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author | David Kilroy <David.Kilroy@arm.com> | 2020-02-12 14:28:15 -0300 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2020-02-12 14:29:48 -0300 |
commit | eb447b7b4bd6177f876ba9420ad9e048c27bae91 (patch) | |
tree | cbde7ab262bfc6b74c6b4a7f9eb1984fdb3e6485 /elf/dl-open.c | |
parent | 6721b9d52e3bdc7cbec97e6b2952c523c14aebee (diff) | |
download | glibc-eb447b7b4bd6177f876ba9420ad9e048c27bae91.tar.gz glibc-eb447b7b4bd6177f876ba9420ad9e048c27bae91.tar.xz glibc-eb447b7b4bd6177f876ba9420ad9e048c27bae91.zip |
elf: Allow dlopen of filter object to work [BZ #16272]
There are two fixes that are needed to be able to dlopen filter objects. First _dl_map_object_deps cannot assume that map will be at the beginning of l_searchlist.r_list[], as filtees are inserted before map. Secondly dl_open_worker needs to ensure that filtees get relocated. In _dl_map_object_deps: * avoiding removing relocation dependencies of map by setting l_reserved to 0 and otherwise processing the rest of the search list. * ensure that map remains at the beginning of l_initfini - the list of things that need initialisation (and destruction). Do this by splitting the copy up. This may not be required, but matches the initialization order without dlopen. Modify dl_open_worker to relocate the objects in new->l_inifini. new->l_initfini is constructed in _dl_map_object_deps, and lists the objects that need initialization and destruction. Originally the list of objects in new->l_next are relocated. All of these objects should also be included in new->l_initfini (both lists are populated with dependencies in _dl_map_object_deps). We can't use new->l_prev to pick up filtees, as during a recursive dlopen from an interposed malloc call, l->prev can contain objects that are not ready for relocation. Add tests to verify that symbols resolve to the filtee implementation when auxiliary and filter objects are used, both as a normal link and when dlopen'd. Tested by running the testsuite on x86_64.
Diffstat (limited to 'elf/dl-open.c')
-rw-r--r-- | elf/dl-open.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/elf/dl-open.c b/elf/dl-open.c index 623c9754eb..ecb2ba9cc1 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -621,22 +621,25 @@ dl_open_worker (void *a) allows IFUNC relocations to work and it also means copy relocation of dependencies are if necessary overwritten. */ unsigned int nmaps = 0; - struct link_map *l = new; + unsigned int j = 0; + struct link_map *l = new->l_initfini[0]; do { if (! l->l_real->l_relocated) ++nmaps; - l = l->l_next; + l = new->l_initfini[++j]; } while (l != NULL); + /* Stack allocation is limited by the number of loaded objects. */ struct link_map *maps[nmaps]; nmaps = 0; - l = new; + j = 0; + l = new->l_initfini[0]; do { if (! l->l_real->l_relocated) maps[nmaps++] = l; - l = l->l_next; + l = new->l_initfini[++j]; } while (l != NULL); _dl_sort_maps (maps, nmaps, NULL, false); |