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authorMichal Zidek <mzidek@redhat.com>2013-08-15 16:08:17 +0200
committerJakub Hrozek <jhrozek@redhat.com>2013-08-19 20:57:00 +0200
commitc49ddf7fee3c01e8a7d485b5fc06edf499df33cb (patch)
tree8ec3ec95d597d5d5a5aae1ece9194823abd1aedd
parentc58c458dc919104958454f33e6887791e5965a33 (diff)
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mmap_cache: Use better checks for corrupted mc in responder
We introduced new way to check integrity of memcache in the client code. We should use similiar checks in the responder.
-rw-r--r--src/responder/nss/nsssrv_mmap_cache.c56
-rw-r--r--src/util/mmap_cache.h2
2 files changed, 53 insertions, 5 deletions
diff --git a/src/responder/nss/nsssrv_mmap_cache.c b/src/responder/nss/nsssrv_mmap_cache.c
index e74c75c16..f523b4c54 100644
--- a/src/responder/nss/nsssrv_mmap_cache.c
+++ b/src/responder/nss/nsssrv_mmap_cache.c
@@ -356,6 +356,39 @@ static errno_t sss_mc_find_free_slots(struct sss_mc_ctx *mcc,
return EOK;
}
+static errno_t sss_mc_get_strs_offset(struct sss_mc_ctx *mcc,
+ size_t *_offset)
+{
+ switch (mcc->type) {
+ case SSS_MC_PASSWD:
+ *_offset = offsetof(struct sss_mc_pwd_data, strs);
+ return EOK;
+ case SSS_MC_GROUP:
+ *_offset = offsetof(struct sss_mc_grp_data, strs);
+ return EOK;
+ default:
+ DEBUG(SSSDBG_FATAL_FAILURE, ("Unknown memory cache type.\n"));
+ return EINVAL;
+ }
+}
+
+static errno_t sss_mc_get_strs_len(struct sss_mc_ctx *mcc,
+ struct sss_mc_rec *rec,
+ size_t *_len)
+{
+ switch (mcc->type) {
+ case SSS_MC_PASSWD:
+ *_len = ((struct sss_mc_pwd_data *)&rec->data)->strs_len;
+ return EOK;
+ case SSS_MC_GROUP:
+ *_len = ((struct sss_mc_grp_data *)&rec->data)->strs_len;
+ return EOK;
+ default:
+ DEBUG(SSSDBG_FATAL_FAILURE, ("Unknown memory cache type.\n"));
+ return EINVAL;
+ }
+}
+
static struct sss_mc_rec *sss_mc_find_record(struct sss_mc_ctx *mcc,
struct sized_string *key)
{
@@ -364,6 +397,10 @@ static struct sss_mc_rec *sss_mc_find_record(struct sss_mc_ctx *mcc,
uint32_t slot;
rel_ptr_t name_ptr;
char *t_key;
+ size_t strs_offset;
+ size_t strs_len;
+ uint8_t *max_addr;
+ errno_t ret;
hash = sss_mc_hash(mcc, key->str, key->len);
@@ -372,6 +409,14 @@ static struct sss_mc_rec *sss_mc_find_record(struct sss_mc_ctx *mcc,
return NULL;
}
+ /* Get max address of data table. */
+ max_addr = mcc->data_table + mcc->dt_size;
+
+ ret = sss_mc_get_strs_offset(mcc, &strs_offset);
+ if (ret != EOK) {
+ return NULL;
+ }
+
while (slot != MC_INVALID_VAL) {
if (!MC_SLOT_WITHIN_BOUNDS(slot, mcc->dt_size)) {
DEBUG(SSSDBG_FATAL_FAILURE,
@@ -381,10 +426,15 @@ static struct sss_mc_rec *sss_mc_find_record(struct sss_mc_ctx *mcc,
}
rec = MC_SLOT_TO_PTR(mcc->data_table, slot, struct sss_mc_rec);
+ ret = sss_mc_get_strs_len(mcc, rec, &strs_len);
+ if (ret != EOK) {
+ return NULL;
+ }
+
name_ptr = *((rel_ptr_t *)rec->data);
- /* FIXME: This check relies on fact that offset of member strs
- * is the same in structures sss_mc_pwd_data and sss_mc_group_data. */
- if (name_ptr != offsetof(struct sss_mc_pwd_data, strs)) {
+ if (key->len > strs_len
+ || (name_ptr + key->len) > (strs_offset + strs_len)
+ || (uint8_t *)rec->data + strs_offset + strs_len > max_addr) {
DEBUG(SSSDBG_FATAL_FAILURE,
("Corrupted fastcache. name_ptr value is %u.\n", name_ptr));
sss_mmap_cache_reset(mcc);
diff --git a/src/util/mmap_cache.h b/src/util/mmap_cache.h
index abf8cac49..7c6693ac8 100644
--- a/src/util/mmap_cache.h
+++ b/src/util/mmap_cache.h
@@ -113,8 +113,6 @@ struct sss_mc_rec {
char data[0];
};
-/* FIXME: Function sss_mc_find_record currently relies on fact that
- * offset of strs is the same in both sss_mc_pwd_data and sss_mc_grp_data. */
struct sss_mc_pwd_data {
rel_ptr_t name; /* ptr to name string, rel. to struct base addr */
uint32_t uid;