On 01/05/2019 16:46, Daniel P. Berrangé wrote:
> In file included from /usr/include/string.h:494,
> from include/qemu/osdep.h:101,
> from linux-user/uname.c:20:
> In function ‘strncpy’,
> inlined from ‘sys_uname’ at linux-user/uname.c:94:3:
> /usr/include/bits/string_fortified.h:106:10: warning: ‘__builtin_strncpy’
> output may be truncated copying 64 bytes from a string of length 64
> [-Wstringop-truncation]
> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos
> (__dest));
> |
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> We don't care where the NUL terminator in the original uname
> field was. It suffices to copy the entire original field and
> simply force a NUL terminator at the end of the new field.
>
> Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
> ---
>
> Changed in v2:
>
> - Always use sizeof() in preference to __NEW_UTS_LEN
>
> linux-user/uname.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/uname.c b/linux-user/uname.c
> index 313b79dbad..1c05f95387 100644
> --- a/linux-user/uname.c
> +++ b/linux-user/uname.c
> @@ -72,9 +72,8 @@ const char *cpu_to_uname_machine(void *cpu_env)
>
> #define COPY_UTSNAME_FIELD(dest, src) \
> do { \
> - /* __NEW_UTS_LEN doesn't include terminating null */ \
> - (void) strncpy((dest), (src), __NEW_UTS_LEN); \
> - (dest)[__NEW_UTS_LEN] = '\0'; \
> + memcpy((dest), (src), MIN(sizeof(src), sizeof(dest))); \
> + (dest)[sizeof(dest) - 1] = '\0'; \
> } while (0)
>
> int sys_uname(struct new_utsname *buf)
>
Applied to my linux-user branch.
Thanks,
Laurent
