* [PATCH] Fix getting return address in elf/tst-audit28.c.
@ 2023-07-13 13:13 Stefan Liebler
2023-07-19 7:06 ` Stefan Liebler
2023-07-19 9:15 ` Florian Weimer
0 siblings, 2 replies; 4+ messages in thread
From: Stefan Liebler @ 2023-07-13 13:13 UTC (permalink / raw)
To: libc-alpha; +Cc: fweimer, Stefan Liebler
Starting with commit 1bcfe0f732066ae5336b252295591ebe7e51c301, the
test was enhanced and the object for __builtin_return_address (0)
is searched with _dl_find_object.
Unfortunately on e.g. s390 (31bit), a postprocessing step is needed
as the highest bit has to be masked out. This can be done with
__builtin_extract_return_addr.
Without this postprocessing, _dl_find_object returns with -1 and the
content of dlfo is invalid, which may lead to segfaults in basename.
Therefore those checks are now only done on success.
---
elf/tst-auditmod28.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/elf/tst-auditmod28.c b/elf/tst-auditmod28.c
index f6dfbbe202..35180208ba 100644
--- a/elf/tst-auditmod28.c
+++ b/elf/tst-auditmod28.c
@@ -73,12 +73,19 @@ la_version (unsigned int current)
/* Check _dl_find_object. */
struct dl_find_object dlfo;
- TEST_COMPARE (_dl_find_object (__builtin_return_address (0), &dlfo), 0);
- /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */
- if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0)
- TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO);
- TEST_COMPARE (_dl_find_object (dlsym (handle, "environ"), &dlfo), 0);
- TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO);
+ void *ret_addr = __builtin_extract_return_addr (__builtin_return_address (0));
+ int ret_dl_find_object =_dl_find_object (ret_addr, &dlfo);
+ TEST_COMPARE (ret_dl_find_object, 0);
+ if (ret_dl_find_object == 0)
+ {
+ /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */
+ if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0)
+ TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO);
+ }
+ ret_dl_find_object = _dl_find_object (dlsym (handle, "environ"), &dlfo);
+ TEST_COMPARE (ret_dl_find_object, 0);
+ if (ret_dl_find_object == 0)
+ TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO);
TEST_COMPARE (_dl_find_object ((void *) 1, &dlfo), -1);
TEST_COMPARE (_dl_find_object ((void *) -1, &dlfo), -1);
--
2.41.0
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Fix getting return address in elf/tst-audit28.c.
2023-07-13 13:13 [PATCH] Fix getting return address in elf/tst-audit28.c Stefan Liebler
@ 2023-07-19 7:06 ` Stefan Liebler
2023-07-19 9:15 ` Florian Weimer
1 sibling, 0 replies; 4+ messages in thread
From: Stefan Liebler @ 2023-07-19 7:06 UTC (permalink / raw)
To: libc-alpha; +Cc: fweimer
Ping
On 13.07.23 15:13, Stefan Liebler wrote:
> Starting with commit 1bcfe0f732066ae5336b252295591ebe7e51c301, the
> test was enhanced and the object for __builtin_return_address (0)
> is searched with _dl_find_object.
>
> Unfortunately on e.g. s390 (31bit), a postprocessing step is needed
> as the highest bit has to be masked out. This can be done with
> __builtin_extract_return_addr.
>
> Without this postprocessing, _dl_find_object returns with -1 and the
> content of dlfo is invalid, which may lead to segfaults in basename.
> Therefore those checks are now only done on success.
> ---
> elf/tst-auditmod28.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/elf/tst-auditmod28.c b/elf/tst-auditmod28.c
> index f6dfbbe202..35180208ba 100644
> --- a/elf/tst-auditmod28.c
> +++ b/elf/tst-auditmod28.c
> @@ -73,12 +73,19 @@ la_version (unsigned int current)
>
> /* Check _dl_find_object. */
> struct dl_find_object dlfo;
> - TEST_COMPARE (_dl_find_object (__builtin_return_address (0), &dlfo), 0);
> - /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */
> - if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0)
> - TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO);
> - TEST_COMPARE (_dl_find_object (dlsym (handle, "environ"), &dlfo), 0);
> - TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO);
> + void *ret_addr = __builtin_extract_return_addr (__builtin_return_address (0));
> + int ret_dl_find_object =_dl_find_object (ret_addr, &dlfo);
> + TEST_COMPARE (ret_dl_find_object, 0);
> + if (ret_dl_find_object == 0)
> + {
> + /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */
> + if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0)
> + TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO);
> + }
> + ret_dl_find_object = _dl_find_object (dlsym (handle, "environ"), &dlfo);
> + TEST_COMPARE (ret_dl_find_object, 0);
> + if (ret_dl_find_object == 0)
> + TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO);
> TEST_COMPARE (_dl_find_object ((void *) 1, &dlfo), -1);
> TEST_COMPARE (_dl_find_object ((void *) -1, &dlfo), -1);
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Fix getting return address in elf/tst-audit28.c.
2023-07-13 13:13 [PATCH] Fix getting return address in elf/tst-audit28.c Stefan Liebler
2023-07-19 7:06 ` Stefan Liebler
@ 2023-07-19 9:15 ` Florian Weimer
2023-07-19 11:20 ` Stefan Liebler
1 sibling, 1 reply; 4+ messages in thread
From: Florian Weimer @ 2023-07-19 9:15 UTC (permalink / raw)
To: Stefan Liebler; +Cc: libc-alpha
* Stefan Liebler:
> Starting with commit 1bcfe0f732066ae5336b252295591ebe7e51c301, the
> test was enhanced and the object for __builtin_return_address (0)
> is searched with _dl_find_object.
>
> Unfortunately on e.g. s390 (31bit), a postprocessing step is needed
> as the highest bit has to be masked out. This can be done with
> __builtin_extract_return_addr.
>
> Without this postprocessing, _dl_find_object returns with -1 and the
> content of dlfo is invalid, which may lead to segfaults in basename.
> Therefore those checks are now only done on success.
> ---
> elf/tst-auditmod28.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/elf/tst-auditmod28.c b/elf/tst-auditmod28.c
> index f6dfbbe202..35180208ba 100644
> --- a/elf/tst-auditmod28.c
> +++ b/elf/tst-auditmod28.c
> @@ -73,12 +73,19 @@ la_version (unsigned int current)
>
> /* Check _dl_find_object. */
> struct dl_find_object dlfo;
> - TEST_COMPARE (_dl_find_object (__builtin_return_address (0), &dlfo), 0);
> - /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */
> - if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0)
> - TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO);
> - TEST_COMPARE (_dl_find_object (dlsym (handle, "environ"), &dlfo), 0);
> - TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO);
> + void *ret_addr = __builtin_extract_return_addr (__builtin_return_address (0));
> + int ret_dl_find_object =_dl_find_object (ret_addr, &dlfo);
> + TEST_COMPARE (ret_dl_find_object, 0);
> + if (ret_dl_find_object == 0)
> + {
> + /* "ld.so" is seen with --enable-hardcoded-path-in-tests. */
> + if (strcmp (basename (dlfo.dlfo_link_map->l_name), "ld.so") != 0)
> + TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LD_SO);
> + }
> + ret_dl_find_object = _dl_find_object (dlsym (handle, "environ"), &dlfo);
> + TEST_COMPARE (ret_dl_find_object, 0);
> + if (ret_dl_find_object == 0)
> + TEST_COMPARE_STRING (basename (dlfo.dlfo_link_map->l_name), LIBC_SO);
> TEST_COMPARE (_dl_find_object ((void *) 1, &dlfo), -1);
> TEST_COMPARE (_dl_find_object ((void *) -1, &dlfo), -1);
Based on the GCC documentation, this should be reasinable portable.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Thanks,
Florian
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-07-13 13:13 [PATCH] Fix getting return address in elf/tst-audit28.c Stefan Liebler
2023-07-19 7:06 ` Stefan Liebler
2023-07-19 9:15 ` Florian Weimer
2023-07-19 11:20 ` Stefan Liebler
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