| Message ID | 20181120152753.10463-2-marcandre.lureau@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | strcpy: fix stringop-truncation warnings | expand |
On 11/20/18 9:27 AM, Marc-André Lureau wrote: > It seems adding an assert is enough to silence GCC. > (sd_parse_snapid_or_tag() g_strlcpy() ensures that we don't get in > that situation) > > ~/src/qemu/block/sheepdog.c: In function 'find_vdi_name': > ~/src/qemu/block/sheepdog.c:1239:5: error: 'strncpy' specified bound 256 equals destination size [-Werror=stringop-truncation] > strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > block/sheepdog.c | 1 + > 1 file changed, 1 insertion(+) Reviewed-by: Eric Blake <eblake@redhat.com> and safe for 3.1 in my opinion
On 20/11/18 16:27, Marc-André Lureau wrote: > It seems adding an assert is enough to silence GCC. > (sd_parse_snapid_or_tag() g_strlcpy() ensures that we don't get in > that situation) > > ~/src/qemu/block/sheepdog.c: In function 'find_vdi_name': > ~/src/qemu/block/sheepdog.c:1239:5: error: 'strncpy' specified bound 256 equals destination size [-Werror=stringop-truncation] > strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors > Fixes: https://bugs.launchpad.net/bugs/1803872 > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > block/sheepdog.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/block/sheepdog.c b/block/sheepdog.c > index 0125df9d49..f8877b611d 100644 > --- a/block/sheepdog.c > +++ b/block/sheepdog.c > @@ -1236,6 +1236,7 @@ static int find_vdi_name(BDRVSheepdogState *s, const char *filename, > * don't want the send_req to read uninitialized data. > */ > strncpy(buf, filename, SD_MAX_VDI_LEN); > + assert(strlen(tag) < SD_MAX_VDI_TAG_LEN); > strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); > > memset(&hdr, 0, sizeof(hdr)); > I tried to fix this warning this way: - char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN]; + struct { + char vdi[SD_MAX_VDI_LEN]; + char vdi_tag[SD_MAX_VDI_TAG_LEN]; + } buf; ... - strncpy(buf, filename, SD_MAX_VDI_LEN); - strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); + strncpy(buf.vdi, filename, SD_MAX_VDI_LEN); + strncpy(buf.vdi_tag, tag, SD_MAX_VDI_TAG_LEN); but your patch is simpler. Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Thanks, Phil.
diff --git a/block/sheepdog.c b/block/sheepdog.c index 0125df9d49..f8877b611d 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -1236,6 +1236,7 @@ static int find_vdi_name(BDRVSheepdogState *s, const char *filename, * don't want the send_req to read uninitialized data. */ strncpy(buf, filename, SD_MAX_VDI_LEN); + assert(strlen(tag) < SD_MAX_VDI_TAG_LEN); strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); memset(&hdr, 0, sizeof(hdr));
It seems adding an assert is enough to silence GCC. (sd_parse_snapid_or_tag() g_strlcpy() ensures that we don't get in that situation) ~/src/qemu/block/sheepdog.c: In function 'find_vdi_name': ~/src/qemu/block/sheepdog.c:1239:5: error: 'strncpy' specified bound 256 equals destination size [-Werror=stringop-truncation] strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> --- block/sheepdog.c | 1 + 1 file changed, 1 insertion(+)