diff options
| author | Daniel Stenberg <daniel@haxx.se> | 2013-06-24 22:24:35 +0200 |
|---|---|---|
| committer | Daniel Stenberg <daniel@haxx.se> | 2013-06-25 09:55:49 +0200 |
| commit | 365c5ba39591fab2e60bf4f0e67d9dcf79ecc506 (patch) | |
| tree | 6e02f6904f12fcd94b1036643bc5064c809e807b /lib/gtls.h | |
| parent | cb1aa8b0e32068ec4bbbc42d41267420b46a36e7 (diff) | |
formpost: better random boundaries
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"
Diffstat (limited to 'lib/gtls.h')
| -rw-r--r-- | lib/gtls.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/lib/gtls.h b/lib/gtls.h index 84e1396b5..453542e1e 100644 --- a/lib/gtls.h +++ b/lib/gtls.h @@ -7,7 +7,7 @@ * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * - * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al. + * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms @@ -55,6 +55,10 @@ void Curl_gtls_md5sum(unsigned char *tmp, /* input */ unsigned char *md5sum, /* output */ size_t md5len); +/* this backend provides these functions: */ +#define have_curlssl_random 1 +#define have_curlssl_md5sum 1 + /* API setup for GnuTLS */ #define curlssl_init Curl_gtls_init #define curlssl_cleanup Curl_gtls_cleanup |