* [PATCH] libiptc.c: pragma disable a gcc compiler warning
@ 2020-05-11 21:34 Maciej Żenczykowski
2020-05-14 17:58 ` Pablo Neira Ayuso
0 siblings, 1 reply; 2+ messages in thread
From: Maciej Żenczykowski @ 2020-05-11 21:34 UTC (permalink / raw)
To: Maciej Żenczykowski, Pablo Neira Ayuso, Florian Westphal
Cc: Linux Network Development Mailing List,
Netfilter Development Mailing List
From: Maciej Żenczykowski <maze@google.com>
Fixes:
In file included from libip4tc.c:113:
In function ‘iptcc_compile_chain’,
inlined from ‘iptcc_compile_table’ at libiptc.c:1246:13,
inlined from ‘iptc_commit’ at libiptc.c:2575:8,
inlined from ‘iptc_commit’ at libiptc.c:2513:1:
libiptc.c:1172:2: warning: writing 16 bytes into a region of size 0 [-Wstringop-overflow=]
1172 | memcpy(&foot->e.counters, &c->counters, sizeof(STRUCT_COUNTERS));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../include/libiptc/libiptc.h:12,
from libip4tc.c:29:
libiptc.c: In function ‘iptc_commit’:
../include/linux/netfilter_ipv4/ip_tables.h:202:19: note: at offset 0 to object ‘entries’ with size 0 declared here
202 | struct ipt_entry entries[0];
| ^~~~~~~
Which was found via compilation on Fedora 32.
Test: builds without warnings
Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
libiptc/libiptc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/libiptc/libiptc.c b/libiptc/libiptc.c
index 58882015..1a92b267 100644
--- a/libiptc/libiptc.c
+++ b/libiptc/libiptc.c
@@ -1169,7 +1169,10 @@ static int iptcc_compile_chain(struct xtc_handle *h, STRUCT_REPLACE *repl, struc
else
foot->target.verdict = RETURN;
/* set policy-counters */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
memcpy(&foot->e.counters, &c->counters, sizeof(STRUCT_COUNTERS));
+#pragma GCC diagnostic pop
return 0;
}
--
2.26.2.645.ge9eca65c58-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] libiptc.c: pragma disable a gcc compiler warning
2020-05-11 21:34 [PATCH] libiptc.c: pragma disable a gcc compiler warning Maciej Żenczykowski
@ 2020-05-14 17:58 ` Pablo Neira Ayuso
0 siblings, 0 replies; 2+ messages in thread
From: Pablo Neira Ayuso @ 2020-05-14 17:58 UTC (permalink / raw)
To: Maciej Żenczykowski
Cc: Maciej Żenczykowski, Florian Westphal,
Linux Network Development Mailing List,
Netfilter Development Mailing List
On Mon, May 11, 2020 at 02:34:04PM -0700, Maciej Żenczykowski wrote:
> From: Maciej Żenczykowski <maze@google.com>
>
> Fixes:
> In file included from libip4tc.c:113:
> In function ‘iptcc_compile_chain’,
> inlined from ‘iptcc_compile_table’ at libiptc.c:1246:13,
> inlined from ‘iptc_commit’ at libiptc.c:2575:8,
> inlined from ‘iptc_commit’ at libiptc.c:2513:1:
> libiptc.c:1172:2: warning: writing 16 bytes into a region of size 0 [-Wstringop-overflow=]
> 1172 | memcpy(&foot->e.counters, &c->counters, sizeof(STRUCT_COUNTERS));
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> In file included from ../include/libiptc/libiptc.h:12,
> from libip4tc.c:29:
> libiptc.c: In function ‘iptc_commit’:
> ../include/linux/netfilter_ipv4/ip_tables.h:202:19: note: at offset 0 to object ‘entries’ with size 0 declared here
> 202 | struct ipt_entry entries[0];
> | ^~~~~~~
>
> Which was found via compilation on Fedora 32.
>
> Test: builds without warnings
> Signed-off-by: Maciej Żenczykowski <maze@google.com>
> ---
> libiptc/libiptc.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/libiptc/libiptc.c b/libiptc/libiptc.c
> index 58882015..1a92b267 100644
> --- a/libiptc/libiptc.c
> +++ b/libiptc/libiptc.c
> @@ -1169,7 +1169,10 @@ static int iptcc_compile_chain(struct xtc_handle *h, STRUCT_REPLACE *repl, struc
> else
> foot->target.verdict = RETURN;
> /* set policy-counters */
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Wstringop-overflow"
> memcpy(&foot->e.counters, &c->counters, sizeof(STRUCT_COUNTERS));
> +#pragma GCC diagnostic pop
Probably make a casting from foot->e.counters to the counters object
to make gcc happy?
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