On Mon, Dec 11, 2023 at 08:06:28PM +0000, Justin Stitt wrote:
> Instead of copying @buf into a new buffer and carefully managing its
> newline/null-terminating status, we can just use sysfs_match_string()
> as it uses sysfs_streq() internally which handles newline/null-term:
>
> | /**
> | * sysfs_streq - return true if strings are equal, modulo trailing newline
> | * @s1: one string
> | * @s2: another string
> | *
> | * This routine returns true iff two strings are equal, treating both
> | * NUL and newline-then-NUL as equivalent string terminations. It's
> | * geared for use with sysfs input strings, which generally terminate
> | * with newlines but are compared against values without newlines.
> | */
> | bool sysfs_streq(const char *s1, const char *s2)
> | ...
>
> Then entirely drop the now unused fcoe_parse_mode, being careful to
> change if condition from checking for FIP_CONN_TYPE_UNKNOWN to < 0 as
> sysfs_match_string can return -EINVAL.
>
> To get the compiler not to complain, make fip_conn_type_names
> const char * const. Perhaps, this should also be done for
> fcf_state_names.
>
> This also removes an instance of strncpy() which helps [1].
>
> Link: https://github.com/KSPP/linux/issues/90 [1]
> Cc: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> ---
> Builds upon patch and feedback from [2]:
>
> However, this is different enough to warrant its own patch and not be a
> continuation.
>
> [2]: https://lore.kernel.org/all/[email protected]/
> ---
> drivers/scsi/fcoe/fcoe_sysfs.c | 26 ++++----------------------
> 1 file changed, 4 insertions(+), 22 deletions(-)
My favorite kind of insert/delete ratio! :)
>
> diff --git a/drivers/scsi/fcoe/fcoe_sysfs.c b/drivers/scsi/fcoe/fcoe_sysfs.c
> index e17957f8085c..f9c5d00f658a 100644
> --- a/drivers/scsi/fcoe/fcoe_sysfs.c
> +++ b/drivers/scsi/fcoe/fcoe_sysfs.c
> @@ -10,6 +10,7 @@
> #include <linux/kernel.h>
> #include <linux/etherdevice.h>
> #include <linux/ctype.h>
> +#include <linux/string.h>
>
> #include <scsi/fcoe_sysfs.h>
> #include <scsi/libfcoe.h>
> @@ -214,25 +215,13 @@ static const char *get_fcoe_##title##_name(enum
> table_type table_key) \
> return table[table_key]; \
> }
>
> -static char *fip_conn_type_names[] = {
> +static const char * const fip_conn_type_names[] = {
> [ FIP_CONN_TYPE_UNKNOWN ] = "Unknown",
> [ FIP_CONN_TYPE_FABRIC ] = "Fabric",
> [ FIP_CONN_TYPE_VN2VN ] = "VN2VN",
> };
> fcoe_enum_name_search(ctlr_mode, fip_conn_type, fip_conn_type_names)
>
> -static enum fip_conn_type fcoe_parse_mode(const char *buf)
> -{
> - int i;
> -
> - for (i = 0; i < ARRAY_SIZE(fip_conn_type_names); i++) {
> - if (strcasecmp(buf, fip_conn_type_names[i]) == 0)
> - return i;
> - }
> -
> - return FIP_CONN_TYPE_UNKNOWN;
> -}
> -
> static char *fcf_state_names[] = {
> [ FCOE_FCF_STATE_UNKNOWN ] = "Unknown",
> [ FCOE_FCF_STATE_DISCONNECTED ] = "Disconnected",
> @@ -274,17 +263,10 @@ static ssize_t store_ctlr_mode(struct device *dev,
> const char *buf, size_t count)
> {
> struct fcoe_ctlr_device *ctlr = dev_to_ctlr(dev);
> - char mode[FCOE_MAX_MODENAME_LEN + 1];
>
> if (count > FCOE_MAX_MODENAME_LEN)
> return -EINVAL;
>
> - strncpy(mode, buf, count);
> -
> - if (mode[count - 1] == '\n')
> - mode[count - 1] = '\0';
> - else
> - mode[count] = '\0';
>
> switch (ctlr->enabled) {
> case FCOE_CTLR_ENABLED:
> @@ -297,8 +279,8 @@ static ssize_t store_ctlr_mode(struct device *dev,
> return -ENOTSUPP;
> }
>
> - ctlr->mode = fcoe_parse_mode(mode);
> - if (ctlr->mode == FIP_CONN_TYPE_UNKNOWN) {
> + ctlr->mode = sysfs_match_string(fip_conn_type_names, buf);
> + if (ctlr->mode < 0) {
I think this needs to include FIP_CONN_TYPE_UNKNOWN to keep the logic
the same? (i.e. it could match the string "Unknown", so it would return
the enum value for that, 0 in this case.)
Otherwise, yeah, this looks good.
-Kees
> LIBFCOE_SYSFS_DBG(ctlr, "Unknown mode %s provided.\n",
> buf);
> return -EINVAL;
>
> ---
> base-commit: bee0e7762ad2c6025b9f5245c040fcc36ef2bde8
> change-id: 20231024-strncpy-drivers-scsi-fcoe-fcoe_sysfs-c-0e1dffe82855
>
> Best regards,
> --
> Justin Stitt <[email protected]>
>
>
--
Kees Cook
