diff mbox series

hppa: Fix bind-now audit (BZ #28857)

Message ID 20220204200853.2799635-1-adhemerval.zanella@linaro.org
State Superseded
Headers
Series hppa: Fix bind-now audit (BZ #28857) |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit success Build for i686

Commit Message

Adhemerval Zanella Netto Feb. 4, 2022, 8:08 p.m. UTC 
  On hppa, a function pointer returned by la_symbind is actually a function
descriptor has the plabel bit set (bit 30).  This must be cleared to get
the actual address of the descriptor.  If the descriptor has been bound,
the first word of the descriptor is the physical address of theA function,
otherwise, the first word of the descriptor points to a trampoline in the
PLT.

This is handle already by '_dl_lookup_address', so it is used on
DL_FIXUP_BINDNOW_RELOC to setup the instruction pointer in the
relocation address.

This patch also adds a workaround on tests because on hppa (and it seems
to be the only ABI I have see it), some shared library adds a dynamic PLT
relocation to am empty symbol name:

$ readelf -r elf/tst-audit25mod1.so
[...]
Relocation section '.rela.plt' at offset 0x464 contains 6 entries:
 Offset     Info    Type            Sym.Value  Sym. Name + Addend
00002008  00000081 R_PARISC_IPLT                508
[...]

It breaks some assumptions on the test, where a symbol with an empty
name ("") is passed on la_symbind.

Checked on x86_64-linux-gnu and hppa-linux-gnu.
---
 elf/Makefile                | 2 +-
 elf/dl-audit.c              | 3 ++-
 elf/tst-auditmod24a.c       | 4 +++-
 elf/tst-auditmod24d.c       | 4 +++-
 elf/tst-auditmod25.c        | 2 +-
 sysdeps/hppa/dl-fptr.c      | 1 +
 sysdeps/hppa/dl-lookupcfg.h | 8 ++++++--
 7 files changed, 17 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/elf/Makefile b/elf/Makefile
index 5bdf0a383d..7372cb191c 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -2210,7 +2210,7 @@  $(objpfx)tst-audit24c.out: $(objpfx)tst-auditmod24c.so
 $(objpfx)tst-audit24c: $(objpfx)tst-audit24amod1.so \
 		       $(objpfx)tst-audit24amod2.so
 tst-audit24c-ENV = LD_BIND_NOW=1 LD_AUDIT=$(objpfx)tst-auditmod24c.so
-LDFLAGS-tst-audit24b = -Wl,-z,lazy
+LDFLAGS-tst-audit24c = -Wl,-z,lazy
 
 $(objpfx)tst-audit24d.out: $(objpfx)tst-auditmod24d.so
 $(objpfx)tst-audit24d: $(objpfx)tst-audit24dmod1.so \
diff --git a/elf/dl-audit.c b/elf/dl-audit.c
index 794bfd45cd..efc0492474 100644
--- a/elf/dl-audit.c
+++ b/elf/dl-audit.c
@@ -257,7 +257,8 @@  _dl_audit_symbind (struct link_map *l, struct reloc_result *reloc_result,
       reloc_result->flags = flags;
     }
 
-  DL_FIXUP_BINDNOW_RELOC (value, new_value, sym.st_value);
+  if (flags & LA_SYMB_ALTVALUE)
+    DL_FIXUP_BINDNOW_RELOC (value, new_value, sym.st_value);
 }
 
 void
diff --git a/elf/tst-auditmod24a.c b/elf/tst-auditmod24a.c
index d8e88f3984..3075dfae2f 100644
--- a/elf/tst-auditmod24a.c
+++ b/elf/tst-auditmod24a.c
@@ -110,5 +110,7 @@  la_symbind32 (Elf32_Sym *sym, unsigned int ndx,
       return sym->st_value;
     }
 
-  abort ();
+  if (symname[0] != '\0')
+    abort ();
+  return sym->st_value;
 }
diff --git a/elf/tst-auditmod24d.c b/elf/tst-auditmod24d.c
index 8c803ecc0a..badc6be451 100644
--- a/elf/tst-auditmod24d.c
+++ b/elf/tst-auditmod24d.c
@@ -116,5 +116,7 @@  la_symbind32 (Elf32_Sym *sym, unsigned int ndx,
 	}
     }
 
-  abort ();
+  if (symname[0] != '\0')
+    abort ();
+  return sym->st_value;
 }
diff --git a/elf/tst-auditmod25.c b/elf/tst-auditmod25.c
index 526f5c54bc..20640a8daf 100644
--- a/elf/tst-auditmod25.c
+++ b/elf/tst-auditmod25.c
@@ -72,7 +72,7 @@  la_symbind32 (Elf32_Sym *sym, unsigned int ndx,
 	      unsigned int *flags, const char *symname)
 #endif
 {
-  if (*refcook != -1 && *defcook != -1)
+  if (*refcook != -1 && *defcook != -1 && symname[0] != '\0')
     fprintf (stderr, "la_symbind: %s %u\n", symname,
 	     *flags & (LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT) ? 1 : 0);
   return sym->st_value;
diff --git a/sysdeps/hppa/dl-fptr.c b/sysdeps/hppa/dl-fptr.c
index 2584557c4f..4cc2cb21b1 100644
--- a/sysdeps/hppa/dl-fptr.c
+++ b/sysdeps/hppa/dl-fptr.c
@@ -407,3 +407,4 @@  _dl_lookup_address (const void *address)
 
   return (ElfW(Addr)) desc[0];
 }
+rtld_hidden_def (_dl_lookup_address)
diff --git a/sysdeps/hppa/dl-lookupcfg.h b/sysdeps/hppa/dl-lookupcfg.h
index 8da2412fea..3929fc84ae 100644
--- a/sysdeps/hppa/dl-lookupcfg.h
+++ b/sysdeps/hppa/dl-lookupcfg.h
@@ -30,6 +30,7 @@  rtld_hidden_proto (_dl_symbol_address)
 #define DL_SYMBOL_ADDRESS(map, ref) _dl_symbol_address(map, ref)
 
 Elf32_Addr _dl_lookup_address (const void *address);
+rtld_hidden_proto (_dl_lookup_address)
 
 #define DL_LOOKUP_ADDRESS(addr) _dl_lookup_address ((const void *) addr)
 
@@ -81,5 +82,8 @@  void attribute_hidden _dl_unmap (struct link_map *map);
 #define DL_FIXUP_VALUE_ADDR(value) ((uintptr_t) &(value))
 #define DL_FIXUP_ADDR_VALUE(addr) (*(struct fdesc *) (addr))
 #define DL_FIXUP_BINDNOW_ADDR_VALUE(addr) (addr)
-#define DL_FIXUP_BINDNOW_RELOC(value, new_value, st_value) \
-  (*value) = *(struct fdesc *) (st_value)
+#define DL_FIXUP_BINDNOW_RELOC(value, new_value, st_value)	\
+  ({								\
+     value->ip = _dl_lookup_address ((void *) new_value);	\
+     value->gp = ((struct fdesc *) (new_value))->gp;		\
+  })