On Wed, May 01, 2019 at 11:40:13AM +0200, Laurent Vivier wrote: > On 01/05/2019 01:28, Alistair Francis wrote: > > Fix this warning when building with GCC9 on Fedora 30: > > In function ‘strncpy’, > > inlined from ‘sys_uname’ at /home/alistair/qemu/linux-user/uname.c:94:3: > > /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ > > output may be truncated copying 64 bytes from a string of length 64 > > [-Werror=stringop-truncation] > > 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos > > (__dest)); > > | > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > Signed-off-by: Alistair Francis <alistair.fran...@wdc.com> > > --- > > linux-user/uname.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/linux-user/uname.c b/linux-user/uname.c > > index 313b79dbad..2fc6096a5b 100644 > > --- a/linux-user/uname.c > > +++ b/linux-user/uname.c > > @@ -73,7 +73,7 @@ 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); \ > > + (void) memcpy((dest), (src), MIN(strlen(src), __NEW_UTS_LEN)); \ > > You should use MIN(strlen(src) + 1, __NEW_UTS_LEN) to copy the NUL > character if it is present and fit in __NEW_UTS_LEN.
IMHO we shouldn't use strlen at all. I proposed fixing it using sizeof() instead here: https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg02154.html > > > (dest)[__NEW_UTS_LEN] = '\0'; \ > > } while (0) Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|