lib/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2025-08-08 17:42:12 +03:00
Code Activity

ld.so: Support moving versioned symbols between sonames [BZ #24741]

Browse Source 
This change should be fully backwards-compatible because the old
code aborted the load if a soname mismatch was encountered
(instead of searching further for a matching symbol).  This means
that no different symbols are found.

The soname check was explicitly disabled for the skip_map != NULL
case.  However, this only happens with dl(v)sym and RTLD_NEXT,
and those lookups do not come with a verneed entry that could be used
for the check.

The error check was already explicitly disabled for the skip_map !=
NULL case, that is, when dl(v)sym was called with RTLD_NEXT.  But
_dl_vsym always sets filename in the struct r_found_version argument
to NULL, so the check was not active anyway.  This means that
symbol lookup results for the skip_map != NULL case do not change,
either.
This commit is contained in:
Florian Weimer
2019-06-28 10:12:50 +02:00
parent 17432d7150
commit f0b2132b35
12 changed files with 223 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
elf/dl-lookup.c
View File

@@ -536,11 +536,7 @@ do_lookup_x (const char *undef_name, uint_fast32_t new_hash,
}
skip:
/* If this current map is the one mentioned in the verneed entry
and we have not found a weak entry, it is a bug. */
if (symidx == STN_UNDEF && version != NULL && version->filename != NULL
&& __glibc_unlikely (_dl_name_match_p (version->filename, map)))
return -1;
;
}
while (++i < n);
@@ -810,34 +806,10 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
/* Search the relevant loaded objects for a definition. */
for (size_t start = i; *scope != NULL; start = 0, ++scope)
{
int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref,
&current_value, *scope, start, version, flags,
skip_map, type_class, undef_map);
if (res > 0)
break;
if (__glibc_unlikely (res < 0) && skip_map == NULL)
{
/* Oh, oh. The file named in the relocation entry does not
contain the needed symbol. This code is never reached
for unversioned lookups. */
assert (version != NULL);
const char *reference_name = undef_map ? undef_map->l_name : "";
struct dl_exception exception;
/* XXX We cannot translate the message. */
_dl_exception_create_format
(&exception, DSO_FILENAME (reference_name),
"symbol %s version %s not defined in file %s"
" with link time reference%s",
undef_name, version->name, version->filename,
res == -2 ? " (no version symbols)" : "");
_dl_signal_cexception (0, &exception, N_("relocation error"));
_dl_exception_free (&exception);
*ref = NULL;
return 0;
}
}
if (do_lookup_x (undef_name, new_hash, &old_hash, *ref,
&current_value, *scope, start, version, flags,
skip_map, type_class, undef_map) != 0)
break;
if (__glibc_unlikely (current_value.s == NULL))
{