Re: [PATCH] nss: Get rid of alloca usage in db-XXX

[Andreas Schwab <schwab@suse.de>]

On Sep 27 2023, Joe Simmons-Talbott wrote:

> Replace alloca usage with a scratch_buffer.
> ---
>  nss/nss_db/db-XXX.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/nss/nss_db/db-XXX.c b/nss/nss_db/db-XXX.c
> index 0ce730db5a..2df31a8077 100644
> --- a/nss/nss_db/db-XXX.c
> +++ b/nss/nss_db/db-XXX.c
> @@ -18,6 +18,7 @@
>  
>  #include <dlfcn.h>
>  #include <fcntl.h>
> +#include <scratch_buffer.h>
>  #include <stdint.h>
>  #include <sys/mman.h>
>  #include <libc-lock.h>
> @@ -126,6 +127,8 @@ enum nss_status								      \
>  			char *buffer, size_t buflen, int *errnop H_ERRNO_PROTO)\
>  {									      \
>    struct parser_data *data = (void *) buffer;				      \
> +  struct scratch_buffer sbuf;						      \
> +  scratch_buffer_init (&sbuf);						      \
>  									      \
>    if (buflen < sizeof *data)						      \
>      {									      \
> @@ -160,7 +163,13 @@ enum nss_status								      \
>    else									      \
>      {									      \
>        const size_t size = (keysize) + 1;				      \
> -      key = alloca (size);						      \
> +      if (!scratch_buffer_set_array_size (&sbuf, 1, size))		      \
> +	{								      \
> +	  H_ERRNO_SET (NETDB_INTERNAL);					      \
> +	  status = NSS_STATUS_TRYAGAIN;					      \
> +	  return status;						      \

That needs to set *errnop and goto out.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
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