From: Jakub Kicinski <jakub.kicin...@netronome.com> Date: Tue, 17 Jul 2018 14:32:24 -0700
> GCC 8 complains: > > net/core/pktgen.c: In function ‘pktgen_if_write’: > net/core/pktgen.c:1419:4: warning: ‘strncpy’ output may be truncated copying > between 0 and 31 bytes from a string of length 127 [-Wstringop-truncation] > strncpy(pkt_dev->src_max, buf, len); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > net/core/pktgen.c:1399:4: warning: ‘strncpy’ output may be truncated copying > between 0 and 31 bytes from a string of length 127 [-Wstringop-truncation] > strncpy(pkt_dev->src_min, buf, len); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > net/core/pktgen.c:1290:4: warning: ‘strncpy’ output may be truncated copying > between 0 and 31 bytes from a string of length 127 [-Wstringop-truncation] > strncpy(pkt_dev->dst_max, buf, len); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > net/core/pktgen.c:1268:4: warning: ‘strncpy’ output may be truncated copying > between 0 and 31 bytes from a string of length 127 [-Wstringop-truncation] > strncpy(pkt_dev->dst_min, buf, len); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > There is no bug here, but the code is not perfect either. It copies > sizeof(pkt_dev->/member/) - 1 from user space into buf, and then does > a strcmp(pkt_dev->/member/, buf) hence assuming buf will be null-terminated > and shorter than pkt_dev->/member/ (pkt_dev->/member/ is never > explicitly null-terminated, and strncpy() doesn't have to null-terminate > so the assumption must be on buf). The use of strncpy() without explicit > null-termination looks suspicious. Convert to use straight strcpy(). > > strncpy() would also null-pad the output, but that's clearly unnecessary > since the author calls memset(pkt_dev->/member/, 0, sizeof(..)); prior > to strncpy(), anyway. > > While at it format the code for "dst_min", "dst_max", "src_min" and > "src_max" in the same way by removing extra new lines in one case. > > Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com> > Reviewed-by: Jiong Wang <jiong.w...@netronome.com> Applied, thanks Jakub.
