[PATCH] gdb/amd-dbgapi-target: assert register size in fetch/store_registers

[PATCH] gdb/amd-dbgapi-target: assert register size in fetch/store_registers

[Tankut Baris Aktemur]

Assert that register size is not larger than the max register size as
a safety measure against buffer overflow.
---
 gdb/amd-dbgapi-target.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/gdb/amd-dbgapi-target.c b/gdb/amd-dbgapi-target.c
index b7d5ee7de9f..421ec8599ed 100644
--- a/gdb/amd-dbgapi-target.c
+++ b/gdb/amd-dbgapi-target.c
@@ -1968,10 +1968,12 @@ amd_dbgapi_target::fetch_registers (struct regcache *regcache, int regno)
   amdgpu_gdbarch_tdep *tdep = get_amdgpu_gdbarch_tdep (gdbarch);
   amd_dbgapi_wave_id_t wave_id = get_amd_dbgapi_wave_id (regcache->ptid ());
   gdb_byte raw[AMDGPU_MAX_REGISTER_SIZE];
+  ULONGEST reg_size = register_type (gdbarch, regno)->length ();
+  gdb_assert (reg_size <= AMDGPU_MAX_REGISTER_SIZE);
+
   amd_dbgapi_status_t status
     = amd_dbgapi_read_register (wave_id, tdep->register_ids[regno], 0,
-				register_type (gdbarch, regno)->length (),
-				raw);
+				reg_size, raw);
 
   if (status == AMD_DBGAPI_STATUS_SUCCESS)
     regcache->raw_supply (regno, raw);
@@ -1994,6 +1996,8 @@ amd_dbgapi_target::store_registers (struct regcache *regcache, int regno)
   gdb_assert (is_amdgpu_arch (gdbarch));
 
   gdb_byte raw[AMDGPU_MAX_REGISTER_SIZE];
+  ULONGEST reg_size = register_type (gdbarch, regno)->length ();
+  gdb_assert (reg_size <= AMDGPU_MAX_REGISTER_SIZE);
   regcache->raw_collect (regno, &raw);
 
   amdgpu_gdbarch_tdep *tdep = get_amdgpu_gdbarch_tdep (gdbarch);
@@ -2018,8 +2022,7 @@ amd_dbgapi_target::store_registers (struct regcache *regcache, int regno)
   amd_dbgapi_wave_id_t wave_id = get_amd_dbgapi_wave_id (regcache->ptid ());
   amd_dbgapi_status_t status
     = amd_dbgapi_write_register (wave_id, tdep->register_ids[regno], 0,
-				 register_type (gdbarch, regno)->length (),
-				 raw);
+				 reg_size, raw);
 
   if (status != AMD_DBGAPI_STATUS_SUCCESS)
     warning (_("Couldn't write register %s (#%d)."),
-- 
2.34.1

Re: [PATCH] gdb/amd-dbgapi-target: assert register size in fetch/store_registers

[Lancelot SIX]

On 11/05/2026 12:58, Tankut Baris Aktemur wrote:
> Assert that register size is not larger than the max register size as
> a safety measure against buffer overflow.
> ---
>   gdb/amd-dbgapi-target.c | 11 +++++++----
>   1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/gdb/amd-dbgapi-target.c b/gdb/amd-dbgapi-target.c
> index b7d5ee7de9f..421ec8599ed 100644
> --- a/gdb/amd-dbgapi-target.c
> +++ b/gdb/amd-dbgapi-target.c
> @@ -1968,10 +1968,12 @@ amd_dbgapi_target::fetch_registers (struct regcache *regcache, int regno)
>     amdgpu_gdbarch_tdep *tdep = get_amdgpu_gdbarch_tdep (gdbarch);
>     amd_dbgapi_wave_id_t wave_id = get_amd_dbgapi_wave_id (regcache->ptid ());
>     gdb_byte raw[AMDGPU_MAX_REGISTER_SIZE];
> +  ULONGEST reg_size = register_type (gdbarch, regno)->length ();
> +  gdb_assert (reg_size <= AMDGPU_MAX_REGISTER_SIZE);
> +
>     amd_dbgapi_status_t status
>       = amd_dbgapi_read_register (wave_id, tdep->register_ids[regno], 0,
> -				register_type (gdbarch, regno)->length (),
> -				raw);
> +				reg_size, raw);
>   
>     if (status == AMD_DBGAPI_STATUS_SUCCESS)
>       regcache->raw_supply (regno, raw);
> @@ -1994,6 +1996,8 @@ amd_dbgapi_target::store_registers (struct regcache *regcache, int regno)
>     gdb_assert (is_amdgpu_arch (gdbarch));
>   
>     gdb_byte raw[AMDGPU_MAX_REGISTER_SIZE];
> +  ULONGEST reg_size = register_type (gdbarch, regno)->length ();
> +  gdb_assert (reg_size <= AMDGPU_MAX_REGISTER_SIZE);
>     regcache->raw_collect (regno, &raw);
>   
>     amdgpu_gdbarch_tdep *tdep = get_amdgpu_gdbarch_tdep (gdbarch);
> @@ -2018,8 +2022,7 @@ amd_dbgapi_target::store_registers (struct regcache *regcache, int regno)
>     amd_dbgapi_wave_id_t wave_id = get_amd_dbgapi_wave_id (regcache->ptid ());
>     amd_dbgapi_status_t status
>       = amd_dbgapi_write_register (wave_id, tdep->register_ids[regno], 0,
> -				 register_type (gdbarch, regno)->length (),
> -				 raw);
> +				 reg_size, raw);
>   
>     if (status != AMD_DBGAPI_STATUS_SUCCESS)
>       warning (_("Couldn't write register %s (#%d)."),

Hi Baris,

Thanks, this looks good to me, tested on gfx1031.

Approved-by: Lancelot Six <lancelot.six@amd.com>

Best,
Lancelot.