From: Steffan Karger <steffan.kar...@fox-it.com>
By using get_random() instead of prng_bytes(), we no longer have to place
create_temp_file() inside #ifdef ENABLE_CRYPTO.
The resulting filename now has 62 bits of entropy (2 * [0-INT_MAX])
instead of the previous 128 bits, but that should be plenty. Assuming an
int is 32 bits, we would need about 2**31 (2147483648) files to have a
(roughly) 0.5 chance of failing in one of the 6 attempts we do.
(This is preparing to move the function out of misc.c, where I'd prefer to
not have to add a #include "crypto.h".)
Signed-off-by: Steffan Karger <steffan.kar...@fox-it.com>
---
src/openvpn/misc.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/src/openvpn/misc.c b/src/openvpn/misc.c
index 4f729911..1537a2e4 100644
--- a/src/openvpn/misc.c
+++ b/src/openvpn/misc.c
@@ -831,8 +831,6 @@ test_file(const char *filename)
return ret;
}
-#ifdef ENABLE_CRYPTO
-
/* create a temporary filename in directory */
const char *
create_temp_file(const char *directory, const char *prefix, struct gc_arena
*gc)
@@ -845,15 +843,11 @@ create_temp_file(const char *directory, const char
*prefix, struct gc_arena *gc)
do
{
- uint8_t rndbytes[16];
- const char *rndstr;
-
++attempts;
++counter;
- prng_bytes(rndbytes, sizeof rndbytes);
- rndstr = format_hex_ex(rndbytes, sizeof rndbytes, 40, 0, NULL, gc);
- buf_printf(&fname, PACKAGE "_%s_%s.tmp", prefix, rndstr);
+ buf_printf(&fname, PACKAGE "_%s_%08lx%08lx.tmp", prefix,
+ (unsigned long) get_random(), (unsigned long) get_random());
retfname = gen_path(directory, BSTR(&fname), gc);
if (!retfname)
@@ -884,6 +878,8 @@ create_temp_file(const char *directory, const char *prefix,
struct gc_arena *gc)
return NULL;
}
+#ifdef ENABLE_CRYPTO
+
/*
* Prepend a random string to hostname to prevent DNS caching.
* For example, foo.bar.gov would be modified to <random-chars>.foo.bar.gov.
--
2.11.0
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