[v3] hppa: Fix bind-now audit (BZ #28857)
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| dj/TryBot-apply_patch |
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Patch applied to master at the time it was sent
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| dj/TryBot-32bit |
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Build for i686
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Commit Message
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 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.
---
v3: Remove _dl_lookup_address usage.
---
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-lookupcfg.h | 8 +++++---
6 files changed, 15 insertions(+), 8 deletions(-)
Comments
On 2022-02-07 9:15 a.m., Adhemerval Zanella wrote:
> diff --git a/sysdeps/hppa/dl-lookupcfg.h b/sysdeps/hppa/dl-lookupcfg.h
> index 8da2412fea..535177df66 100644
> --- a/sysdeps/hppa/dl-lookupcfg.h
> +++ b/sysdeps/hppa/dl-lookupcfg.h
> @@ -79,7 +79,9 @@ void attribute_hidden _dl_unmap (struct link_map *map);
> /* Extract the code address from a fixup value */
> #define DL_FIXUP_VALUE_CODE_ADDR(value) ((value).ip)
> #define DL_FIXUP_VALUE_ADDR(value) ((uintptr_t) &(value))
> -#define DL_FIXUP_ADDR_VALUE(addr) (*(struct fdesc *) (addr))
> +/* Clear the plabel bit to get the actual address of the descriptor. */
> +#define DL_FIXUP_ADDR_VALUE(addr) \
> + (*(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (addr) & ~2))
> #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) = *(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (new_value) & ~2);
This is okay.
Dave
On Feb 07 2022, Adhemerval Zanella via Libc-alpha wrote:
> +/* Clear the plabel bit to get the actual address of the descriptor. */
> +#define DL_FIXUP_ADDR_VALUE(addr) \
> + (*(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (addr) & ~2))
Why not uintptr_t?
> +#define DL_FIXUP_BINDNOW_RELOC(value, new_value, st_value) \
> + *(value) = *(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (new_value) & ~2);
Likewise. Why is there a semicolon?
On 2022-02-07 10:46 a.m., Andreas Schwab wrote:
> On Feb 07 2022, Adhemerval Zanella via Libc-alpha wrote:
>
>> +/* Clear the plabel bit to get the actual address of the descriptor. */
>> +#define DL_FIXUP_ADDR_VALUE(addr) \
>> + (*(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (addr) & ~2))
> Why not uintptr_t?
>
>> +#define DL_FIXUP_BINDNOW_RELOC(value, new_value, st_value) \
>> + *(value) = *(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (new_value) & ~2);
> Likewise. Why is there a semicolon?
Good suggestions.
@@ -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 \
@@ -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
@@ -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;
}
@@ -116,5 +116,7 @@ la_symbind32 (Elf32_Sym *sym, unsigned int ndx,
}
}
- abort ();
+ if (symname[0] != '\0')
+ abort ();
+ return sym->st_value;
}
@@ -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;
@@ -79,7 +79,9 @@ void attribute_hidden _dl_unmap (struct link_map *map);
/* Extract the code address from a fixup value */
#define DL_FIXUP_VALUE_CODE_ADDR(value) ((value).ip)
#define DL_FIXUP_VALUE_ADDR(value) ((uintptr_t) &(value))
-#define DL_FIXUP_ADDR_VALUE(addr) (*(struct fdesc *) (addr))
+/* Clear the plabel bit to get the actual address of the descriptor. */
+#define DL_FIXUP_ADDR_VALUE(addr) \
+ (*(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (addr) & ~2))
#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) = *(DL_FIXUP_VALUE_TYPE *) ((unsigned int) (new_value) & ~2);