[dm-devel] [PATCH v2 08/21] libmultipath (coverity): fix tainted values in alua_rtpg.c
Benjamin Marzinski
bmarzins at redhat.com
Wed Dec 1 19:08:28 UTC 2021
On Wed, Dec 01, 2021 at 01:36:37PM +0100, mwilck at suse.com wrote:
> From: Martin Wilck <mwilck at suse.com>
>
> Coverity needs tainted values limited by constant expressions.
>
> Signed-off-by: Martin Wilck <mwilck at suse.com>
Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
> ---
> libmultipath/prioritizers/alua_rtpg.c | 13 ++++----
> libmultipath/prioritizers/alua_spc3.h | 43 +++++++++++++++++++++++----
> 2 files changed, 43 insertions(+), 13 deletions(-)
>
> diff --git a/libmultipath/prioritizers/alua_rtpg.c b/libmultipath/prioritizers/alua_rtpg.c
> index 420a2e3..3f9c0e7 100644
> --- a/libmultipath/prioritizers/alua_rtpg.c
> +++ b/libmultipath/prioritizers/alua_rtpg.c
> @@ -27,7 +27,6 @@
> #include "../structs.h"
> #include "../prio.h"
> #include "../discovery.h"
> -#include "../unaligned.h"
> #include "../debug.h"
> #include "alua_rtpg.h"
>
> @@ -252,12 +251,12 @@ int
> get_target_port_group(const struct path * pp, unsigned int timeout)
> {
> unsigned char *buf;
> - struct vpd83_data * vpd83;
> - struct vpd83_dscr * dscr;
> + const struct vpd83_data * vpd83;
> + const struct vpd83_dscr * dscr;
> int rc;
> int buflen, scsi_buflen;
>
> - buflen = 4096;
> + buflen = VPD_BUFLEN;
> buf = (unsigned char *)malloc(buflen);
> if (!buf) {
> PRINT_DEBUG("malloc failed: could not allocate"
> @@ -298,13 +297,13 @@ get_target_port_group(const struct path * pp, unsigned int timeout)
> rc = -RTPG_NO_TPG_IDENTIFIER;
> FOR_EACH_VPD83_DSCR(vpd83, dscr) {
> if (vpd83_dscr_istype(dscr, IDTYPE_TARGET_PORT_GROUP)) {
> - struct vpd83_tpg_dscr *p;
> + const struct vpd83_tpg_dscr *p;
> if (rc != -RTPG_NO_TPG_IDENTIFIER) {
> PRINT_DEBUG("get_target_port_group: more "
> "than one TPG identifier found!");
> continue;
> }
> - p = (struct vpd83_tpg_dscr *)dscr->data;
> + p = (const struct vpd83_tpg_dscr *)dscr->data;
> rc = get_unaligned_be16(p->tpg);
> }
> }
> @@ -377,7 +376,7 @@ get_asymmetric_access_state(const struct path *pp, unsigned int tpg,
> uint64_t scsi_buflen;
> int fd = pp->fd;
>
> - buflen = 4096;
> + buflen = VPD_BUFLEN;
> buf = (unsigned char *)malloc(buflen);
> if (!buf) {
> PRINT_DEBUG ("malloc failed: could not allocate"
> diff --git a/libmultipath/prioritizers/alua_spc3.h b/libmultipath/prioritizers/alua_spc3.h
> index 7ba2cf4..f0a4bc4 100644
> --- a/libmultipath/prioritizers/alua_spc3.h
> +++ b/libmultipath/prioritizers/alua_spc3.h
> @@ -14,6 +14,7 @@
> */
> #ifndef __SPC3_H__
> #define __SPC3_H__
> +#include "../unaligned.h"
>
> /*=============================================================================
> * Definitions to support the standard inquiry command as defined in SPC-3.
> @@ -177,7 +178,7 @@ struct vpd83_dscr {
> } __attribute__((packed));
>
> static inline int
> -vpd83_dscr_istype(struct vpd83_dscr *d, unsigned char type)
> +vpd83_dscr_istype(const struct vpd83_dscr *d, unsigned char type)
> {
> return ((d->b1 & 7) == type);
> }
> @@ -190,6 +191,38 @@ struct vpd83_data {
> struct vpd83_dscr data[0];
> } __attribute__((packed));
>
> +#define VPD_BUFLEN 4096
> +
> +/* Returns the max byte offset in the VPD page from the start of the page */
> +static inline unsigned int vpd83_max_offs(const struct vpd83_data *p)
> +{
> + uint16_t len = get_unaligned_be16(p->length) + 4;
> +
> + return len <= VPD_BUFLEN ? len : VPD_BUFLEN;
> +}
> +
> +static inline bool
> +vpd83_descr_fits(const struct vpd83_dscr *d, const struct vpd83_data *p)
> +{
> + ptrdiff_t max_offs = vpd83_max_offs(p);
> + ptrdiff_t offs = ((const char *)d - (const char *)p);
> +
> + /* make sure we can read d->length */
> + if (offs < 0 || offs > max_offs - 4)
> + return false;
> +
> + offs += d->length + 4;
> + return offs <= max_offs;
> +}
> +
> +static inline const struct vpd83_dscr *
> +vpd83_next_dscr(const struct vpd83_dscr *d, const struct vpd83_data *p)
> +{
> + ptrdiff_t offs = ((const char *)d - (const char *)p) + d->length + 4;
> +
> + return (const struct vpd83_dscr *)((const char *)p + offs);
> +}
> +
> /*-----------------------------------------------------------------------------
> * This macro should be used to walk through all identification descriptors
> * defined in the code page 0x83.
> @@ -199,11 +232,9 @@ struct vpd83_data {
> */
> #define FOR_EACH_VPD83_DSCR(p, d) \
> for( \
> - d = p->data; \
> - (((char *) d) - ((char *) p)) < \
> - get_unaligned_be16(p->length); \
> - d = (struct vpd83_dscr *) \
> - ((char *) d + d->length + 4) \
> + d = p->data; \
> + vpd83_descr_fits(d, p); \
> + d = vpd83_next_dscr(d, p) \
> )
>
> /*=============================================================================
> --
> 2.33.1
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