Paolo Bonzini <pbonz...@redhat.com> writes:
> This is the model file that is being used for the QEMU project's scans
> on scan.coverity.com. It fixed about 30 false positives (10% of the
> total) and exposed about 60 new memory leaks.
>
> The file is not automatically used; changes to it must be propagated
> to the website manually by an admin (right now Markus, Peter and me
> are admins).
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> scripts/coverity-model.c | 170
> +++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 170 insertions(+)
> create mode 100644 scripts/coverity-model.c
>
> diff --git a/scripts/coverity-model.c b/scripts/coverity-model.c
> new file mode 100644
> index 0000000..1cc0c1b
> --- /dev/null
> +++ b/scripts/coverity-model.c
> @@ -0,0 +1,170 @@
> +/* Coverity Scan model
> + *
> + * Copyright (C) 2014 Red Hat, Inc.
> + *
> + * Authors:
> + * Markus Armbruster <arm...@redhat.com>
> + * Paolo Bonzini <pbonz...@redhat.com>
> + *
> + * This is a modeling file for Coverity Scan. Modeling helps to avoid false
> + * positives.
> + *
> + * - A model file can't import any header files. Some built-in primitives
> are
> + * available but not wchar_t, NULL etc.
> + * - Modeling doesn't need full structs and typedefs. Rudimentary structs
> + * and similar types are sufficient.
> + * - An uninitialized local variable signifies that the variable could be
> + * any value.
> + *
> + * The model file must be uploaded by an admin in the analysis settings of
> + * http://scan.coverity.com/projects/378
> + */
> +
> +#define NULL (void *)0
> +#define assert(x) if (!(x)) __coverity_panic__();
> +
> +typedef unsigned char uint8_t;
> +typedef char int8_t;
> +typedef unsigned int uint32_t;
> +typedef int int32_t;
> +typedef long ssize_t;
> +typedef unsigned long long uint64_t;
> +typedef long long int64_t;
> +typedef _Bool bool;
> +
> +/* exec.c */
> +
> +typedef struct AddressSpace AddressSpace;
> +typedef uint64_t hwaddr;
> +
> +static void __write(uint8_t *buf, int len)
> +{
> + int first, last;
> + __coverity_negative_sink__(len);
> + if (len == 0) return;
> + buf[0] = first;
> + buf[len-1] = last;
> + __coverity_writeall__(buf);
> +}
> +
> +static void __read(uint8_t *buf, int len)
> +{
> + __coverity_negative_sink__(len);
> + if (len == 0) return;
> + int first = buf[0];
> + int last = buf[len-1];
> +}
> +
> +bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
> + int len, bool is_write)
> +{
> + bool result;
> +
> + // perhaps __coverity_tainted_data_argument__(buf); for read,
> + // and __coverity_tainted_data_sink__(buf); for write?
> + if (is_write) __write(buf, len); else __read(buf, len);
> +
> + return result;
> +}
> +
> +/* Tainting */
> +
> +typedef struct {} name2keysym_t;
> +static int get_keysym(const name2keysym_t *table,
> + const char *name)
> +{
> + int result;
> + if (result > 0) {
> + __coverity_tainted_string_sanitize_content__(name);
> + return result;
> + } else {
> + return 0;
> + }
> +}
> +
> +/* glib */
> +
> +void *malloc (size_t);
> +void *calloc (size_t, size_t);
> +void *realloc (void *, size_t);
> +void free (void *);
> +
> +void *
> +g_malloc (size_t n_bytes)
> +{
> + void *mem;
> + __coverity_negative_sink__((ssize_t) n_bytes);
> + mem = malloc(n_bytes == 0 ? 1 : n_bytes);
> + if (!mem) __coverity_panic__ ();
> + return mem;
> +}
This isn't quite honest: g_malloc(0) yields NULL. Same for the other
allocation functions.
> +
> +void *
> +g_malloc0 (size_t n_bytes)
> +{
> + void *mem;
> + __coverity_negative_sink__((ssize_t) n_bytes);
> + mem = calloc(1, n_bytes == 0 ? 1 : n_bytes);
> + if (!mem) __coverity_panic__ ();
> + return mem;
> +}
> +
> +void g_free (void *mem)
> +{
> + if (mem) {
> + free(mem);
> + }
> +}
Unconditional free(mem) should be fine.
> +
> +void *g_realloc (void * mem, size_t n_bytes)
> +{
> + __coverity_negative_sink__((ssize_t) n_bytes);
> + if (n_bytes == 0) {
> + g_free(mem);
> + return NULL;
> + } else {
> + mem = realloc(mem, n_bytes);
> + if (!mem) __coverity_panic__ ();
> + return mem;
> + }
> +}
> +
> +void *g_try_malloc (size_t n_bytes)
> +{
> + __coverity_negative_sink__((ssize_t) n_bytes);
> + return malloc(n_bytes == 0 ? 1 : n_bytes);
> +}
> +
> +void *g_try_malloc0 (size_t n_bytes)
> +{
> + __coverity_negative_sink__((ssize_t) n_bytes);
> + return calloc(1, n_bytes == 0 ? 1 : n_bytes);
> +}
> +
> +void *g_try_realloc (void *mem, size_t n_bytes)
> +{
> + __coverity_negative_sink__((ssize_t) n_bytes);
> + if (n_bytes == 0) {
> + g_free(mem);
> + return NULL;
> + } else {
> + return realloc(mem, n_bytes);
> + }
> +}
> +
> +typedef struct _GIOChannel GIOChannel;
> +GIOChannel *g_io_channel_unix_new(int fd)
> +{
> + GIOChannel *c = g_malloc0(sizeof(GIOChannel));
> + __coverity_escape__(fd);
> + return c;
> +}
> +
> +void g_assertion_message_expr(const char *domain,
> + const char *file,
> + int line,
> + const char *func,
> + const char *expr)
> +{
> + __coverity_panic__();
> +}
I wonder how much scanning power a derived model for GLib adds. I'll
find out.
