On 5/25/2012 12:30 AM, Richard Levitte wrote:
In message<cagxgq09umap5b1bhsyjj54srwrg-syzqnodk5rh_gnt29xa...@mail.gmail.com> on
Thu, 24 May 2012 17:46:49 +0530, Sudarshan Raghavan<sudarshan.t.ragha...@gmail.com>
said:
sudarshan.t.raghavan> Hi,
sudarshan.t.raghavan>
sudarshan.t.raghavan> I am using CRYPTO_set_mem_functions to use our own
custom memory
sudarshan.t.raghavan> routines in a non blocking proxy implementation. This
was working fine
sudarshan.t.raghavan> in 0.9.8 and 1.0.0 but with 1.0.1c I can see that the
custom free
sudarshan.t.raghavan> routine is being invoked with a NULL argument after
calling SSL_free
sudarshan.t.raghavan> and this results in the proxy crashing.
sudarshan.t.raghavan>
sudarshan.t.raghavan> #3 0x0828bd24 in CUSTOM_FREE (oldMem=0x0) at
custom_mem.c:340
sudarshan.t.raghavan> #4 0xb75342b4 in CRYPTO_free () from
sudarshan.t.raghavan>
/home/product/code/firmware/current/lib/openssl1.0/lib/libcrypto.so.1.0.0
sudarshan.t.raghavan> #5 0x00000000 in ?? ()
sudarshan.t.raghavan>
sudarshan.t.raghavan> This happens every time the SSL connections is torn
down. If I don't
sudarshan.t.raghavan> use CRYPTO_set_mem_functions it works fine. I am
assuming the default
sudarshan.t.raghavan> free routine ignores a NULL argument. Is it an
expectation from the
sudarshan.t.raghavan> custom free routine to also ignore NULL? I can provide
more
sudarshan.t.raghavan> information if needed. Can someone help me debug this
problem.
sudarshan.t.raghavan>
sudarshan.t.raghavan> Thanks,
sudarshan.t.raghavan> Sudarshan
Your assumption is correct, OpenSSL expects the same semantics as
malloc(), realloc() and free(), so you free() replacement must be able
to handle a NULL argument.
ANSI C and POSIX free() is NOT required to handle free(NULL)
as a NOP.
ANSI C++ operator delete() is required to do this, but this
requirement does not extent to free() invoked from a C++ program.
Some libc implementations provide this feature anyway, but it
is not a required property of free(), and according to Dr.
Henson's reply above it is not a requirement of the OpenSSL
custom free() callback either.
Enjoy
Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S. http://www.wisemo.com
Transformervej 29, 2730 Herlev, Denmark. Direct +45 31 13 16 10
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