[RFC 8/8] ip_frag: fix gcc-12 warnings
Konstantin Ananyev
konstantin.v.ananyev at yandex.ru
Wed Jun 8 10:19:20 CEST 2022
07/06/2022 18:17, Stephen Hemminger пишет:
> The function rte_memcpy can derference past source buffer which
> will cause array out of bounds warnings. But there is no good reason
> to use rte_memcpy instead of memcpy in this code. Memcpy is just
> as fast for these small inputs, and compiler will optimize.
AFAIK, rte_memcpy() will outperform memcpy() when _size_ parameter
is a variable. Unfortunately that's exactly the case here.
So not sure it is a good change, at least without extensive perf testing.
BTW, if rte_memcpy() really access src buffer beyond it's boundaries,
I think that's definitely a bug that needs to be fixed.
>
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> ---
> lib/ip_frag/rte_ipv4_fragmentation.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/lib/ip_frag/rte_ipv4_fragmentation.c b/lib/ip_frag/rte_ipv4_fragmentation.c
> index a19f6fda6408..27a8ad224dec 100644
> --- a/lib/ip_frag/rte_ipv4_fragmentation.c
> +++ b/lib/ip_frag/rte_ipv4_fragmentation.c
> @@ -5,7 +5,6 @@
> #include <stddef.h>
> #include <errno.h>
>
> -#include <rte_memcpy.h>
> #include <rte_ether.h>
>
> #include "ip_frag_common.h"
> @@ -26,7 +25,7 @@ static inline void __fill_ipv4hdr_frag(struct rte_ipv4_hdr *dst,
> const struct rte_ipv4_hdr *src, uint16_t header_len,
> uint16_t len, uint16_t fofs, uint16_t dofs, uint32_t mf)
> {
> - rte_memcpy(dst, src, header_len);
> + memcpy(dst, src, header_len);
> fofs = (uint16_t)(fofs + (dofs >> RTE_IPV4_HDR_FO_SHIFT));
> fofs = (uint16_t)(fofs | mf << RTE_IPV4_HDR_MF_SHIFT);
> dst->fragment_offset = rte_cpu_to_be_16(fofs);
> @@ -48,7 +47,7 @@ static inline uint16_t __create_ipopt_frag_hdr(uint8_t *iph,
> struct rte_ipv4_hdr *iph_opt = (struct rte_ipv4_hdr *)ipopt_frag_hdr;
>
> ipopt_len = 0;
> - rte_memcpy(ipopt_frag_hdr, iph, sizeof(struct rte_ipv4_hdr));
> + memcpy(ipopt_frag_hdr, iph, sizeof(struct rte_ipv4_hdr));
> ipopt_frag_hdr += sizeof(struct rte_ipv4_hdr);
>
> uint8_t *p_opt = iph + sizeof(struct rte_ipv4_hdr);
> @@ -65,7 +64,7 @@ static inline uint16_t __create_ipopt_frag_hdr(uint8_t *iph,
> break;
>
> if (RTE_IPV4_HDR_OPT_COPIED(*p_opt)) {
> - rte_memcpy(ipopt_frag_hdr + ipopt_len,
> + memcpy(ipopt_frag_hdr + ipopt_len,
> p_opt, p_opt[1]);
> ipopt_len += p_opt[1];
> }
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