diff mbox series

[ovs-dev,V2,6/8] netlink: Fix writing bytes into a region of size 0 overflows the destination

Message ID 20221116104727.915151-7-elibr@nvidia.com
State Deferred
Headers show
Series Fix warnings and enable Werror | expand

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Commit Message

Eli Britstein Nov. 16, 2022, 10:47 a.m. UTC 
With --enable-Werror and --with-dpdk=no, with gcc (Ubuntu 11.2.0-19ubuntu1),
there are the following warnings (errors) emmitted. Those are reported
in [1] to be GCC bug. Workaround it.

In function 'memset',
    inlined from 'nl_msg_put_uninit' at ../lib/netlink.c:212:9,
    inlined from 'nl_msg_put_unspec_uninit' at ../lib/netlink.c:248:26,
    inlined from 'nl_msg_put_unspec' at ../lib/netlink.c:276:11,
    inlined from 'nl_msg_put_u8' at ../lib/netlink.c:294:5:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:59:10: error: '__builtin_memset' writing 3 bytes into a region of size 0 overflows the destination [-Werror=stringop-overflow=]
   59 |   return __builtin___memset_chk (__dest, __ch, __len,
      |          ^
In function 'memset',
    inlined from 'nl_msg_put_uninit' at ../lib/netlink.c:212:9,
    inlined from 'nl_msg_put_unspec_uninit' at ../lib/netlink.c:248:26,
    inlined from 'nl_msg_put_unspec' at ../lib/netlink.c:276:11,
    inlined from 'nl_msg_put_u16' at ../lib/netlink.c:302:5:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:59:10: error: '__builtin_memset' writing 2 bytes into a region of size 0 overflows the destination [-Werror=stringop-overflow=]
   59 |   return __builtin___memset_chk (__dest, __ch, __len,
      |          ^

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92718

Signed-off-by: Eli Britstein <elibr@nvidia.com>
---
 lib/netlink.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/lib/netlink.c b/lib/netlink.c
index 6215282d6..c30620fdb 100644
--- a/lib/netlink.c
+++ b/lib/netlink.c
@@ -200,6 +200,14 @@  nl_msg_put(struct ofpbuf *msg, const void *data, size_t size)
     memcpy(nl_msg_put_uninit(msg, size), data, size);
 }
 
+static void
+nl_msg_zero_pad(char *pad_ptr, size_t pad_size)
+{
+    while (pad_size--) {
+        *pad_ptr++ = 0;
+    }
+}
+
 /* Appends 'size' bytes of data, plus Netlink padding if needed, to the tail
  * end of 'msg', reallocating and copying its data if necessary.  Returns a
  * pointer to the first byte of the new data, which is left uninitialized. */
@@ -208,9 +216,7 @@  nl_msg_put_uninit(struct ofpbuf *msg, size_t size)
 {
     size_t pad = PAD_SIZE(size, NLMSG_ALIGNTO);
     char *p = ofpbuf_put_uninit(msg, size + pad);
-    if (pad) {
-        memset(p + size, 0, pad);
-    }
+    nl_msg_zero_pad(p + size, pad);
     return p;
 }
 
@@ -231,9 +237,7 @@  nl_msg_push_uninit(struct ofpbuf *msg, size_t size)
 {
     size_t pad = PAD_SIZE(size, NLMSG_ALIGNTO);
     char *p = ofpbuf_push_uninit(msg, size + pad);
-    if (pad) {
-        memset(p + size, 0, pad);
-    }
+    nl_msg_zero_pad(p + size, pad);
     return p;
 }