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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-04-24 12:27:44 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-04-28 10:13:46 -0300 |
| commit | 0c3425942374e72c3bcac28b2578117d36b0f9df (patch) | |
| tree | 34cc4753eec69109e6ff938b7fd1f5d3cf9b12c2 /sysdeps/unix | |
| parent | 4c966c078036abe0e36bd86c9eaeb4501e552977 (diff) | |
| download | glibc-0c3425942374e72c3bcac28b2578117d36b0f9df.zip glibc-0c3425942374e72c3bcac28b2578117d36b0f9df.tar.gz glibc-0c3425942374e72c3bcac28b2578117d36b0f9df.tar.bz2 | |
nptl: Fix pthread_getattr_np when modules with execstack are allowed (BZ 32897)
The BZ 32653 fix (12a497c716f0a06be5946cabb8c3ec22a079771e) kept the
stack pointer zeroing from make_main_stack_executable on
_dl_make_stack_executable. However, previously the 'stack_endp'
pointed to temporary variable created before the call of
_dl_map_object_from_fd; while now we use the __libc_stack_end
directly.
Since pthread_getattr_np relies on correct __libc_stack_end, if
_dl_make_stack_executable is called (for instance, when
glibc.rtld.execstack=2 is set) __libc_stack_end will be set to zero,
and the call will always fail.
The __libc_stack_end zero was used a mitigation hardening, but since
52a01100ad011293197637e42b5be1a479a2f4ae it is used solely on
pthread_getattr_np code. So there is no point in zeroing anymore.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Sam James <sam@gentoo.org>
Diffstat (limited to 'sysdeps/unix')
| -rw-r--r-- | sysdeps/unix/sysv/linux/dl-execstack.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c index 9791b33..6db9601 100644 --- a/sysdeps/unix/sysv/linux/dl-execstack.c +++ b/sysdeps/unix/sysv/linux/dl-execstack.c @@ -19,10 +19,10 @@ #include <ldsodefs.h> int -_dl_make_stack_executable (void **stack_endp) +_dl_make_stack_executable (const void *stack_endp) { /* This gives us the highest/lowest page that needs to be changed. */ - uintptr_t page = ((uintptr_t) *stack_endp + uintptr_t page = ((uintptr_t) stack_endp & -(intptr_t) GLRO(dl_pagesize)); if (__mprotect ((void *) page, GLRO(dl_pagesize), @@ -35,9 +35,6 @@ _dl_make_stack_executable (void **stack_endp) ) != 0) return errno; - /* Clear the address. */ - *stack_endp = NULL; - /* Remember that we changed the permission. */ GL(dl_stack_flags) |= PF_X; |