From b8018b973c7cefa5eb386540130fa47315b8e337 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Mon, 2 Oct 2017 16:26:37 +0200 Subject: [PATCH] scsi: scsi_devinfo: fixup string compare When checking the model and vendor string we need to use the minimum value of either string, otherwise we'll miss out on wildcard matches. And we should take care when matching with zero size strings; results might be unpredictable. With this patch the rules for matching devinfo strings are as follows: - Vendor strings must match exactly - Empty Model strings will only match if the devinfo model is also empty - Model strings shorter than the devinfo model string will not match Fixes: 5e7ff2c ("SCSI: fix new bug in scsi_dev_info_list string matching") Signed-off-by: Hannes Reinecke Reviewed-by: Alan Stern Reviewed-by: Bart Van Assche Reviewed-by: Johannes Thumshirn Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_devinfo.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c index 6858ad87dac1..d39b27cf8ed9 100644 --- a/drivers/scsi/scsi_devinfo.c +++ b/drivers/scsi/scsi_devinfo.c @@ -399,8 +399,8 @@ EXPORT_SYMBOL(scsi_dev_info_list_add_keyed); /** * scsi_dev_info_list_find - find a matching dev_info list entry. - * @vendor: vendor string - * @model: model (product) string + * @vendor: full vendor string + * @model: full model (product) string * @key: specify list to use * * Description: @@ -415,7 +415,7 @@ static struct scsi_dev_info_list *scsi_dev_info_list_find(const char *vendor, struct scsi_dev_info_list *devinfo; struct scsi_dev_info_list_table *devinfo_table = scsi_devinfo_lookup_by_key(key); - size_t vmax, mmax; + size_t vmax, mmax, mlen; const char *vskip, *mskip; if (IS_ERR(devinfo_table)) @@ -454,15 +454,18 @@ static struct scsi_dev_info_list *scsi_dev_info_list_find(const char *vendor, dev_info_list) { if (devinfo->compatible) { /* - * Behave like the older version of get_device_flags. + * vendor strings must be an exact match */ - if (memcmp(devinfo->vendor, vskip, vmax) || - (vmax < sizeof(devinfo->vendor) && - devinfo->vendor[vmax])) + if (vmax != strlen(devinfo->vendor) || + memcmp(devinfo->vendor, vskip, vmax)) continue; - if (memcmp(devinfo->model, mskip, mmax) || - (mmax < sizeof(devinfo->model) && - devinfo->model[mmax])) + + /* + * @model specifies the full string, and + * must be larger or equal to devinfo->model + */ + mlen = strlen(devinfo->model); + if (mmax < mlen || memcmp(devinfo->model, mskip, mlen)) continue; return devinfo; } else {