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elf: do not substitute dst in $LD_LIBRARY_PATH twice [BZ #22627] 

Starting with commit
glibc-2.18.90-470-g2a939a7e6d81f109d49306bc2e10b4ac9ceed8f9 that
introduced substitution of dynamic string tokens in fillin_rpath,
_dl_init_paths invokes _dl_dst_substitute for $LD_LIBRARY_PATH twice:
the first time it's called directly, the second time the result
is passed on to fillin_rpath which calls expand_dynamic_string_token
which in turn calls _dl_dst_substitute, leading to the following
behaviour:

$ mkdir -p /tmp/'$ORIGIN' && cd /tmp/'$ORIGIN' &&
  echo 'int main(){}' |gcc -xc - &&
  strace -qq -E LD_LIBRARY_PATH='$ORIGIN' -e /open ./a.out
open("/tmp//tmp/$ORIGIN/tls/x86_64/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("/tmp//tmp/$ORIGIN/tls/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("/tmp//tmp/$ORIGIN/x86_64/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("/tmp//tmp/$ORIGIN/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
open("/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3

Fix this by removing the direct _dl_dst_substitute invocation.

* elf/dl-load.c (_dl_init_paths): Remove _dl_dst_substitute preparatory
code and invocation.
This commit is contained in:
Dmitry V. Levin 2017-12-17 23:49:46 +00:00
parent 14d886edbd
commit bb195224ac
2 changed files with 7 additions and 19 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
2017-12-18 Dmitry V. Levin <ldv@altlinux.org>
[BZ #22627]
* elf/dl-load.c (_dl_init_paths): Remove _dl_dst_substitute preparatory
code and invocation.
2017-12-18 Szabolcs Nagy <szabolcs.nagy@arm.com>
* sysdeps/aarch64/start.S (_start): Handle PIC && !SHARED case.

20
elf/dl-load.c
View File

@ -773,25 +773,7 @@ _dl_init_paths (const char *llp)
if (llp != NULL && *llp != '\0')
{
char *llp_tmp;
#ifdef SHARED
/* Expand DSTs. */
size_t cnt = DL_DST_COUNT (llp, 1);
if (__glibc_likely (cnt == 0))
llp_tmp = strdupa (llp);
else
{
/* Determine the length of the substituted string. */
size_t total = DL_DST_REQUIRED (l, llp, strlen (llp), cnt);
/* Allocate the necessary memory. */
llp_tmp = (char *) alloca (total + 1);
llp_tmp = _dl_dst_substitute (l, llp, llp_tmp, 1);
}
#else
llp_tmp = strdupa (llp);
#endif
char *llp_tmp = strdupa (llp);
/* Decompose the LD_LIBRARY_PATH contents. First determine how many
elements it has. */