[Mesa-dev] [PATCH 2/2] intel/isl: Add bounds-checking assertions for the format_info table

[Jason Ekstrand]

We follow the same convention as isl_format_get_layout in having two
assertions to ensure that only valid formats are passed in.  We also
check against the array size of the table because some valid formats
such as CCS formats will may be past the end of the table.  This fixes
some potential out-of-bounds array access even in valid cases.

Cc: mesa-stable at lists.freedesktop.org
---
 src/intel/isl/isl_format.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/intel/isl/isl_format.c b/src/intel/isl/isl_format.c
index 52997cf2ebb..968f981cdee 100644
--- a/src/intel/isl/isl_format.c
+++ b/src/intel/isl/isl_format.c
@@ -374,11 +374,19 @@ format_gen(const struct gen_device_info *devinfo)
    return devinfo->gen * 10 + (devinfo->is_g4x || devinfo->is_haswell) * 5;
 }
 
+static bool
+format_info_exists(enum isl_format format)
+{
+   assert(format != ISL_FORMAT_UNSUPPORTED);
+   assert(format < ISL_NUM_FORMATS);
+   return format < ARRAY_SIZE(format_info) && format_info[format].exists;
+}
+
 bool
 isl_format_supports_rendering(const struct gen_device_info *devinfo,
                               enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    return format_gen(devinfo) >= format_info[format].render_target;
@@ -388,7 +396,7 @@ bool
 isl_format_supports_alpha_blending(const struct gen_device_info *devinfo,
                                    enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    return format_gen(devinfo) >= format_info[format].alpha_blend;
@@ -398,7 +406,7 @@ bool
 isl_format_supports_sampling(const struct gen_device_info *devinfo,
                              enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    if (devinfo->is_baytrail) {
@@ -431,7 +439,7 @@ bool
 isl_format_supports_filtering(const struct gen_device_info *devinfo,
                               enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    if (devinfo->is_baytrail) {
@@ -464,7 +472,7 @@ bool
 isl_format_supports_vertex_fetch(const struct gen_device_info *devinfo,
                                  enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    /* For vertex fetch, Bay Trail supports the same set of formats as Haswell
@@ -483,7 +491,7 @@ bool
 isl_format_supports_typed_writes(const struct gen_device_info *devinfo,
                                  enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    return format_gen(devinfo) >= format_info[format].typed_write;
@@ -504,7 +512,7 @@ bool
 isl_format_supports_typed_reads(const struct gen_device_info *devinfo,
                                 enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    return format_gen(devinfo) >= format_info[format].typed_read;
@@ -542,7 +550,7 @@ bool
 isl_format_supports_ccs_e(const struct gen_device_info *devinfo,
                           enum isl_format format)
 {
-   if (!format_info[format].exists)
+   if (!format_info_exists(format))
       return false;
 
    /* For simplicity, only report that a format supports CCS_E if blorp can
-- 
2.17.1