lib/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2025-12-24 17:51:17 +03:00
Code Activity

elf: Add _dl_audit_symbind_alt and _dl_audit_symbind

Browse Source 
It consolidates the code required to call la_symbind{32,64} audit
callback.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
This commit is contained in:
Adhemerval Zanella
2021-07-20 15:58:35 -03:00
parent 311c9ee54e
commit cda4f265c6
5 changed files with 135 additions and 124 deletions
Download Patch File Download Diff File Expand all files Collapse all files

122
elf/dl-audit.c
View File

@@ -16,6 +16,7 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <ldsodefs.h>
void
@@ -106,3 +107,124 @@ _dl_audit_objclose (struct link_map *l)
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);
}