diff mbox series

[v4] elf: Also try DT_RUNPATH for LD_AUDIT dlopen [BZ #28455]

Message ID 20211216020605.792222-1-hjl.tools@gmail.com
State Superseded
Delegated to: Adhemerval Zanella Netto
Headers
Series [v4] elf: Also try DT_RUNPATH for LD_AUDIT dlopen [BZ #28455] |

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

H.J. Lu Dec. 16, 2021, 2:06 a.m. UTC 
  Changes in v4:

1. Move the RUNPATH search for LD_AUDIT dlopen after the other RUNPATH
search
2. Split one test per line and sort.

DT_RUNPATH is only used to find the immediate dependencies of the
executable or shared object containing the DT_RUNPATH entry.  Update
LD_AUDIT dlopen call to try the DT_RUNPATH entry of the executable.
This partially fixes BZ #28455.
---
 elf/Makefile       | 20 +++++++++++++++++---
 elf/dl-load.c      | 37 ++++++++++++++++++++++++++++++++-----
 elf/tst-audit14a.c |  1 +
 3 files changed, 50 insertions(+), 8 deletions(-)
 create mode 100644 elf/tst-audit14a.c

Comments

Adhemerval Zanella Jan. 3, 2022, 8:41 p.m. UTC | #1 
On 15/12/2021 23:06, H.J. Lu via Libc-alpha wrote:
> Changes in v4:
> 
> 1. Move the RUNPATH search for LD_AUDIT dlopen after the other RUNPATH
> search
> 2. Split one test per line and sort.
> 
> DT_RUNPATH is only used to find the immediate dependencies of the
> executable or shared object containing the DT_RUNPATH entry.  Update
> LD_AUDIT dlopen call to try the DT_RUNPATH entry of the executable.
> This partially fixes BZ #28455.

LGTM, I have only a question below.

> ---
>  elf/Makefile       | 20 +++++++++++++++++---
>  elf/dl-load.c      | 37 ++++++++++++++++++++++++++++++++-----
>  elf/tst-audit14a.c |  1 +
>  3 files changed, 50 insertions(+), 8 deletions(-)
>  create mode 100644 elf/tst-audit14a.c
> 
> diff --git a/elf/Makefile b/elf/Makefile
> index fe42caeb0e..625b1a023f 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -249,10 +249,19 @@ ifneq ($(selinux-enabled),1)
>  tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog
>  endif
>  ifeq ($(have-depaudit),yes)
> -tests += tst-audit14 tst-audit15 tst-audit16
> +tests += \
> +  tst-audit14 \
> +  tst-audit14a \
> +  tst-audit15 \
> +  tst-audit16 \
> +
>  ifeq ($(run-built-tests),yes)
> -tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \
> -		 $(objpfx)tst-audit16-cmp.out
> +tests-special += \
> +  $(objpfx)tst-audit14-cmp.out \
> +  $(objpfx)tst-audit14a-cmp.out \
> +  $(objpfx)tst-audit15-cmp.out \
> +  $(objpfx)tst-audit16-cmp.out \
> +
>  endif
>  endif
>  endif

Ok.

> @@ -1529,6 +1538,8 @@ tst-auditmany-ENV = \
>  LDFLAGS-tst-audit14 = -Wl,--audit=tst-auditlogmod-1.so
>  $(objpfx)tst-auditlogmod-1.so: $(libsupport)
>  $(objpfx)tst-audit14.out: $(objpfx)tst-auditlogmod-1.so
> +LDFLAGS-tst-audit14a = -Wl,--audit=tst-auditlogmod-1.so,--enable-new-dtags
> +$(objpfx)tst-audit14a.out: $(objpfx)tst-auditlogmod-1.so
>  LDFLAGS-tst-audit15 = \
>    -Wl,--audit=tst-auditlogmod-1.so,--depaudit=tst-auditlogmod-2.so
>  $(objpfx)tst-auditlogmod-2.so: $(libsupport)
> @@ -1555,6 +1566,9 @@ tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so
>  $(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out
>  	cmp $^ > $@; \
>  	$(evaluate-test)
> +$(objpfx)tst-audit14a-cmp.out: tst-audit14.exp $(objpfx)tst-audit14a.out
> +	cmp $^ > $@; \
> +	$(evaluate-test)
>  $(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out
>  	cmp $^ > $@; \
>  	$(evaluate-test)

Ok.

> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index 721593135e..1c90801903 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -2143,14 +2143,16 @@ _dl_map_object (struct link_map *loader, const char *name,
>  
>        fd = -1;
>  
> +      struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
> +      bool did_main_map;
> +
>        /* When the object has the RUNPATH information we don't use any
>  	 RPATHs.  */
>        if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL)
>  	{
>  	  /* This is the executable's map (if there is one).  Make sure that
>  	     we do not look at it twice.  */
> -	  struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
> -	  bool did_main_map = false;
> +	  did_main_map = false;
>  
>  	  /* First try the DT_RPATH of the dependent object that caused NAME
>  	     to be loaded.  Then that object's dependent, and on up.  */
> @@ -2186,13 +2188,38 @@ _dl_map_object (struct link_map *loader, const char *name,
>  			loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded,
>  			LA_SER_LIBPATH, &found_other_class);
>  
> +      /* Make sure that we do not look at RUNPATH in the executable
> +	 twice.  */
> +      did_main_map = false;
> +
>        /* Look at the RUNPATH information for this binary.  */
>        if (fd == -1 && loader != NULL
>  	  && cache_rpath (loader, &loader->l_runpath_dirs,
>  			  DT_RUNPATH, "RUNPATH"))
> -	fd = open_path (name, namelen, mode,
> -			&loader->l_runpath_dirs, &realname, &fb, loader,
> -			LA_SER_RUNPATH, &found_other_class);
> +	{
> +	  did_main_map = loader == main_map;
> +	  fd = open_path (name, namelen, mode,
> +			  &loader->l_runpath_dirs, &realname, &fb, loader,
> +			  LA_SER_RUNPATH, &found_other_class);
> +	}
> +
> +      /* When processing the lookup we may need to additionally try
> +	 DT_RUNPATH in the executable for a glibc internal dlopen call
> +	 when looking for audit modules.  */
> +      if (__glibc_unlikely (mode & __RTLD_AUDIT)
> +	  && fd == -1
> +	  && !did_main_map
> +	  && main_map != NULL

When main_map would be NULL? For namespaces different than LM_ID_BASE it
does make sense, but I think it is assumed in a lot of places that
for LM_ID_BASE that _ns_loaded is always non-NULL (even for static
linking dl-support guarantees it).

> +	  && main_map->l_type != lt_loaded)
> +	{
> +	  struct r_search_path_struct l_rpath_dirs;
> +	  l_rpath_dirs.dirs = NULL;
> +	  if (cache_rpath (main_map, &l_rpath_dirs,
> +			   DT_RUNPATH, "RUNPATH"))
> +	    fd = open_path (name, namelen, mode, &l_rpath_dirs,
> +			    &realname, &fb, loader ?: main_map,
> +			    LA_SER_RUNPATH, &found_other_class);
> +	}
>  
>        if (fd == -1)
>          {
> diff --git a/elf/tst-audit14a.c b/elf/tst-audit14a.c
> new file mode 100644
> index 0000000000..c6232eacf2
> --- /dev/null
> +++ b/elf/tst-audit14a.c
> @@ -0,0 +1 @@
> +#include "tst-audit14.c"

Add a comment that it checks the -Wl,--enable-new-dtags. Should we also
enforce --disable-new-dtags for tst-audit14 ?
H.J. Lu Jan. 4, 2022, 12:01 a.m. UTC | #2 
On Mon, Jan 3, 2022 at 12:41 PM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
>
>
> On 15/12/2021 23:06, H.J. Lu via Libc-alpha wrote:
> > Changes in v4:
> >
> > 1. Move the RUNPATH search for LD_AUDIT dlopen after the other RUNPATH
> > search
> > 2. Split one test per line and sort.
> >
> > DT_RUNPATH is only used to find the immediate dependencies of the
> > executable or shared object containing the DT_RUNPATH entry.  Update
> > LD_AUDIT dlopen call to try the DT_RUNPATH entry of the executable.
> > This partially fixes BZ #28455.
>
> LGTM, I have only a question below.
>
> > ---
> >  elf/Makefile       | 20 +++++++++++++++++---
> >  elf/dl-load.c      | 37 ++++++++++++++++++++++++++++++++-----
> >  elf/tst-audit14a.c |  1 +
> >  3 files changed, 50 insertions(+), 8 deletions(-)
> >  create mode 100644 elf/tst-audit14a.c
> >
> > diff --git a/elf/Makefile b/elf/Makefile
> > index fe42caeb0e..625b1a023f 100644
> > --- a/elf/Makefile
> > +++ b/elf/Makefile
> > @@ -249,10 +249,19 @@ ifneq ($(selinux-enabled),1)
> >  tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog
> >  endif
> >  ifeq ($(have-depaudit),yes)
> > -tests += tst-audit14 tst-audit15 tst-audit16
> > +tests += \
> > +  tst-audit14 \
> > +  tst-audit14a \
> > +  tst-audit15 \
> > +  tst-audit16 \
> > +
> >  ifeq ($(run-built-tests),yes)
> > -tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \
> > -              $(objpfx)tst-audit16-cmp.out
> > +tests-special += \
> > +  $(objpfx)tst-audit14-cmp.out \
> > +  $(objpfx)tst-audit14a-cmp.out \
> > +  $(objpfx)tst-audit15-cmp.out \
> > +  $(objpfx)tst-audit16-cmp.out \
> > +
> >  endif
> >  endif
> >  endif
>
> Ok.
>
> > @@ -1529,6 +1538,8 @@ tst-auditmany-ENV = \
> >  LDFLAGS-tst-audit14 = -Wl,--audit=tst-auditlogmod-1.so
> >  $(objpfx)tst-auditlogmod-1.so: $(libsupport)
> >  $(objpfx)tst-audit14.out: $(objpfx)tst-auditlogmod-1.so
> > +LDFLAGS-tst-audit14a = -Wl,--audit=tst-auditlogmod-1.so,--enable-new-dtags
> > +$(objpfx)tst-audit14a.out: $(objpfx)tst-auditlogmod-1.so
> >  LDFLAGS-tst-audit15 = \
> >    -Wl,--audit=tst-auditlogmod-1.so,--depaudit=tst-auditlogmod-2.so
> >  $(objpfx)tst-auditlogmod-2.so: $(libsupport)
> > @@ -1555,6 +1566,9 @@ tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so
> >  $(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out
> >       cmp $^ > $@; \
> >       $(evaluate-test)
> > +$(objpfx)tst-audit14a-cmp.out: tst-audit14.exp $(objpfx)tst-audit14a.out
> > +     cmp $^ > $@; \
> > +     $(evaluate-test)
> >  $(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out
> >       cmp $^ > $@; \
> >       $(evaluate-test)
>
> Ok.
>
> > diff --git a/elf/dl-load.c b/elf/dl-load.c
> > index 721593135e..1c90801903 100644
> > --- a/elf/dl-load.c
> > +++ b/elf/dl-load.c
> > @@ -2143,14 +2143,16 @@ _dl_map_object (struct link_map *loader, const char *name,
> >
> >        fd = -1;
> >
> > +      struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
> > +      bool did_main_map;
> > +
> >        /* When the object has the RUNPATH information we don't use any
> >        RPATHs.  */
> >        if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL)
> >       {
> >         /* This is the executable's map (if there is one).  Make sure that
> >            we do not look at it twice.  */
> > -       struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
> > -       bool did_main_map = false;
> > +       did_main_map = false;
> >
> >         /* First try the DT_RPATH of the dependent object that caused NAME
> >            to be loaded.  Then that object's dependent, and on up.  */
> > @@ -2186,13 +2188,38 @@ _dl_map_object (struct link_map *loader, const char *name,
> >                       loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded,
> >                       LA_SER_LIBPATH, &found_other_class);
> >
> > +      /* Make sure that we do not look at RUNPATH in the executable
> > +      twice.  */
> > +      did_main_map = false;
> > +
> >        /* Look at the RUNPATH information for this binary.  */
> >        if (fd == -1 && loader != NULL
> >         && cache_rpath (loader, &loader->l_runpath_dirs,
> >                         DT_RUNPATH, "RUNPATH"))
> > -     fd = open_path (name, namelen, mode,
> > -                     &loader->l_runpath_dirs, &realname, &fb, loader,
> > -                     LA_SER_RUNPATH, &found_other_class);
> > +     {
> > +       did_main_map = loader == main_map;
> > +       fd = open_path (name, namelen, mode,
> > +                       &loader->l_runpath_dirs, &realname, &fb, loader,
> > +                       LA_SER_RUNPATH, &found_other_class);
> > +     }
> > +
> > +      /* When processing the lookup we may need to additionally try
> > +      DT_RUNPATH in the executable for a glibc internal dlopen call
> > +      when looking for audit modules.  */
> > +      if (__glibc_unlikely (mode & __RTLD_AUDIT)
> > +       && fd == -1
> > +       && !did_main_map
> > +       && main_map != NULL
>
> When main_map would be NULL? For namespaces different than LM_ID_BASE it
> does make sense, but I think it is assumed in a lot of places that
> for LM_ID_BASE that _ns_loaded is always non-NULL (even for static
> linking dl-support guarantees it).

I simplified it in the v5 patch.  But I kept the main_map check since it is
also checked for DT_RPATH in the executable.

> > +       && main_map->l_type != lt_loaded)
> > +     {
> > +       struct r_search_path_struct l_rpath_dirs;
> > +       l_rpath_dirs.dirs = NULL;
> > +       if (cache_rpath (main_map, &l_rpath_dirs,
> > +                        DT_RUNPATH, "RUNPATH"))
> > +         fd = open_path (name, namelen, mode, &l_rpath_dirs,
> > +                         &realname, &fb, loader ?: main_map,
> > +                         LA_SER_RUNPATH, &found_other_class);
> > +     }
> >
> >        if (fd == -1)
> >          {
> > diff --git a/elf/tst-audit14a.c b/elf/tst-audit14a.c
> > new file mode 100644
> > index 0000000000..c6232eacf2
> > --- /dev/null
> > +++ b/elf/tst-audit14a.c
> > @@ -0,0 +1 @@
> > +#include "tst-audit14.c"
>
> Add a comment that it checks the -Wl,--enable-new-dtags. Should we also
> enforce --disable-new-dtags for tst-audit14 ?

Fixed in the v5:

https://patchwork.sourceware.org/project/glibc/patch/20220103235753.2062518-2-hjl.tools@gmail.com/

Thanks.
diff mbox series

Patch

diff --git a/elf/Makefile b/elf/Makefile
index fe42caeb0e..625b1a023f 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -249,10 +249,19 @@  ifneq ($(selinux-enabled),1)
 tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog
 endif
 ifeq ($(have-depaudit),yes)
-tests += tst-audit14 tst-audit15 tst-audit16
+tests += \
+  tst-audit14 \
+  tst-audit14a \
+  tst-audit15 \
+  tst-audit16 \
+
 ifeq ($(run-built-tests),yes)
-tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \
-		 $(objpfx)tst-audit16-cmp.out
+tests-special += \
+  $(objpfx)tst-audit14-cmp.out \
+  $(objpfx)tst-audit14a-cmp.out \
+  $(objpfx)tst-audit15-cmp.out \
+  $(objpfx)tst-audit16-cmp.out \
+
 endif
 endif
 endif
@@ -1529,6 +1538,8 @@  tst-auditmany-ENV = \
 LDFLAGS-tst-audit14 = -Wl,--audit=tst-auditlogmod-1.so
 $(objpfx)tst-auditlogmod-1.so: $(libsupport)
 $(objpfx)tst-audit14.out: $(objpfx)tst-auditlogmod-1.so
+LDFLAGS-tst-audit14a = -Wl,--audit=tst-auditlogmod-1.so,--enable-new-dtags
+$(objpfx)tst-audit14a.out: $(objpfx)tst-auditlogmod-1.so
 LDFLAGS-tst-audit15 = \
   -Wl,--audit=tst-auditlogmod-1.so,--depaudit=tst-auditlogmod-2.so
 $(objpfx)tst-auditlogmod-2.so: $(libsupport)
@@ -1555,6 +1566,9 @@  tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so
 $(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out
 	cmp $^ > $@; \
 	$(evaluate-test)
+$(objpfx)tst-audit14a-cmp.out: tst-audit14.exp $(objpfx)tst-audit14a.out
+	cmp $^ > $@; \
+	$(evaluate-test)
 $(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out
 	cmp $^ > $@; \
 	$(evaluate-test)
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 721593135e..1c90801903 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -2143,14 +2143,16 @@  _dl_map_object (struct link_map *loader, const char *name,
 
       fd = -1;
 
+      struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
+      bool did_main_map;
+
       /* When the object has the RUNPATH information we don't use any
 	 RPATHs.  */
       if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL)
 	{
 	  /* This is the executable's map (if there is one).  Make sure that
 	     we do not look at it twice.  */
-	  struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
-	  bool did_main_map = false;
+	  did_main_map = false;
 
 	  /* First try the DT_RPATH of the dependent object that caused NAME
 	     to be loaded.  Then that object's dependent, and on up.  */
@@ -2186,13 +2188,38 @@  _dl_map_object (struct link_map *loader, const char *name,
 			loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded,
 			LA_SER_LIBPATH, &found_other_class);
 
+      /* Make sure that we do not look at RUNPATH in the executable
+	 twice.  */
+      did_main_map = false;
+
       /* Look at the RUNPATH information for this binary.  */
       if (fd == -1 && loader != NULL
 	  && cache_rpath (loader, &loader->l_runpath_dirs,
 			  DT_RUNPATH, "RUNPATH"))
-	fd = open_path (name, namelen, mode,
-			&loader->l_runpath_dirs, &realname, &fb, loader,
-			LA_SER_RUNPATH, &found_other_class);
+	{
+	  did_main_map = loader == main_map;
+	  fd = open_path (name, namelen, mode,
+			  &loader->l_runpath_dirs, &realname, &fb, loader,
+			  LA_SER_RUNPATH, &found_other_class);
+	}
+
+      /* When processing the lookup we may need to additionally try
+	 DT_RUNPATH in the executable for a glibc internal dlopen call
+	 when looking for audit modules.  */
+      if (__glibc_unlikely (mode & __RTLD_AUDIT)
+	  && fd == -1
+	  && !did_main_map
+	  && main_map != NULL
+	  && main_map->l_type != lt_loaded)
+	{
+	  struct r_search_path_struct l_rpath_dirs;
+	  l_rpath_dirs.dirs = NULL;
+	  if (cache_rpath (main_map, &l_rpath_dirs,
+			   DT_RUNPATH, "RUNPATH"))
+	    fd = open_path (name, namelen, mode, &l_rpath_dirs,
+			    &realname, &fb, loader ?: main_map,
+			    LA_SER_RUNPATH, &found_other_class);
+	}
 
       if (fd == -1)
         {
diff --git a/elf/tst-audit14a.c b/elf/tst-audit14a.c
new file mode 100644
index 0000000000..c6232eacf2
--- /dev/null
+++ b/elf/tst-audit14a.c
@@ -0,0 +1 @@ 
+#include "tst-audit14.c"