In 948fa3b ("Extend accounting capabilities to support quotas"), the
error handling of snprintf is incorrect since this function may
return -1 on error. Add a new SNPRINTF_CHECK() macro to offload the
complicated handling of snprintf.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
src/internal.h | 11 +++++++++++
src/libnetfilter_acct.c | 21 ++++++++-------------
2 files changed, 19 insertions(+), 13 deletions(-)
diff --git a/src/internal.h b/src/internal.h
index 2106401..f0cc2e1 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -21,4 +21,15 @@
# endif
#endif
+#define SNPRINTF_CHECK(ret, rem, offset, len) \
+do { \
+ if (ret < 0) \
+ return ret; \
+ len += ret; \
+ if (ret > rem) \
+ ret = rem; \
+ offset += ret; \
+ rem -= ret; \
+} while (0)
+
#endif
diff --git a/src/libnetfilter_acct.c b/src/libnetfilter_acct.c
index 0c1a758..7f539b6 100644
--- a/src/libnetfilter_acct.c
+++ b/src/libnetfilter_acct.c
@@ -256,42 +256,37 @@ static int
nfacct_snprintf_plain(char *buf, size_t rem, struct nfacct *nfacct,
uint16_t flags)
{
- int ret, temp;
- char *walking_buf;
-
- temp = rem;
- walking_buf = buf;
+ int ret, offset = 0, len = 0;
if (flags & NFACCT_SNPRINTF_F_FULL) {
- ret = snprintf(walking_buf, temp,
+ ret = snprintf(buf, rem,
"{ pkts = %.20"PRIu64", bytes = %.20"PRIu64"",
nfacct_attr_get_u64(nfacct, NFACCT_ATTR_PKTS),
nfacct_attr_get_u64(nfacct, NFACCT_ATTR_BYTES));
+ SNPRINTF_CHECK(ret, rem, offset, len);
if (nfacct->flags) {
uint32_t mode;
mode = nfacct_attr_get_u64(nfacct, NFACCT_ATTR_FLAGS);
- walking_buf += ret;
- temp -= ret;
- ret = snprintf(walking_buf, temp,
+ ret = snprintf(buf + offset, rem,
", quota = %.20"PRIu64", mode = %s",
nfacct_attr_get_u64(nfacct, NFACCT_ATTR_QUOTA),
mode == NFACCT_F_QUOTA_BYTES ?
"byte" : "packet");
+ SNPRINTF_CHECK(ret, rem, offset, len);
}
- walking_buf += ret;
- temp -= ret;
- ret = snprintf(walking_buf, temp, " } = %s;",
+ ret = snprintf(buf + offset, rem, " } = %s;",
nfacct_attr_get_str(nfacct, NFACCT_ATTR_NAME));
} else {
ret = snprintf(buf, rem, "%s\n",
nfacct_attr_get_str(nfacct, NFACCT_ATTR_NAME));
}
+ SNPRINTF_CHECK(ret, rem, offset, len);
- return ret;
+ return len;
}
#define BUFFER_SIZE(ret, size, rem, offset) \
--
1.7.10.4
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
