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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2007-12-20 12:30:22 +0100 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2008-01-11 18:29:00 -0600 |
| commit | d1ad09db2fd551d49d65ef040591cb9298e70fb6 (patch) | |
| tree | e26e31c96068ce3ab58ed14d4e51d68a308d3891 | |
| parent | bfd90dce248a49ced2b7419ecf78af9f7f37039e (diff) | |
| download | linux-d1ad09db2fd551d49d65ef040591cb9298e70fb6.tar.bz2 | |
[SCSI] zfcp: fix use after free bug.
zfcp_erp_strategy_check_fsfreq() checks if it is safe to access the
fsf_req associated with the erp_action that gets passed. To test if
it is safe it accesses the fsf_req in order to get its index into
the hash list. This is broken since the fsf_req might be freed already
and the read index has no meaning. It could lead to memory corruption.
Fix this by introducing a new zfcp_reqlist_find_safe() method which
just checks if addresses are equal. This is slower, but only gets
called in case of error recovery.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
| -rw-r--r-- | drivers/s390/scsi/zfcp_def.h | 14 | ||||
| -rw-r--r-- | drivers/s390/scsi/zfcp_erp.c | 3 |
2 files changed, 16 insertions, 1 deletions
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h index 294d0792e82b..9e9f6c1e4e5d 100644 --- a/drivers/s390/scsi/zfcp_def.h +++ b/drivers/s390/scsi/zfcp_def.h @@ -1123,6 +1123,20 @@ zfcp_reqlist_find(struct zfcp_adapter *adapter, unsigned long req_id) return NULL; } +static inline struct zfcp_fsf_req * +zfcp_reqlist_find_safe(struct zfcp_adapter *adapter, struct zfcp_fsf_req *req) +{ + struct zfcp_fsf_req *request; + unsigned int idx; + + for (idx = 0; idx < REQUEST_LIST_SIZE; idx++) { + list_for_each_entry(request, &adapter->req_list[idx], list) + if (request == req) + return request; + } + return NULL; +} + /* * functions needed for reference/usage counting */ diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c index 67d74ed0f25c..76fef3f6387e 100644 --- a/drivers/s390/scsi/zfcp_erp.c +++ b/drivers/s390/scsi/zfcp_erp.c @@ -846,7 +846,8 @@ zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *erp_action) if (erp_action->fsf_req) { /* take lock to ensure that request is not deleted meanwhile */ spin_lock(&adapter->req_list_lock); - if (zfcp_reqlist_find(adapter, erp_action->fsf_req->req_id)) { + if (zfcp_reqlist_find_safe(adapter, erp_action->fsf_req) && + erp_action->fsf_req->erp_action == erp_action) { /* fsf_req still exists */ debug_text_event(adapter->erp_dbf, 3, "a_ca_req"); debug_event(adapter->erp_dbf, 3, &erp_action->fsf_req, |