openssh bugs - Dec 2018 - [Bug 2938] New: minor memory leak during channel_init_channels()

https://bugzilla.mindrot.org/show_bug.cgi?id=2938

            Bug ID: 2938
           Summary: minor memory leak during channel_init_channels()
           Product: Portable OpenSSH
           Version: 7.9p1
          Hardware: ix86
                OS: All
            Status: NEW
          Severity: trivial
          Priority: P5
         Component: ssh
          Assignee: unassigned-bugs at mindrot.org
          Reporter: markus at blueflash.cc

Created attachment 3208
  --> https://bugzilla.mindrot.org/attachment.cgi?id=3208&action=edit
patch to fix memory leak

Note: This is my first contribution to the openssh source and I'm
porting my findings from a macOS/Windows port back to the original
source. So please be gentle with my possible wrongdoings and errors.


In any case, I think this should be pretty straightforward:

In channels.c there is the channel_init_channels() function, which
initially callocates memory for the sc structure and immediately also
callocates and fills the sc->channel_pre and sc->channel_post pointer
members.

Then, after a few lines of code, it finally calls the
channel_handler_init(sc) function.

Now, the channel channel_handler_init() also callocates memory for pre
and post and finally assigns its pointers into the sc struct pointer
members.

        sc->channel_pre = pre;
        sc->channel_post = post;

However, at this point, sc->channel_pre and sc->channel_post are
already filled with the pointers to the memory blocks which
channel_init_channels() had allocated.

Thus these pointers get lost and the memory blocks leak.


Proposal: don't have chanell_init_channel() allocate these.  Let
channel_init_channels() do it.


A patch is attached.

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https://bugzilla.mindrot.org/show_bug.cgi?id=2938

Markus <markus at blueflash.cc> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |markus at blueflash.cc

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https://bugzilla.mindrot.org/show_bug.cgi?id=2938

Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |djm at mindrot.org
   Attachment #3208|0                           |1
           is patch|                            |
   Attachment #3208|application/octet-stream    |text/plain
          mime type|                            |

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Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |2915
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #1 from Damien Miller <djm at mindrot.org> ---
Good catch - thanks! I've committed this and it will be in the
openssh-8.0 release.


Referenced Bugs:

https://bugzilla.mindrot.org/show_bug.cgi?id=2915
[Bug 2915] Tracking bug for 8.0 release
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Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #2 from Damien Miller <djm at mindrot.org> ---
Move resolved bugs -> CLOSED after 8.0 release

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Ahmed Sayeed <ahmedsayeed1982 at yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ahmedsayeed1982 at yahoo.com

--- Comment #3 from Ahmed Sayeed <ahmedsayeed1982 at yahoo.com> ---
ake: Entering directory '/home/Christian/binutils-gdb/cygwin-obj/gdb'
  CXXLD  gdb.exe  http://www.compilatori.com/computers/smartphones/
cp-support.o: in function `gdb_demangle(char const*, int)':
http://www.acpirateradio.co.uk/services/ios15/
/home/Christian/binutils-gdb/cygwin-obj/gdb/../../gdb/cp-support.c:1619:(.text+0x5502):
http://www.logoarts.co.uk/property/lidar-sensor/ relocation truncated
to fit: R_X86_64_PC32 against undefined symbol
http://www.slipstone.co.uk/property/hp-of-cars/ `TLS init function for
thread_local_segv_handler'
/home/Christian/binutils-gdb/cygwin-obj/gdb/../../gdb/cp-support.c:1619:(.text+0x551b):
http://embermanchester.uk/property/chat-themes/  relocation truncated
to fit: R_X86_64_PC32 against undefined symbol `TLS init function for
thread_local_segv_handler'
collect2: error: ld returned 1 exit status
http://connstr.net/property/mars-researches/
make: *** [Makefile:1881: gdb.exe] Error 1
make: Leaving directory '/home/Christian/binutils-gdb/cygwin-obj/gdb'
http://joerg.li/services/kia-rio-price/

$ g++ -v
Using built-in specs.
http://www.jopspeech.com/technology/thunderbolt-4/
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-cygwin/10/lto-wrapper.exe
Target: x86_64-pc-cygwin
http://www.wearelondonmade.com/tech/driving-assistant/ 
Configured with:
/mnt/share/cygpkgs/gcc/gcc.x86_64/src/gcc-10.2.0/configure
--srcdir=/mnt/share/cygpkgs/gcc/gcc.x86_64/src/gcc-10.2.0 --prefix=/usr
--exec-prefix=/usr --localstatedir=/var --sysconfdir=/etc
--docdir=/usr/share/doc/gcc --
https://waytowhatsnext.com/computers/discord-and-steam/
htmldir=/usr/share/doc/gcc/html -C --build=x86_64-pc-cygwin
--host=x86_64-pc-cygwin --target=x86_64-pc-cygwin
--without-libiconv-prefix --without-libintl-prefix --
http://www.iu-bloomington.com/property/properties-in-turkey/
libexecdir=/usr/lib --with-gcc-major-version-only --enable-shared
--enable-shared-libgcc --enable-static
--enable-version-specific-runtime-libs --enable-bootstrap
--enable-__cxa_atexit --with-dwarf2
https://komiya-dental.com/sports/telegram/ --with-tune=generic
--enable-languages=c,c++,fortran,lto,objc,obj-c++ --enable-graphite
--enable-threads=posix --enable-libatomic --enable-libgomp
--enable-libquadmath http://www-look-4.com/health/winter-sickness/
--enable-libquadmath-support --disable-libssp --enable-libada
--disable-symvers --with-gnu-ld --with-gnu-as
--with-cloog-include=/usr/include/cloog-isl --without-libiconv-prefix
--without-libintl-prefix --with-system-zlib
https://www.webb-dev.co.uk/sports/gym-during-covid/
--enable-linker-build-id --with-default-libstdcxx-abi=gcc4-compatible
--enable-libstdcxx-filesystem-ts
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.2.0 (GCC)

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