Bug 229708
| Summary: | Don't require the program header for ELF files fit in the first page | ||||||
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| Product: | Base System | Reporter: | Alex Arslan <ararslan> | ||||
| Component: | bin | Assignee: | Konstantin Belousov <kib> | ||||
| Status: | Closed FIXED | ||||||
| Severity: | Affects Some People | CC: | cem, emaste, grahamperrin, iwtcex, kib, lantw44, lwhsu, trueos | ||||
| Priority: | --- | ||||||
| Version: | 11.2-RELEASE | ||||||
| Hardware: | Any | ||||||
| OS: | Any | ||||||
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Description
Alex Arslan
2018-07-11 20:33:48 UTC
https://reviews.freebsd.org/D26323 Can somebody provide a usable test case ? I mean, the binary and dep library, where library has phdrs outside page 0 ? Also, do you want same for binaries ? Our kernel activator does not handle it either. If yes, this would be a separate change. (In reply to Konstantin Belousov from comment #1) Well, supposedly patchelf produces such executables, although reading [1] https://github.com/NixOS/patchelf/issues/153 and especially [2] gives me the impression this might have been fixed in the meantime. Another potential use case is Widevine CDM (obtainable from [3] and [4]), which I intend to test with Firefox/Chromium and my glibc ABI compatibility hack ([5], think linuxpluginwrapper, but more reliable) to see how feasible that approach actually is. % env LD_PRELOAD=$PWD/libwidevinecdm.so true ld-elf.so.1: .../libwidevinecdm.so: program header too large % readelf -h libwidevinecdm.so ... Start of program headers: 9300548 (bytes into file) Start of section headers: 9301776 (bytes into file) Since this is a proprietary closed source library, I don't know how it was built. > Also, do you want same for binaries ? Likely not. [1] https://github.com/NixOS/patchelf/issues/153 [2] https://github.com/NixOS/patchelf/issues/165#issuecomment-477084014 [3] https://dl.google.com/widevine-cdm/4.10.1582.2-linux-x64.zip [4] https://dl.google.com/widevine-cdm/4.10.1582.2-linux-ia32.zip [5] https://github.com/shkhln/nvshim orion% LD_PRELOAD=/tmp/libwidevinecdm.so obj/usr/home/kostik/work/build/bsd/DEV/src/amd64.amd64/libexec/rtld-elf/ld-elf.so.1 /bin/ls ld-elf.so.1: Shared object "libpthread.so.0" not found, required by "libwidevinecdm.so" Which indicates that phdrs were parsed relatively ok-ish. Still I need a *FreeBSD* amd64 or i386 library with phdrs out of page 0, that I can link to some binary or dlopen(). If there is some function symbol that can be called (so I see that other processing was fine) it would be ideal. (In reply to Konstantin Belousov from comment #3) Or rebuild your instance of rtld with the patch in D26323 and check. (In reply to Konstantin Belousov from comment #3) > Still I need a *FreeBSD* amd64 or i386 library with phdrs out of page 0, > that I can link to some binary or dlopen(). Downgrading patchelf to 0.9 is the only option then. (In reply to Konstantin Belousov from comment #4) > Or rebuild your instance of rtld with the patch in D26323 and check. The patch works with my simplistic tests. Widevine eventually crashes for some other rtld-related reason. (Should I file a bug specifically for it? I'm doing this out of curiosity, not strict necessity.) (In reply to Alex S from comment #5) So will you supply me with the library ? Feel free to report additional issue there, or in new PR. In the later case, add me to PR, so I note it. Created attachment 217754 [details] executable (In reply to Konstantin Belousov from comment #6) > So will you supply me with the library ? % uname -a FreeBSD desktop 12.1-RELEASE-p8 FreeBSD 12.1-RELEASE-p8 GENERIC amd64 % cat libhello.c #include <stdio.h> __attribute__((constructor)) void hello() { printf("Hello there\n"); } % cc -fPIC -shared libhello.c -o libhello.so % .../patchelf --version patchelf 0.9 % .../patchelf --set-soname hellothere.so libhello.so % readelf -h libhello.so ... Start of program headers: 20480 (bytes into file) Start of section headers: 15048 (bytes into file) (In reply to Konstantin Belousov from comment #6) > Feel free to report additional issue there, or in new PR. In the later case, add me to PR, so I note it. Looks like libwidevinecdm.so in a typical Google fashion overrides (c|m|re|)alloc, so the crash is 100% their fault. Thank you, this was useful: orion% ./test ~/build/bsd/DEV/stuff/tests/RTLD/phdr_not_zero_page Hello there Hello there A commit references this bug: Author: kib Date: Sat Sep 5 10:16:24 UTC 2020 New revision: 365360 URL: https://svnweb.freebsd.org/changeset/base/365360 Log: rtld: Handle ELF dso with program headers outside the first page. Reported by: Alex Arslan <alex.arslan@julialang.org> PR: 229708 Reviewed by: dim (previous version), emaste Sponsored by: The FreeBSD Foundation Differential revision: https://reviews.freebsd.org/D26323 Changes: head/libexec/rtld-elf/map_object.c A commit references this bug: Author: kib Date: Fri Sep 11 10:05:44 UTC 2020 New revision: 365627 URL: https://svnweb.freebsd.org/changeset/base/365627 Log: MFC r365360, r365370: rtld: Handle ELF dso with program headers outside the first page. PR: 229708 Changes: _U stable/12/ stable/12/libexec/rtld-elf/map_object.c A commit references this bug: Author: kib Date: Fri Sep 11 10:11:04 UTC 2020 New revision: 365629 URL: https://svnweb.freebsd.org/changeset/base/365629 Log: MFC r365360, r365370: rtld: Handle ELF dso with program headers outside the first page. PR: 229708 Changes: _U stable/11/ stable/11/libexec/rtld-elf/map_object.c |
