Re: memset bugs.

Dave Jones <davej@codemonkey.org.uk> writes:
> A grep I crafted to pick up on some common bugs happened upon
> a copy of the FreeBSD CVS tree that I happened to have handy
> and found the bugs below where the 2nd & 3rd arguments to
> memset calls have been swapped.
> [...]
> --- src/sys/netinet/sctp_output.c~	2007-08-14 15:44:11.000000000 -0400
> +++ src/sys/netinet/sctp_output.c	2007-08-14 15:44:27.000000000 -0400
> @@ -6331,7 +6331,7 @@ out_gu:
>  		rcv_flags |=3D SCTP_DATA_UNORDERED;
>  	}
>  	/* clear out the chunk before setting up */
> -	memset(chk, sizeof(*chk), 0);
> +	memset(chk, 0, sizeof(*chk));
>  	chk->rec.data.rcv_flags =3D rcv_flags;
>  	if (SCTP_BUF_IS_EXTENDED(sp->data)) {
>  		chk->copy_by_ref =3D 1;

Pointy hat to rrs@.

> --- src/usr.sbin/nscd/agents/services.c~	2007-08-14 15:44:33.000000000 -0=
400
> +++ src/usr.sbin/nscd/agents/services.c	2007-08-14 15:44:41.000000000 -04=
00
> @@ -171,7 +171,7 @@ services_lookup_func(const char *key, si
>  		if (size > 0) {
>  			proto =3D (char *)malloc(size + 1);
>  			assert(proto !=3D NULL);
> -			memset(proto, size + 1, 0);
> +			memset(proto, 0, size + 1);
>  			memcpy(proto, key + sizeof(enum nss_lookup_type) +
>  				sizeof(int), size);
>  		}
> --- src/usr.sbin/cached/agents/services.c~	2007-08-14 15:44:45.000000000 =
-0400
> +++ src/usr.sbin/cached/agents/services.c	2007-08-14 15:44:52.000000000 -=
0400
> @@ -171,7 +171,7 @@ services_lookup_func(const char *key, si
>  		if (size > 0) {
>  			proto =3D (char *)malloc(size + 1);
>  			assert(proto !=3D NULL);
> -			memset(proto, size + 1, 0);
> +			memset(proto, 0, size + 1);
>  			memcpy(proto, key + sizeof(enum nss_lookup_type) +
>  				sizeof(int), size);
>  		}

These two are actually the same file - cached is in the process of being
renamed to nscd.  Pointy hat to bushman@.

> --- src/contrib/gdb/gdb/std-regs.c~	2007-08-14 15:44:56.000000000 -0400
> +++ src/contrib/gdb/gdb/std-regs.c	2007-08-14 15:45:22.000000000 -0400
> @@ -61,7 +61,7 @@ value_of_builtin_frame_reg (struct frame
>    val =3D allocate_value (builtin_type_frame_reg);
>    VALUE_LVAL (val) =3D not_lval;
>    buf =3D VALUE_CONTENTS_RAW (val);
> -  memset (buf, TYPE_LENGTH (VALUE_TYPE (val)), 0);
> +  memset (buf, 0, TYPE_LENGTH (VALUE_TYPE (val)));
>    /* frame.base.  */
>    if (frame !=3D NULL)
>      ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
> @@ -87,7 +87,7 @@ value_of_builtin_frame_fp_reg (struct fr
>        struct value *val =3D allocate_value (builtin_type_void_data_ptr);
>        char *buf =3D VALUE_CONTENTS_RAW (val);
>        if (frame =3D=3D NULL)
> -	memset (buf, TYPE_LENGTH (VALUE_TYPE (val)), 0);
> +	memset (buf, 0, TYPE_LENGTH (VALUE_TYPE (val)));
>        else
>  	ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
>  			    get_frame_base_address (frame));
> @@ -105,7 +105,7 @@ value_of_builtin_frame_pc_reg (struct fr
>        struct value *val =3D allocate_value (builtin_type_void_data_ptr);
>        char *buf =3D VALUE_CONTENTS_RAW (val);
>        if (frame =3D=3D NULL)
> -	memset (buf, TYPE_LENGTH (VALUE_TYPE (val)), 0);
> +	memset (buf, 0, TYPE_LENGTH (VALUE_TYPE (val)));
>        else
>  	ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
>  			    get_frame_pc (frame));
> --- src/contrib/gdb/gdb/remote.c~	2007-08-14 15:45:25.000000000 -0400
> +++ src/contrib/gdb/gdb/remote.c	2007-08-14 15:45:37.000000000 -0400
> @@ -3463,7 +3463,7 @@ remote_store_registers (int regnum)
>    {
>      int i;
>      regs =3D alloca (rs->sizeof_g_packet);
> -    memset (regs, rs->sizeof_g_packet, 0);
> +    memset (regs, 0, rs->sizeof_g_packet);
>      for (i =3D 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
>        {
>  	struct packet_reg *r =3D &rs->regs[i];

These should go upstream to the gdb maintainers (bug-gdb@gnu.org).

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no
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