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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2018-08-27 16:16:43 -0300 |
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| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2018-09-25 16:27:50 -0300 |
| commit | b5c45e83753b27dc538dff2d55d4410c385cf3a4 (patch) | |
| tree | 7c88e09f3bcf2edbdf2a1196b50c54ab7459b0c5 /config.make.in | |
| parent | d62f9ec0cce26a275ec68f4564814041a33395b1 (diff) | |
| download | glibc-b5c45e83753b27dc538dff2d55d4410c385cf3a4.tar.gz glibc-b5c45e83753b27dc538dff2d55d4410c385cf3a4.tar.xz glibc-b5c45e83753b27dc538dff2d55d4410c385cf3a4.zip | |
Fix ifunc support with DT_TEXTREL segments (BZ#20480)
Currently, DT_TEXTREL is incompatible with IFUNC. When DT_TEXTREL or DF_TEXTREL is seen, the dynamic linker calls __mprotect on the segments with PROT_READ|PROT_WRITE before applying dynamic relocations. It leads to segfault when performing IFUNC resolution (which requires PROT_EXEC as well for the IFUNC resolver). This patch makes it call __mprotect with extra PROT_WRITE bit, which will keep the PROT_EXEC bit if exists, and thus fixes the segfault. FreeBSD rtld libexec/rtld-elf/rtld.c (reloc_textrel_prot) does the same. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, sparc64-linux-gnu, sparcv9-linux-gnu, and armv8-linux-gnueabihf. Adam J. Richte <adam_richter2004@yahoo.com> Adhemerval Zanella <adhemerval.zanella@linaro.org> Fangrui Song <maskray@google.com> [BZ #20480] * config.h.in (CAN_TEXTREL_IFUNC): New define. * configure.ac: Add check if linker supports textrel relocation with ifunc. * elf/dl-reloc.c (_dl_relocate_object): Use all required flags on DT_TEXTREL segments, not only PROT_READ and PROT_WRITE. * elf/Makefile (ifunc-pie-tests): Add tst-ifunc-textrel. (CFLAGS-tst-ifunc-textrel.c): New rule. * elf/tst-ifunc-textrel.c: New file.
Diffstat (limited to 'config.make.in')
| -rw-r--r-- | config.make.in | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/config.make.in b/config.make.in index a6fe48d31f..f46bfc29bb 100644 --- a/config.make.in +++ b/config.make.in @@ -75,6 +75,7 @@ use-default-link = @use_default_link@ output-format = @libc_cv_output_format@ have-cxx-thread_local = @libc_cv_cxx_thread_local@ have-loop-to-function = @libc_cv_cc_loop_to_function@ +have-textrel_ifunc = @libc_cv_textrel_ifunc@ multi-arch = @multi_arch@ |