Em seg., 2 de mar. de 2020 às 17:13, Julio Faracco
<jcfara...@gmail.com> escreveu:
>
> When HAX is enabled (--enable-hax), GCC 9.2.1 reports issues with
> snprintf(). Replacing old snprintf() by g_strdup_printf() fixes the
> problem with boundary checks of vm_id and vcpu_id and finally the
> warnings produced by GCC.
>
> For more details, one example of warning:
> CC i386-softmmu/target/i386/hax-posix.o
> qemu/target/i386/hax-posix.c: In function ‘hax_host_open_vm’:
> qemu/target/i386/hax-posix.c:124:56: error: ‘%02d’ directive output may be
> truncated writing between 2 and 11 bytes into a region of size 3
> [-Werror=format-truncation=]
> 124 | snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> | ^~~~
> qemu/target/i386/hax-posix.c:124:41: note: directive argument in the range
> [-2147483648, 64]
> 124 | snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> | ^~~~~~~~~~~~~~~~~~~~
> In file included from /usr/include/stdio.h:867,
> from qemu/include/qemu/osdep.h:99,
> from qemu/target/i386/hax-posix.c:14:
> /usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output
> between 17 and 26 bytes into a destination of size 17
> 67 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 68 | __bos (__s), __fmt, __va_arg_pack ());
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Signed-off-by: Julio Faracco <jcfara...@gmail.com>
> ---
> v1-v2: Add assert() as Richard Henderson suggested.
> v2-v3: Fix code syntax alignment with vm_id and snprintf() function.
> v3-v4: Replacing snprintf() by g_strdup_printf() from linux and windows.
> ---
> ---
> target/i386/hax-posix.c | 33 ++-------------------------------
> target/i386/hax-windows.c | 33 ++-------------------------------
> 2 files changed, 4 insertions(+), 62 deletions(-)
>
> diff --git a/target/i386/hax-posix.c b/target/i386/hax-posix.c
> index a5426a6dac..3bad89f133 100644
> --- a/target/i386/hax-posix.c
> +++ b/target/i386/hax-posix.c
> @@ -108,41 +108,12 @@ int hax_mod_version(struct hax_state *hax, struct
> hax_module_version *version)
>
> static char *hax_vm_devfs_string(int vm_id)
> {
> - char *name;
> -
> - if (vm_id > MAX_VM_ID) {
> - fprintf(stderr, "Too big VM id\n");
> - return NULL;
> - }
> -
> -#define HAX_VM_DEVFS "/dev/hax_vm/vmxx"
> - name = g_strdup(HAX_VM_DEVFS);
> - if (!name) {
> - return NULL;
> - }
> -
> - snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> - return name;
> + return g_strdup_printf("/dev/hax_vm/vm%02d", vm_id);
> }
>
> static char *hax_vcpu_devfs_string(int vm_id, int vcpu_id)
> {
> - char *name;
> -
> - if (vm_id > MAX_VM_ID || vcpu_id > MAX_VCPU_ID) {
> - fprintf(stderr, "Too big vm id %x or vcpu id %x\n", vm_id, vcpu_id);
> - return NULL;
> - }
We probably need a V5 to remove definitions from hax-i386.h:
#define MAX_VM_ID 0x40
#define MAX_VCPU_ID 0x40
That's why I asked about IF last patch. ;-)
> -
> -#define HAX_VCPU_DEVFS "/dev/hax_vmxx/vcpuxx"
> - name = g_strdup(HAX_VCPU_DEVFS);
> - if (!name) {
> - return NULL;
> - }
> -
> - snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
> - vm_id, vcpu_id);
> - return name;
> + return g_strdup_printf("/dev/hax_vm%02d/vcpu%02d", vm_id, vcpu_id);
> }
>
> int hax_host_create_vm(struct hax_state *hax, int *vmid)
> diff --git a/target/i386/hax-windows.c b/target/i386/hax-windows.c
> index 5729ad9b48..0ba488c468 100644
> --- a/target/i386/hax-windows.c
> +++ b/target/i386/hax-windows.c
> @@ -185,41 +185,12 @@ int hax_mod_version(struct hax_state *hax, struct
> hax_module_version *version)
>
> static char *hax_vm_devfs_string(int vm_id)
> {
> - char *name;
> -
> - if (vm_id > MAX_VM_ID) {
> - fprintf(stderr, "Too big VM id\n");
> - return NULL;
> - }
> -
> -#define HAX_VM_DEVFS "\\\\.\\hax_vmxx"
> - name = g_strdup(HAX_VM_DEVFS);
> - if (!name) {
> - return NULL;
> - }
> -
> - snprintf(name, sizeof HAX_VM_DEVFS, "\\\\.\\hax_vm%02d", vm_id);
> - return name;
> + return g_strdup_printf("/dev/hax_vm/vm%02d", vm_id);
> }
>
> static char *hax_vcpu_devfs_string(int vm_id, int vcpu_id)
> {
> - char *name;
> -
> - if (vm_id > MAX_VM_ID || vcpu_id > MAX_VCPU_ID) {
> - fprintf(stderr, "Too big vm id %x or vcpu id %x\n", vm_id, vcpu_id);
> - return NULL;
> - }
> -
> -#define HAX_VCPU_DEVFS "\\\\.\\hax_vmxx_vcpuxx"
> - name = g_strdup(HAX_VCPU_DEVFS);
> - if (!name) {
> - return NULL;
> - }
> -
> - snprintf(name, sizeof HAX_VCPU_DEVFS, "\\\\.\\hax_vm%02d_vcpu%02d",
> - vm_id, vcpu_id);
> - return name;
> + return g_strdup_printf("/dev/hax_vm%02d/vcpu%02d", vm_id, vcpu_id);
> }
>
> int hax_host_create_vm(struct hax_state *hax, int *vmid)
> --
> 2.24.1
>
