifdef SOCK_NONBLOCK @@ -208,11 +209,11 @@ open_socket (request_type type, const char *key, size_t keylen) && errno != EINPROGRESS) goto out; - reqdata.req.version = NSCD_VERSION; - reqdata.req.type = type; - reqdata.req.key_len = keylen; + reqdata->req.version = NSCD_VERSION; + reqdata->req.type = type; + reqdata->req.key_len = keylen; - memcpy (reqdata.key, key, keylen); + memcpy (reqdata->key, key, keylen); bool first_try = true; struct timeval tvend; @@ -223,7 +224,7 @@ open_socket (request_type type, const char *key, size_t keylen) #ifndef MSG_NOSIGNAL # define MSG_NOSIGNAL 0 #endif - ssize_t wres = TEMP_FAILURE_RETRY (__send (sock, &reqdata, + ssize_t wres = TEMP_FAILURE_RETRY (__send (sock, reqdata, real_sizeof_reqdata, MSG_NOSIGNAL)); if (__glibc_likely (wres == (ssize_t) real_sizeof_reqdata))