diff options
Diffstat (limited to 'abs/core/curl/0001-connection_check-restore-original-conn-data-after-th.patch')
-rw-r--r-- | abs/core/curl/0001-connection_check-restore-original-conn-data-after-th.patch | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/abs/core/curl/0001-connection_check-restore-original-conn-data-after-th.patch b/abs/core/curl/0001-connection_check-restore-original-conn-data-after-th.patch new file mode 100644 index 0000000..e5ed809 --- /dev/null +++ b/abs/core/curl/0001-connection_check-restore-original-conn-data-after-th.patch @@ -0,0 +1,77 @@ +From 4015fae044ce52a639c9358e22a9e948f287c89f Mon Sep 17 00:00:00 2001 +Message-Id: <4015fae044ce52a639c9358e22a9e948f287c89f.1550326608.git.jan.steffens@gmail.com> +From: Jay Satiro <raysatiro@yahoo.com> +Date: Mon, 11 Feb 2019 23:00:00 -0500 +Subject: [PATCH] connection_check: restore original conn->data after the check + +- Save the original conn->data before it's changed to the specified + data transfer for the connection check and then restore it afterwards. + +This is a follow-up to 38d8e1b 2019-02-11. + +History: + +It was discovered a month ago that before checking whether to extract a +dead connection that that connection should be associated with a "live" +transfer for the check (ie original conn->data ignored and set to the +passed in data). A fix was landed in 54b201b which did that and also +cleared conn->data after the check. The original conn->data was not +restored, so presumably it was thought that a valid conn->data was no +longer needed. + +Several days later it was discovered that a valid conn->data was needed +after the check and follow-up fix was landed in bbae24c which partially +reverted the original fix and attempted to limit the scope of when +conn->data was changed to only when pruning dead connections. In that +case conn->data was not cleared and the original conn->data not +restored. + +A month later it was discovered that the original fix was somewhat +correct; a "live" transfer is needed for the check in all cases +because original conn->data could be null which could cause a bad deref +at arbitrary points in the check. A fix was landed in 38d8e1b which +expanded the scope to all cases. conn->data was not cleared and the +original conn->data not restored. + +A day later it was discovered that not restoring the original conn->data +may lead to busy loops in applications that use the event interface, and +given this observation it's a pretty safe assumption that there is some +code path that still needs the original conn->data. This commit is the +follow-up fix for that, it restores the original conn->data after the +connection check. + +Assisted-by: tholin@users.noreply.github.com +Reported-by: tholin@users.noreply.github.com + +Fixes https://github.com/curl/curl/issues/3542 +Closes #3559 +--- + lib/url.c | 3 ++- + 1 file changed, 2 insertions(+), 1 deletion(-) + +diff --git a/lib/url.c b/lib/url.c +index bc47685db..46c8fb5fb 100644 +--- a/lib/url.c ++++ b/lib/url.c +@@ -964,8 +964,10 @@ static bool extract_if_dead(struct connectdata *conn, + /* The protocol has a special method for checking the state of the + connection. Use it to check if the connection is dead. */ + unsigned int state; ++ struct Curl_easy *olddata = conn->data; + conn->data = data; /* use this transfer for now */ + state = conn->handler->connection_check(conn, CONNCHECK_ISDEAD); ++ conn->data = olddata; + dead = (state & CONNRESULT_DEAD); + } + else { +@@ -994,7 +996,6 @@ struct prunedead { + static int call_extract_if_dead(struct connectdata *conn, void *param) + { + struct prunedead *p = (struct prunedead *)param; +- conn->data = p->data; /* transfer to use for this check */ + if(extract_if_dead(conn, p->data)) { + /* stop the iteration here, pass back the connection that was extracted */ + p->extracted = conn; +-- +2.20.1 + |