From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>, libc-alpha@sourceware.org
Cc: Mark Rutland <mark.rutland@arm.com>,
kernel-hardening@lists.openwall.com,
Catalin Marinas <catalin.marinas@arm.com>,
linux-kernel@vger.kernel.org,
Jeremy Linton <jeremy.linton@arm.com>,
Mark Brown <broonie@kernel.org>,
Topi Miettinen <toiwoton@gmail.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/6] aarch64: Fix missing BTI protection from dependencies [BZ #26926]
Date: Thu, 10 Dec 2020 14:51:23 -0300 [thread overview]
Message-ID: <f077a6d5-082c-c3a5-ce07-71b87a70dc12@linaro.org> (raw)
In-Reply-To: <8756cc1083eb4cd93d3766cd39b2f34b6623bbcb.1606319495.git.szabolcs.nagy@arm.com>
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.
> ---
> 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.
next prev parent reply other threads:[~2020-12-10 17:52 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 13:19 [PATCH v2 0/6] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) [BZ #26831] Szabolcs Nagy
2020-11-27 13:19 ` [PATCH v2 1/6] aarch64: Fix missing BTI protection from dependencies [BZ #26926] Szabolcs Nagy
2020-12-10 17:51 ` Adhemerval Zanella [this message]
2020-12-11 15:33 ` Szabolcs Nagy
2020-11-27 13:20 ` [PATCH v2 2/6] elf: lose is closely tied to _dl_map_object_from_fd Szabolcs Nagy
2020-11-27 13:20 ` [PATCH v2 3/6] elf: Fix failure handling in _dl_map_object_from_fd Szabolcs Nagy
2020-12-10 18:25 ` Adhemerval Zanella
2020-12-11 9:32 ` Szabolcs Nagy
2020-11-27 13:20 ` [PATCH v2 4/6] elf: Move note processing after l_phdr is updated Szabolcs Nagy
2020-11-27 13:21 ` [PATCH v2 5/6] elf: Pass the fd to note processing Szabolcs Nagy
2020-12-10 18:35 ` Adhemerval Zanella
2020-11-27 13:21 ` [PATCH v2 6/6] aarch64: Use mmap to add PROT_BTI instead of mprotect [BZ #26831] Szabolcs Nagy
2020-12-02 8:55 ` [PATCH v3 1/2] aarch64: align address for BTI protection [BZ #26988] Szabolcs Nagy
2020-12-10 18:49 ` Adhemerval Zanella
2020-12-02 8:55 ` [PATCH v3 2/2] aarch64: Use mmap to add PROT_BTI instead of mprotect [BZ #26831] Szabolcs Nagy
2020-12-10 19:12 ` Adhemerval Zanella
2020-11-30 15:56 ` [PATCH v2 0/6] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) " Szabolcs Nagy
2020-12-03 17:30 ` Catalin Marinas
2020-12-07 20:03 ` Szabolcs Nagy
2020-12-11 17:46 ` Catalin Marinas
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