When doing multi-part formposts, libcurl used a pseudo-random value that
was seeded with time(). This turns out to be bad for users who formpost
data that is provided with users who then can guess how the boundary
string will look like and then they can forge a different formpost part
and trick the receiver.
My advice to such implementors is (still even after this change) to not
rely on the boundary strings being cryptographically strong. Fix your
code and logic to not depend on them that much!
I moved the Curl_rand() function into the sslgen.c source file now to be
able to take advantage of the SSL library's random function if it
provides one. If not, try to use the RANDOM_FILE for seeding and as a
last resort keep the old logic, just modified to also add microseconds
which makes it harder to properly guess the exact seed.
The formboundary() function in formdata.c is now using 64 bit entropy
for the boundary and therefore the string of dashes was reduced by 4
letters and there are 16 hex digits following it. The total length is
thus still the same.
Bug: http://curl.haxx.se/bug/view.cgi?id=1251
Reported-by: "Floris"
A regression where CURLFORM_BUFFER stopped to properly insert the file
name part in the formpart. Bug introduced in commit f851f76857.
Added CURLFORM_BUFFER use to test 554 to verify this.
Bug: http://curl.haxx.se/mail/lib-2011-07/0176.html
Reported by: Henry Ludemann
The CURLFORM_STREAM is documented to only insert a file name (and thus
look like a file upload) in the part if CURLFORM_FILENAME is set, but in
reality it always inserted a filename="" and if CURLFORM_FILENAME wasn't
set, it would insert insert rubbish (or possibly crash).
This is now fixed to work as documented, and test 554 has been extended
to verify this.
Reported by: Sascha Swiercy
Bug: http://curl.haxx.se/mail/lib-2011-06/0070.html
application to provide data for a multipart with the read callback. Note
that the size needs to be provided with CURLFORM_CONTENTSLENGTH when the
stream option is used. This feature is verified by the new test case
554. This feature was sponsored by Xponaut.
