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elf: Fix failure handling in _dl_map_object_from_fd 

The failure paths in _dl_map_object_from_fd did not clean every
potentially allocated resource up.

Handle l_phdr, l_libname and mapped segments in the common failure
handling code.

There are various bits that may not be cleaned properly on failure
(e.g. executable stack, incomplete dl_map_segments) fixing those
need further changes.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Szabolcs Nagy 2020-11-24 12:34:39 +00:00
parent cb5648b00f
commit c6b0165327
1 changed files with 15 additions and 10 deletions
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25
elf/dl-load.c
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@ -955,8 +955,14 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
/* The file might already be closed. */ /* The file might already be closed. */
if (fd != -1) if (fd != -1)
__close_nocancel (fd); __close_nocancel (fd);
if (l != NULL && l->l_map_start != 0)
_dl_unmap_segments (l);
if (l != NULL && l->l_origin != (char *) -1l) if (l != NULL && l->l_origin != (char *) -1l)
free ((char *) l->l_origin); free ((char *) l->l_origin);
if (l != NULL && !l->l_libname->dont_free)
free (l->l_libname);
if (l != NULL && l->l_phdr_allocated)
free ((void *) l->l_phdr);
free (l); free (l);
free (realname); free (realname);
@ -1251,7 +1257,11 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds, errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds,
maplength, has_holes, loader); maplength, has_holes, loader);
if (__glibc_unlikely (errstring != NULL)) if (__glibc_unlikely (errstring != NULL))
goto lose; {
/* Mappings can be in an inconsistent state: avoid unmap. */
l->l_map_start = l->l_map_end = 0;
goto lose;
}
} }
if (l->l_ld == 0) if (l->l_ld == 0)
@ -1274,15 +1284,6 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
|| (__glibc_unlikely (l->l_flags_1 & DF_1_PIE) || (__glibc_unlikely (l->l_flags_1 & DF_1_PIE)
&& __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0))) && __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0)))
{ {
/* We are not supposed to load this object. Free all resources. */
_dl_unmap_segments (l);
if (!l->l_libname->dont_free)
free (l->l_libname);
if (l->l_phdr_allocated)
free ((void *) l->l_phdr);
if (l->l_flags_1 & DF_1_PIE) if (l->l_flags_1 & DF_1_PIE)
errstring errstring
= N_("cannot dynamically load position-independent executable"); = N_("cannot dynamically load position-independent executable");
@ -1387,6 +1388,10 @@ cannot enable executable stack as shared object requires");
/* Signal that we closed the file. */ /* Signal that we closed the file. */
fd = -1; fd = -1;
/* Failures before this point are handled locally via lose.
There are no more failures in this function until return,
to change that the cleanup handling needs to be updated. */
/* If this is ET_EXEC, we should have loaded it as lt_executable. */ /* If this is ET_EXEC, we should have loaded it as lt_executable. */
assert (type != ET_EXEC || l->l_type == lt_executable); assert (type != ET_EXEC || l->l_type == lt_executable);