Re: [PATCH v2 1/6] aarch64: Fix missing BTI protection from dependencies [BZ #26926]
From: Adhemerval Zanella <hidden>
Date: 2020-12-10 17:52:17
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lkml
On 27/11/2020 10:19, Szabolcs Nagy via Libc-alpha wrote:
The _dl_open_check and _rtld_main_check hooks are not called on the dependencies of a loaded module, so BTI protection was missed on every module other than the main executable and directly dlopened libraries. The fix just iterates over dependencies to enable BTI. Fixes bug 26926.
LGTM, modulus the argument name change. I also think it would be better to add a testcase, for both DT_NEEDED and dlopen case.
quoted hunk ↗ jump to hunk
--- sysdeps/aarch64/dl-bti.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)diff --git a/sysdeps/aarch64/dl-bti.c b/sysdeps/aarch64/dl-bti.c index 196e462520..8f4728adce 100644 --- a/sysdeps/aarch64/dl-bti.c +++ b/sysdeps/aarch64/dl-bti.c@@ -51,11 +51,24 @@ enable_bti (struct link_map *map, const char *program) return 0; } -/* Enable BTI for L if required. */ +/* Enable BTI for MAP and its dependencies. */ void -_dl_bti_check (struct link_map *l, const char *program) +_dl_bti_check (struct link_map *map, const char *program)
I don't see much gain changing the argument name.
{
- if (GLRO(dl_aarch64_cpu_features).bti && l->l_mach.bti)
- enable_bti (l, program);
+ if (!GLRO(dl_aarch64_cpu_features).bti)
+ return;
+
+ if (map->l_mach.bti)
+ enable_bti (map, program);
+
+ unsigned int i = map->l_searchlist.r_nlist;
+ while (i-- > 0)
+ {
+ struct link_map *l = map->l_initfini[i];
+ if (l->l_init_called)
+ continue;
+ if (l->l_mach.bti)
+ enable_bti (l, program);
+ }
}Ok. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel