diff --git a/elf/Makefile b/elf/Makefile index 18b59a8632..67052b5694 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -498,6 +498,7 @@ tests += \ tst-unique2 \ tst-unwind-ctor \ tst-unwind-main \ + tst-version-hash-zero \ unload3 \ unload4 \ unload5 \ @@ -1035,6 +1036,9 @@ modules-names += \ tst-unique2mod1 \ tst-unique2mod2 \ tst-unwind-ctor-lib \ + tst-version-hash-zero-linkmod \ + tst-version-hash-zero-mod \ + tst-version-hash-zero-refmod \ unload2dep \ unload2mod \ unload3mod1 \ @@ -3412,3 +3416,20 @@ $(objpfx)tst-nolink-libc-2: $(objpfx)tst-nolink-libc.o -Wl,--dynamic-linker=$(objpfx)ld.so $(objpfx)tst-nolink-libc-2.out: $(objpfx)tst-nolink-libc-2 $(objpfx)ld.so $< > $@ 2>&1; $(evaluate-test) + +$(objpfx)tst-version-hash-zero.out: \ + $(objpfx)tst-version-hash-zero-mod.so \ + $(objpfx)tst-version-hash-zero-refmod.so +LDFLAGS-tst-version-hash-zero-mod.so = \ + -Wl,--version-script=tst-version-hash-zero-mod.map +# The run-time test module tst-version-hash-zero-refmod.so is linked +# to a stub module, tst-version-hash-zero-linkmod.so, to produce an +# expected relocation error. +$(objpfx)tst-version-hash-zero-refmod.so: \ + $(objpfx)tst-version-hash-zero-linkmod.so +LDFLAGS-tst-version-hash-zero-linkmod.so = \ + -Wl,--version-script=tst-version-hash-zero-linkmod.map \ + -Wl,--soname=tst-version-hash-zero-mod.so +$(objpfx)tst-version-hash-zero-refmod.so: \ + $(objpfx)tst-version-hash-zero-linkmod.so +tst-version-hash-zero-refmod.so-no-z-defs = yes diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index ece647f009..2f5cd674f5 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -100,12 +100,22 @@ check_match (const char *const undef_name, /* We can match the version information or use the default one if it is not hidden. */ ElfW(Half) ndx = verstab[symidx] & 0x7fff; - if ((map->l_versions[ndx].hash != version->hash - || strcmp (map->l_versions[ndx].name, version->name)) - && (version->hidden || map->l_versions[ndx].hash - || (verstab[symidx] & 0x8000))) - /* It's not the version we want. */ - return NULL; + if (map->l_versions[ndx].hash == version->hash + && strcmp (map->l_versions[ndx].name, version->name) == 0) + /* This is an exact version match. Return the symbol below. */ + ; + else + { + if (!version->hidden + && map->l_versions[ndx].name[0] == '\0' + && (verstab[symidx] & 0x8000) == 0 + && (*num_versions)++ == 0) + /* This is the global default version. Store it as a + fallback match. */ + *versioned_sym = sym; + + return NULL; + } } } else diff --git a/elf/dl-version.c b/elf/dl-version.c index d414bd1e18..2fbf4942b9 100644 --- a/elf/dl-version.c +++ b/elf/dl-version.c @@ -357,6 +357,13 @@ _dl_check_map_versions (struct link_map *map, int verbose, int trace_mode) ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next); } } + + /* The empty string has ELF hash zero. This avoids a NULL check + before the version string comparison in check_match in + dl-lookup.c. */ + for (unsigned int i = 0; i < map->l_nversions; ++i) + if (map->l_versions[i].name == NULL) + map->l_versions[i].name = ""; } /* When there is a DT_VERNEED entry with libc.so on DT_NEEDED, issue diff --git a/elf/tst-version-hash-zero-linkmod.c b/elf/tst-version-hash-zero-linkmod.c new file mode 100644 index 0000000000..15e2506d01 --- /dev/null +++ b/elf/tst-version-hash-zero-linkmod.c @@ -0,0 +1,22 @@ +/* Stub module for linking tst-version-hash-zero-refmod.so. + Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, see . */ + +/* The version script assigns a different symbol version for the stub + module. Loading the module with the incorrect version is expected + to fail. */ +#include "tst-version-hash-zero-mod.c" diff --git a/elf/tst-version-hash-zero-linkmod.map b/elf/tst-version-hash-zero-linkmod.map new file mode 100644 index 0000000000..2dba7c22d7 --- /dev/null +++ b/elf/tst-version-hash-zero-linkmod.map @@ -0,0 +1,7 @@ +Base { + local: *; +}; + +OTHER_VERSION { + global: global_variable; +} Base; diff --git a/elf/tst-version-hash-zero-mod.c b/elf/tst-version-hash-zero-mod.c new file mode 100644 index 0000000000..ac6b0dc4a5 --- /dev/null +++ b/elf/tst-version-hash-zero-mod.c @@ -0,0 +1,20 @@ +/* Test module with a zero version symbol hash. + Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, see . */ + +/* The symbol version is assigned by version script. */ +int global_variable; diff --git a/elf/tst-version-hash-zero-mod.map b/elf/tst-version-hash-zero-mod.map new file mode 100644 index 0000000000..41eaff7914 --- /dev/null +++ b/elf/tst-version-hash-zero-mod.map @@ -0,0 +1,13 @@ +Base { + local: *; +}; + +/* Define the version so that tst-version-hash-zero-refmod.so passes + the initial symbol version check. */ +OTHER_VERSION { +} Base; + +/* This version string hashes to zero. */ +PPPPPPPPPPPP { + global: global_variable; +} Base; diff --git a/elf/tst-version-hash-zero-refmod.c b/elf/tst-version-hash-zero-refmod.c new file mode 100644 index 0000000000..cd8b3dcef5 --- /dev/null +++ b/elf/tst-version-hash-zero-refmod.c @@ -0,0 +1,23 @@ +/* Test module that triggers a relocation failure in tst-version-hash-zero. + Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, see . */ + +/* This is bound to global_variable@@OTHER_VERSION via + tst-version-hash-zero-linkmod.so, but at run time, only + global_variable@PPPPPPPPPPPP exists. */ +extern int global_variable; +int *pointer_variable = &global_variable; diff --git a/elf/tst-version-hash-zero.c b/elf/tst-version-hash-zero.c new file mode 100644 index 0000000000..66a0db4f51 --- /dev/null +++ b/elf/tst-version-hash-zero.c @@ -0,0 +1,56 @@ +/* Symbols with version hash zero should not match any version (bug 29190). + Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, see . */ + +#include +#include +#include +#include + +static int +do_test (void) +{ + void *handle = xdlopen ("tst-version-hash-zero-mod.so", RTLD_NOW); + + /* This used to crash because some struct r_found_version entries + with hash zero did not have valid version strings. */ + TEST_VERIFY (xdlvsym (handle, "global_variable", "PPPPPPPPPPPP") != NULL); + + /* Consistency check. */ + TEST_VERIFY (xdlsym (handle, "global_variable") + == xdlvsym (handle, "global_variable", "PPPPPPPPPPPP")); + + /* This symbol version is supposed to be missing. */ + TEST_VERIFY (dlvsym (handle, "global_variable", "OTHER_VERSION") == NULL); + + /* tst-version-hash-zero-refmod.so references + global_variable@@OTHER_VERSION and is expected to fail to load. + dlvsym sets the hidden flag during lookup. Relocation does not, + so this exercises a different failure case. */ + TEST_VERIFY_EXIT (dlopen ("tst-version-hash-zero-refmod.so", RTLD_NOW) + == NULL); + const char *message = dlerror (); + if (strstr (message, + ": undefined symbol: global_variable, version OTHER_VERSION") + == NULL) + FAIL_EXIT1 ("unexpected dlopen failure: %s", message); + + xdlclose (handle); + return 0; +} + +#include