diff options
Diffstat (limited to 'sunrpc/auth_unix.c')
| -rw-r--r-- | sunrpc/auth_unix.c | 58 |
1 files changed, 48 insertions, 10 deletions
diff --git a/sunrpc/auth_unix.c b/sunrpc/auth_unix.c index 8c1134fba4..1cf18cb6b3 100644 --- a/sunrpc/auth_unix.c +++ b/sunrpc/auth_unix.c @@ -38,7 +38,9 @@ * for the credentials. */ +#include <errno.h> #include <limits.h> +#include <stdbool.h> #include <stdio.h> #include <string.h> #include <unistd.h> @@ -165,25 +167,61 @@ INTDEF (authunix_create) AUTH * authunix_create_default (void) { - int len; char machname[MAX_MACHINE_NAME + 1]; - uid_t uid; - gid_t gid; - int max_nr_groups = __sysconf (_SC_NGROUPS_MAX); - gid_t gids[max_nr_groups]; if (__gethostname (machname, MAX_MACHINE_NAME) == -1) abort (); machname[MAX_MACHINE_NAME] = 0; - uid = __geteuid (); - gid = __getegid (); + uid_t uid = __geteuid (); + gid_t gid = __getegid (); + + int max_nr_groups; + /* When we have to try a second time, do not use alloca() again. We + might have reached the stack limit already. */ + bool retry = false; + again: + /* Ask the kernel how many groups there are exactly. Note that we + might have to redo all this if the number of groups has changed + between the two calls. */ + max_nr_groups = __getgroups (0, NULL); + + /* Just some random reasonable stack limit. */ +#define ALLOCA_LIMIT (1024 / sizeof (gid_t)) + gid_t *gids = NULL; + if (max_nr_groups < ALLOCA_LIMIT && ! retry) + gids = (gid_t *) alloca (max_nr_groups * sizeof (gid_t)); + else + { + gids = (gid_t *) malloc (max_nr_groups * sizeof (gid_t)); + if (gids == NULL) + return NULL; + } + + int len = __getgroups (max_nr_groups, gids); + if (len == -1) + { + if (errno == EINVAL) + { + /* New groups added in the meantime. Try again. */ + if (max_nr_groups >= ALLOCA_LIMIT || retry) + free (gids); + retry = true; + goto again; + } + /* No other error can happen. */ + abort (); + } - if ((len = __getgroups (max_nr_groups, gids)) < 0) - abort (); /* This braindamaged Sun code forces us here to truncate the list of groups to NGRPS members since the code in authuxprot.c transforms a fixed array. Grrr. */ - return INTUSE(authunix_create) (machname, uid, gid, MIN (NGRPS, len), gids); + AUTH *result = INTUSE(authunix_create) (machname, uid, gid, MIN (NGRPS, len), + gids); + + if (max_nr_groups >= ALLOCA_LIMIT || retry) + free (gids); + + return result; } INTDEF (authunix_create_default) |