[Bug 1731325] [NEW] dlopen crashed with Segmentation Fault

[Sankar Tanguturi]

Public bug reported:

In one of our applications, we use dlopen to open a bunch of library
(.so) files in the following order:

1. zlib 1.2.8 version (not the one bundled in Ubuntu 17.10)
2. gtk-x11-2.0.so.0 bundled in the system
3. libSM.so.6 bundled in the system

The dlopen api crashes with 'Segmentation fault' when opening
libSM.so.6. You can reproduce the issue using the following simple
program.

Sample C program:
=================
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>

int
main(int argc, char **argv)
{
  int i;
  for (i = 1; i < argc; i++) {
   void *handle;
   printf("Opening %s\n", argv[i]);
   handle = dlopen(argv[i], RTLD_LAZY | RTLD_LOCAL);
    if (!handle) {
        printf("Error: %s\n", dlerror());
    }
  }
  exit(EXIT_SUCCESS);
}

Compile and run as follows:
$ ./a.out /path/to/libz/versio/1.2.8 /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0 libSM.so.6

Note:
- We encountered this issue only in Ubuntu 17.10. In ubuntu 17.04, we didn't have any issue. May be this is an issue with the latest glibc. Not sure.

Investigation done:
- dlopen initially passes while opening zlib version.
- dlopen fails to open libgtk-x11-2.0.so.0 with the following error:

Error: /usr/lib/vmware-tools/lib/libz.so.1/libz.so.1: version
`ZLIB_1.2.9' not found (required by /usr/lib/x86_64-linux-
gnu/libpng16.so.16)

And then dlopen for libSM.so.6 core dumps.

I understand that the zlib 1.2.8 doesn't provide the necessary required
version and hence dlopen for gtk failed. But why does dlopen crash for
libSM.so.6?

- I executed valgrind command and attaching the output.

Please let me know if any other information is required.

Thanks
Sankar.

** Affects: glibc (Ubuntu)
     Importance: Undecided
         Status: New

** Attachment added: "output of valgrind"
   https://bugs.launchpad.net/bugs/1731325/+attachment/5006643/+files/valgrind.output

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https://bugs.launchpad.net/bugs/1731325

Title:
  dlopen crashed with Segmentation Fault

Status in glibc package in Ubuntu:
  New

Bug description:
  In one of our applications, we use dlopen to open a bunch of library
  (.so) files in the following order:

  1. zlib 1.2.8 version (not the one bundled in Ubuntu 17.10)
  2. gtk-x11-2.0.so.0 bundled in the system
  3. libSM.so.6 bundled in the system

  The dlopen api crashes with 'Segmentation fault' when opening
  libSM.so.6. You can reproduce the issue using the following simple
  program.

  Sample C program:
  =================
  #include <stdio.h>
  #include <stdlib.h>
  #include <dlfcn.h>

  int
  main(int argc, char **argv)
  {
    int i;
    for (i = 1; i < argc; i++) {
     void *handle;
     printf("Opening %s\n", argv[i]);
     handle = dlopen(argv[i], RTLD_LAZY | RTLD_LOCAL);
      if (!handle) {
          printf("Error: %s\n", dlerror());
      }
    }
    exit(EXIT_SUCCESS);
  }

  Compile and run as follows:
  $ ./a.out /path/to/libz/versio/1.2.8 /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0 libSM.so.6

  Note:
  - We encountered this issue only in Ubuntu 17.10. In ubuntu 17.04, we didn't have any issue. May be this is an issue with the latest glibc. Not sure.

  Investigation done:
  - dlopen initially passes while opening zlib version.
  - dlopen fails to open libgtk-x11-2.0.so.0 with the following error:

  Error: /usr/lib/vmware-tools/lib/libz.so.1/libz.so.1: version
  `ZLIB_1.2.9' not found (required by /usr/lib/x86_64-linux-
  gnu/libpng16.so.16)

  And then dlopen for libSM.so.6 core dumps.

  I understand that the zlib 1.2.8 doesn't provide the necessary
  required version and hence dlopen for gtk failed. But why does dlopen
  crash for libSM.so.6?

  - I executed valgrind command and attaching the output.

  Please let me know if any other information is required.

  Thanks
  Sankar.

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