diff mbox series

[v7,05/16] elf: Add _dl_audit_symbind_alt and _dl_audit_symbind

Message ID 20211222132712.523295-6-adhemerval.zanella@linaro.org
State Committed
Commit cda4f265c65fb6c4ce38ca1cf0a7e527c5e77cd5
Headers show
Series Multiple rtld-audit fixes | expand

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Adhemerval Zanella Dec. 22, 2021, 1:27 p.m. UTC
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.
---
 elf/Versions               |   1 +
 elf/dl-audit.c             | 122 +++++++++++++++++++++++++++++++++++++
 elf/dl-runtime.c           |  79 +-----------------------
 elf/dl-sym-post.h          |  47 +-------------
 sysdeps/generic/ldsodefs.h |  10 +++
 5 files changed, 135 insertions(+), 124 deletions(-)

Comments

Florian Weimer Dec. 24, 2021, 12:42 p.m. UTC | #1
* Adhemerval Zanella:

> 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.
> ---
>  elf/Versions               |   1 +
>  elf/dl-audit.c             | 122 +++++++++++++++++++++++++++++++++++++
>  elf/dl-runtime.c           |  79 +-----------------------
>  elf/dl-sym-post.h          |  47 +-------------
>  sysdeps/generic/ldsodefs.h |  10 +++
>  5 files changed, 135 insertions(+), 124 deletions(-)

Looks good to me.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

Thanks,
Florian
diff mbox series

Patch

diff --git a/elf/Versions b/elf/Versions
index 775aab62af..25e91339b5 100644
--- a/elf/Versions
+++ b/elf/Versions
@@ -55,6 +55,7 @@  ld {
     _dl_argv; _dl_find_dso_for_object; _dl_get_tls_static_info;
     _dl_deallocate_tls; _dl_make_stack_executable;
     _dl_rtld_di_serinfo; _dl_starting_up; _dl_fatal_printf;
+    _dl_audit_symbind_alt;
     _rtld_global; _rtld_global_ro;
 
     # Only here for gdb while a better method is developed.
diff --git a/elf/dl-audit.c b/elf/dl-audit.c
index ff04592417..3c1a230af8 100644
--- a/elf/dl-audit.c
+++ b/elf/dl-audit.c
@@ -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
@@ -110,3 +111,124 @@  _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);
+}
diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c
index 61c260ddb8..c4413c9165 100644
--- a/elf/dl-runtime.c
+++ b/elf/dl-runtime.c
@@ -297,84 +297,7 @@  _dl_profile_fixup (
 	 auditing libraries the possibility to change the value and
 	 tell us whether further auditing is wanted.  */
       if (defsym != NULL && GLRO(dl_naudit) > 0)
-	{
-	  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]));
-
-	  /* Determine whether any of the two participating DSOs is
-	     interested in auditing.  */
-	  if ((l->l_audit_any_plt | result->l_audit_any_plt) != 0)
-	    {
-	      unsigned int flags = 0;
-	      struct audit_ifaces *afct = GLRO(dl_audit);
-	      /* 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]);
-
-	      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);
-	    }
-	  else
-	    /* Set all bits since this symbol binding is not interesting.  */
-	    reloc_result->enterexit = (1u << DL_NNS) - 1;
-	}
+	_dl_audit_symbind (l, reloc_result, defsym, &value, result);
 #endif
 
       /* Store the result for later runs.  */
diff --git a/elf/dl-sym-post.h b/elf/dl-sym-post.h
index d68c2d2b1c..a11095d3e8 100644
--- a/elf/dl-sym-post.h
+++ b/elf/dl-sym-post.h
@@ -52,54 +52,9 @@  _dl_sym_post (lookup_t result, const ElfW(Sym) *ref, void *value,
      tell us whether further auditing is wanted.  */
   if (__glibc_unlikely (GLRO(dl_naudit) > 0))
     {
-      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]));
-
       if (match == NULL)
         match = _dl_sym_find_caller_link_map (caller);
-
-      if ((match->l_audit_any_plt | result->l_audit_any_plt) != 0)
-        {
-          unsigned int altvalue = 0;
-          struct audit_ifaces *afct = GLRO(dl_audit);
-          /* Synthesize a symbol record where the st_value field is
-             the result.  */
-          ElfW(Sym) sym = *ref;
-          sym.st_value = (ElfW(Addr)) value;
-
-          for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
-            {
-              struct auditstate *match_audit
-                = link_map_audit_state (match, 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;
-        }
+      _dl_audit_symbind_alt (match, ref, &value, result);
     }
 #endif
   return value;
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 14ae41c535..d312c4c97b 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1421,6 +1421,16 @@  void _dl_audit_objopen (struct link_map *l, Lmid_t nsid)
 /* Call the la_objclose from the audit modules for the link_map L.  */
 void _dl_audit_objclose (struct link_map *l)
   attribute_hidden;
+
+/* Call the la_symbind{32,64} from the audit modules for the link_map L.  */
+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)
+  attribute_hidden;
+/* Same as _dl_audit_symbind, but also sets LA_SYMB_DLSYM flag.  */
+void _dl_audit_symbind_alt (struct link_map *l, const ElfW(Sym) *ref,
+			    void **value, lookup_t result);
+rtld_hidden_proto (_dl_audit_symbind_alt)
 #endif /* SHARED */
 
 #if PTHREAD_IN_LIBC && defined SHARED