diff options
| author | Lennart Poettering <lennart@poettering.net> | 2016-02-10 22:58:41 +0100 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2016-02-10 23:42:34 +0100 |
| commit | cf3bdcfeba48ffef71f1f59e092c4fb9275dcb3a (patch) | |
| tree | c6de01115847ac95b2a33fc185740bf68c4e4b91 /src | |
| parent | 648b122045182a1ac19d1622817e2a350beb0354 (diff) | |
nss-mymachines: never resolve unmapped UIDs/GIDs
Don't ever permit successful user or group lookups if no UID/GID mapping is
actually applied. THis way, we can be sure that nss-mymachines cannot be used
to insert invalid cache entries into nscd's cache.
https://bugzilla.redhat.com/show_bug.cgi?id=1285339
Diffstat (limited to 'src')
| -rw-r--r-- | src/nss-mymachines/nss-mymachines.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/src/nss-mymachines/nss-mymachines.c b/src/nss-mymachines/nss-mymachines.c index 78133a39bf..1582d702f8 100644 --- a/src/nss-mymachines/nss-mymachines.c +++ b/src/nss-mymachines/nss-mymachines.c @@ -38,6 +38,9 @@ NSS_GETHOSTBYNAME_PROTOTYPES(mymachines); NSS_GETPW_PROTOTYPES(mymachines); NSS_GETGR_PROTOTYPES(mymachines); +#define HOST_UID_LIMIT ((uid_t) UINT32_C(0x10000)) +#define HOST_GID_LIMIT ((gid_t) UINT32_C(0x10000)) + static int count_addresses(sd_bus_message *m, int af, unsigned *ret) { unsigned c = 0; int r; @@ -455,6 +458,10 @@ enum nss_status _nss_mymachines_getpwnam_r( if (r < 0) goto fail; + /* Refuse to work if the mapped address is in the host UID range, or if there was no mapping at all. */ + if (mapped < HOST_UID_LIMIT || mapped == uid) + goto not_found; + l = strlen(name); if (buflen < l+1) { *errnop = ENOMEM; @@ -504,7 +511,7 @@ enum nss_status _nss_mymachines_getpwuid_r( } /* We consider all uids < 65536 host uids */ - if (uid < 0x10000) + if (uid < HOST_UID_LIMIT) goto not_found; r = sd_bus_open_system(&bus); @@ -531,6 +538,9 @@ enum nss_status _nss_mymachines_getpwuid_r( if (r < 0) goto fail; + if (mapped == uid) + goto not_found; + if (snprintf(buffer, buflen, "vu-%s-" UID_FMT, machine, (uid_t) mapped) >= (int) buflen) { *errnop = ENOMEM; return NSS_STATUS_TRYAGAIN; @@ -619,6 +629,9 @@ enum nss_status _nss_mymachines_getgrnam_r( if (r < 0) goto fail; + if (mapped < HOST_GID_LIMIT || mapped == gid) + goto not_found; + l = sizeof(char*) + strlen(name) + 1; if (buflen < l) { *errnop = ENOMEM; @@ -666,7 +679,7 @@ enum nss_status _nss_mymachines_getgrgid_r( } /* We consider all gids < 65536 host gids */ - if (gid < 0x10000) + if (gid < HOST_GID_LIMIT) goto not_found; r = sd_bus_open_system(&bus); @@ -693,6 +706,9 @@ enum nss_status _nss_mymachines_getgrgid_r( if (r < 0) goto fail; + if (mapped == gid) + goto not_found; + if (buflen < sizeof(char*) + 1) { *errnop = ENOMEM; return NSS_STATUS_TRYAGAIN; |