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/* Audit common functions.
Copyright (C) 2021 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; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <ldsodefs.h>
void
_dl_audit_activity_map (struct link_map *l, int action)
{
struct audit_ifaces *afct = GLRO(dl_audit);
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->activity != NULL)
afct->activity (&link_map_audit_state (l, cnt)->cookie, action);
afct = afct->next;
}
}
void
_dl_audit_activity_nsid (Lmid_t nsid, int action)
{
/* If head is NULL, the namespace has become empty, and the audit interface
does not give us a way to signal LA_ACT_CONSISTENT for it because the
first loaded module is used to identify the namespace. */
struct link_map *head = GL(dl_ns)[nsid]._ns_loaded;
if (__glibc_likely (GLRO(dl_naudit) == 0)
|| head == NULL || head->l_auditing)
return;
_dl_audit_activity_map (head, action);
}
const char *
_dl_audit_objsearch (const char *name, struct link_map *l, unsigned int code)
{
if (l == NULL || l->l_auditing || code == 0)
return name;
struct audit_ifaces *afct = GLRO(dl_audit);
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->objsearch != NULL)
{
struct auditstate *state = link_map_audit_state (l, cnt);
name = afct->objsearch (name, &state->cookie, code);
if (name == NULL)
return NULL;
}
afct = afct->next;
}
return name;
}
void
_dl_audit_objopen (struct link_map *l, Lmid_t nsid)
{
if (__glibc_likely (GLRO(dl_naudit) == 0))
return;
struct audit_ifaces *afct = GLRO(dl_audit);
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->objopen != NULL)
{
struct auditstate *state = link_map_audit_state (l, cnt);
state->bindflags = afct->objopen (l, nsid, &state->cookie);
l->l_audit_any_plt |= state->bindflags != 0;
}
afct = afct->next;
}
}
void
_dl_audit_objclose (struct link_map *l)
{
if (__glibc_likely (GLRO(dl_naudit) == 0)
|| GL(dl_ns)[l->l_ns]._ns_loaded->l_auditing)
return;
struct audit_ifaces *afct = GLRO(dl_audit);
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->objclose != NULL)
{
struct auditstate *state= link_map_audit_state (l, cnt);
/* Return value is ignored. */
afct->objclose (&state->cookie);
}
afct = afct->next;
}
}
void
_dl_audit_symbind_alt (struct link_map *l, const ElfW(Sym) *ref, void **value,
lookup_t result)
{
if ((l->l_audit_any_plt | result->l_audit_any_plt) == 0)
return;
const char *strtab = (const char *) D_PTR (result, l_info[DT_STRTAB]);
/* Compute index of the symbol entry in the symbol table of the DSO with
the definition. */
unsigned int ndx = (ref - (ElfW(Sym) *) D_PTR (result, l_info[DT_SYMTAB]));
unsigned int altvalue = 0;
/* Synthesize a symbol record where the st_value field is the result. */
ElfW(Sym) sym = *ref;
sym.st_value = (ElfW(Addr)) *value;
struct audit_ifaces *afct = GLRO(dl_audit);
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
struct auditstate *match_audit = link_map_audit_state (l, cnt);
struct auditstate *result_audit = link_map_audit_state (result, cnt);
if (afct->symbind != NULL
&& ((match_audit->bindflags & LA_FLG_BINDFROM) != 0
|| ((result_audit->bindflags & LA_FLG_BINDTO)
!= 0)))
{
unsigned int flags = altvalue | LA_SYMB_DLSYM;
uintptr_t new_value = afct->symbind (&sym, ndx,
&match_audit->cookie,
&result_audit->cookie,
&flags, strtab + ref->st_name);
if (new_value != (uintptr_t) sym.st_value)
{
altvalue = LA_SYMB_ALTVALUE;
sym.st_value = new_value;
}
afct = afct->next;
}
*value = (void *) sym.st_value;
}
}
rtld_hidden_def (_dl_audit_symbind_alt)
void
_dl_audit_symbind (struct link_map *l, struct reloc_result *reloc_result,
const ElfW(Sym) *defsym, DL_FIXUP_VALUE_TYPE *value,
lookup_t result)
{
reloc_result->bound = result;
/* Compute index of the symbol entry in the symbol table of the DSO with the
definition. */
reloc_result->boundndx = (defsym - (ElfW(Sym) *) D_PTR (result,
l_info[DT_SYMTAB]));
if ((l->l_audit_any_plt | result->l_audit_any_plt) == 0)
{
/* Set all bits since this symbol binding is not interesting. */
reloc_result->enterexit = (1u << DL_NNS) - 1;
return;
}
/* Synthesize a symbol record where the st_value field is the result. */
ElfW(Sym) sym = *defsym;
sym.st_value = DL_FIXUP_VALUE_ADDR (*value);
/* Keep track whether there is any interest in tracing the call in the lower
two bits. */
assert (DL_NNS * 2 <= sizeof (reloc_result->flags) * 8);
assert ((LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT) == 3);
reloc_result->enterexit = LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT;
const char *strtab2 = (const void *) D_PTR (result, l_info[DT_STRTAB]);
unsigned int flags = 0;
struct audit_ifaces *afct = GLRO(dl_audit);
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
/* XXX Check whether both DSOs must request action or only one */
struct auditstate *l_state = link_map_audit_state (l, cnt);
struct auditstate *result_state = link_map_audit_state (result, cnt);
if ((l_state->bindflags & LA_FLG_BINDFROM) != 0
&& (result_state->bindflags & LA_FLG_BINDTO) != 0)
{
if (afct->symbind != NULL)
{
uintptr_t new_value = afct->symbind (&sym,
reloc_result->boundndx,
&l_state->cookie,
&result_state->cookie,
&flags,
strtab2 + defsym->st_name);
if (new_value != (uintptr_t) sym.st_value)
{
flags |= LA_SYMB_ALTVALUE;
sym.st_value = new_value;
}
}
/* Remember the results for every audit library and store a summary
in the first two bits. */
reloc_result->enterexit &= flags & (LA_SYMB_NOPLTENTER
| LA_SYMB_NOPLTEXIT);
reloc_result->enterexit |= ((flags & (LA_SYMB_NOPLTENTER
| LA_SYMB_NOPLTEXIT))
<< ((cnt + 1) * 2));
}
else
/* If the bind flags say this auditor is not interested, set the bits
manually. */
reloc_result->enterexit |= ((LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT)
<< ((cnt + 1) * 2));
afct = afct->next;
}
reloc_result->flags = flags;
*value = DL_FIXUP_ADDR_VALUE (sym.st_value);
}
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