Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
On 16.08.21 05:14, John Reiser wrote: I'd need help with the following issue with apitrace, which failed the mass rebuild with: apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:70: undefined reference to `__libc_dlopen_mode' apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:72: undefined reference to `__libc_dlsym' The code triggering this is below. Have these symbols disappeared from libc resp is there any alternative? I've raised this upstream but so far no activity [1]. I'm not really knowledgeable enough in this area to judge the best way to fix this. Is anyone able to help with this? Otherwise I'll have to orphain/retire apitrace for F35+. According to the comments in https://github.com/apitrace/apitrace.git file wrappers/dlsym.cpp , the purpose is "to obtain the true dlsym" by explicit lookup in libdl.so.2, which is a library that no longer exists in glibc-2.34, having been combined into libc.so itself. The only legitimate way to find "the true dlsym" is to trust dl_iterate_phdr (/usr/include/link.h) and call it, dig through all the Dynamic sections to find all the symbols named 'dlsym', then choose the one you want: perhaps by being defined in a file whose DT_SONAME is "libc.so" and having symbol version GLIBC_2.2.5 . Because such code has not been contributed, then apitrace should be orphaned/retired in F35+. Thanks for your reply - I've forwarded your comment upstream. The package will be retired in ca 5 weeks if no solution presents itself until then. Sandro ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
I'd need help with the following issue with apitrace, which failed the mass rebuild with: apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:70: undefined reference to `__libc_dlopen_mode' apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:72: undefined reference to `__libc_dlsym' The code triggering this is below. Have these symbols disappeared from libc resp is there any alternative? I've raised this upstream but so far no activity [1]. I'm not really knowledgeable enough in this area to judge the best way to fix this. Is anyone able to help with this? Otherwise I'll have to orphain/retire apitrace for F35+. According to the comments in https://github.com/apitrace/apitrace.git file wrappers/dlsym.cpp , the purpose is "to obtain the true dlsym" by explicit lookup in libdl.so.2, which is a library that no longer exists in glibc-2.34, having been combined into libc.so itself. The only legitimate way to find "the true dlsym" is to trust dl_iterate_phdr (/usr/include/link.h) and call it, dig through all the Dynamic sections to find all the symbols named 'dlsym', then choose the one you want: perhaps by being defined in a file whose DT_SONAME is "libc.so" and having symbol version GLIBC_2.2.5 . Because such code has not been contributed, then apitrace should be orphaned/retired in F35+. ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
On 25.07.21 12:51, Sandro Mani wrote: Hi I'd need help with the following issue with apitrace, which failed the mass rebuild with: apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:70: undefined reference to `__libc_dlopen_mode' apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:72: undefined reference to `__libc_dlsym' The code triggering this is below. Have these symbols disappeared from libc resp is there any alternative? I've raised this upstream but so far no activity [1]. I'm not really knowledgeable enough in this area to judge the best way to fix this. Is anyone able to help with this? Otherwise I'll have to orphain/retire apitrace for F35+. Thanks Sandro [1] https://github.com/apitrace/apitrace/issues/756 ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
Depending on the threat model, then DT_BIND_NOW and/or LD_PRELOAD can be used to find the desired instance of dlsym(). Also there is dl_iterate_phdr() (declared in /usr/include/link.h) which enables examination of all the symbols known to the runtime linker. ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
* Nicholas Miell: > On 7/25/21 4:28 AM, Florian Weimer wrote: >> * Sandro Mani: >> >>> I'd need help with the following issue with apitrace, which failed the >>> mass rebuild with: >>> >>> apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:70: >>> undefined reference to `__libc_dlopen_mode' >>> apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:72: >>> undefined reference to `__libc_dlsym' >>> >>> The code triggering this is below. Have these symbols disappeared from >>> libc resp is there any alternative? >> >> These internal GLIBC_PRIVATE symbols are gone and won't come back. >> >> Not sure why this code isn't using RTLD_NEXT. >> > > Because they're interposing dlsym itself and attempting to call > dlsym(RTLD_NEXT, ...) resolves to the interposed dlsym function and > dies due to infinite recursion. Oops, I see. >> We are working on improving LD_AUDIT support, which is the plugin API of >> the dynamic loader. It can in theory be used to implement such things. >> But API tracing is probably best implemented within the traced libraries >> themselves, rather than on the side. >> > > This isn't viable when you have multiple libraries from different > vendors, some or all of which are beyond your control. Which part? The tracing-in-libraries aspect? LD_AUDIT shouldn't have this problem. Dyninst and Systemtap might alos be worth investigation. Thanks, Florian ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
On 7/25/21 4:28 AM, Florian Weimer wrote: > * Sandro Mani: > >> I'd need help with the following issue with apitrace, which failed the >> mass rebuild with: >> >> apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:70: >> undefined reference to `__libc_dlopen_mode' >> apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:72: >> undefined reference to `__libc_dlsym' >> >> The code triggering this is below. Have these symbols disappeared from >> libc resp is there any alternative? > > These internal GLIBC_PRIVATE symbols are gone and won't come back. > > Not sure why this code isn't using RTLD_NEXT. > Because they're interposing dlsym itself and attempting to call dlsym(RTLD_NEXT, ...) resolves to the interposed dlsym function and dies due to infinite recursion. > We are working on improving LD_AUDIT support, which is the plugin API of > the dynamic loader. It can in theory be used to implement such things. > But API tracing is probably best implemented within the traced libraries > themselves, rather than on the side. > This isn't viable when you have multiple libraries from different vendors, some or all of which are beyond your control. ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
We are working on improving LD_AUDIT support, which is the plugin API of the dynamic loader. It can in theory be used to implement such things. Depending on the threat model, then DT_BIND_NOW and/or LD_PRELOAD can be used to find the desired instance of dlsym(). If the threats include "just in time" modification of the instruction stream, then you must control the system calls execve, mmap, mprotect, and ptrace. -- ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
Re: apitrace: undefined reference to `__libc_dlopen_mode', `__libc_dlsym'
* Sandro Mani: > I'd need help with the following issue with apitrace, which failed the > mass rebuild with: > > apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:70: > undefined reference to `__libc_dlopen_mode' > apitrace-9d42f667e2a36a6624d92b9bd697de097cc4e619/wrappers/dlsym.cpp:72: > undefined reference to `__libc_dlsym' > > The code triggering this is below. Have these symbols disappeared from > libc resp is there any alternative? These internal GLIBC_PRIVATE symbols are gone and won't come back. Not sure why this code isn't using RTLD_NEXT. We are working on improving LD_AUDIT support, which is the plugin API of the dynamic loader. It can in theory be used to implement such things. But API tracing is probably best implemented within the traced libraries themselves, rather than on the side. Thanks, Florian ___ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
