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authorDaniel Stenberg <daniel@haxx.se>2011-09-25 17:34:12 +0200
committerDaniel Stenberg <daniel@haxx.se>2011-09-25 17:34:12 +0200
commit2d6796aac51d8a5963f552b8fa23a2396a987913 (patch)
treeb67ad0bdad0d0601b454fdf5741422319e43afd7 /docs
parentbb94b92894eef5d62d9b19b39cf5af921ee5fd2d (diff)
curl_multi_fdset: avoid FD_SET out of bounds
If a socket is larger than FD_SETSIZE, avoid using FD_SET() on the platforms where this is possible. Bug: http://curl.haxx.se/bug/view.cgi?id=3413274 Reported by: Tim Starling
Diffstat (limited to 'docs')
-rw-r--r--docs/libcurl/curl_multi_fdset.38
1 files changed, 8 insertions, 0 deletions
diff --git a/docs/libcurl/curl_multi_fdset.3 b/docs/libcurl/curl_multi_fdset.3
index fadc53812..bdb389f26 100644
--- a/docs/libcurl/curl_multi_fdset.3
+++ b/docs/libcurl/curl_multi_fdset.3
@@ -53,6 +53,14 @@ When doing select(), you should use \fBcurl_multi_timeout\fP to figure out how
long to wait for action. Call \fIcurl_multi_perform\fP even if no activity has
been seen on the fd_sets after the timeout expires as otherwise internal
retries and timeouts may not work as you'd think and want.
+
+If one of the sockets used by libcurl happens to be larger than what can be
+set in an fd_set, which on POSIX systems means that the file descriptor is
+larger than FD_SETSIZE, then libcurl will try to not set it. Setting a too
+large file descriptor in an fd_set implies an out of bounds write which can
+cause crashes, or worse. The effect of NOT storing it will possibly save you
+from the crash, but will make your program NOT wait for sockets it should wait
+for...
.SH RETURN VALUE
CURLMcode type, general libcurl multi interface error code. See
\fIlibcurl-errors(3)\fP