From: Dave Martin <Dave.Martin@arm.com>
To: linux-kernel@vger.kernel.org
Cc: "Andrew Jones" <drjones@redhat.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Eugene Syromiatnikov" <esyr@redhat.com>,
"Florian Weimer" <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, "Jann Horn" <jannh@google.com>,
"Kees Cook" <keescook@chromium.org>,
"Kristina Martšenko" <kristina.martsenko@arm.com>,
"Marc Zyngier" <maz@kernel.org>,
"Mark Brown" <broonie@kernel.org>,
"Paul Elliott" <paul.elliott@arm.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Sudakshina Das" <sudi.das@arm.com>,
"Szabolcs Nagy" <szabolcs.nagy@arm.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Will Deacon" <will@kernel.org>,
"Yu-cheng Yu" <yu-cheng.yu@intel.com>,
"Amit Kachhap" <amit.kachhap@arm.com>,
"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 06/12] elf: Allow arch to tweak initial mmap prot flags
Date: Fri, 18 Oct 2019 18:25:39 +0100 [thread overview]
Message-ID: <1571419545-20401-7-git-send-email-Dave.Martin@arm.com> (raw)
In-Reply-To: <1571419545-20401-1-git-send-email-Dave.Martin@arm.com>
An arch may want to tweak the mmap prot flags for an
ELFexecutable's initial mappings. For example, arm64 is going to
need to add PROT_BTI for executable pages in an ELF process whose
executable is marked as using Branch Target Identification (an
ARMv8.5-A control flow integrity feature).
So that this can be done in a generic way, add a hook
arch_elf_adjust_prot() to modify the prot flags as desired: arches
can select CONFIG_HAVE_ELF_PROT and implement their own backend
where necessary.
By default, leave the prot flags unchanged.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
fs/Kconfig.binfmt | 3 +++
fs/binfmt_elf.c | 18 ++++++++++++------
include/linux/elf.h | 12 ++++++++++++
3 files changed, 27 insertions(+), 6 deletions(-)
diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index d2cfe07..2358368 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -36,6 +36,9 @@ config COMPAT_BINFMT_ELF
config ARCH_BINFMT_ELF_STATE
bool
+config ARCH_HAVE_ELF_PROT
+ bool
+
config ARCH_USE_GNU_PROPERTY
bool
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index ae345f6..dbfab2e 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -531,7 +531,8 @@ static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
#endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
-static inline int make_prot(u32 p_flags)
+static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state,
+ bool has_interp, bool is_interp)
{
int prot = 0;
@@ -541,7 +542,8 @@ static inline int make_prot(u32 p_flags)
prot |= PROT_WRITE;
if (p_flags & PF_X)
prot |= PROT_EXEC;
- return prot;
+
+ return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp);
}
/* This is much more generalized than the library routine read function,
@@ -551,7 +553,8 @@ static inline int make_prot(u32 p_flags)
static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
struct file *interpreter, unsigned long *interp_map_addr,
- unsigned long no_base, struct elf_phdr *interp_elf_phdata)
+ unsigned long no_base, struct elf_phdr *interp_elf_phdata,
+ struct arch_elf_state *arch_state)
{
struct elf_phdr *eppnt;
unsigned long load_addr = 0;
@@ -583,7 +586,8 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
if (eppnt->p_type == PT_LOAD) {
int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
- int elf_prot = make_prot(eppnt->p_flags);
+ int elf_prot = make_prot(eppnt->p_flags, arch_state,
+ true, true);
unsigned long vaddr = 0;
unsigned long k, map_addr;
@@ -1040,7 +1044,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
}
}
- elf_prot = make_prot(elf_ppnt->p_flags);
+ elf_prot = make_prot(elf_ppnt->p_flags, &arch_state,
+ !!interpreter, false);
elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
@@ -1186,7 +1191,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
elf_entry = load_elf_interp(&loc->interp_elf_ex,
interpreter,
&interp_map_addr,
- load_bias, interp_elf_phdata);
+ load_bias, interp_elf_phdata,
+ &arch_state);
if (!IS_ERR((void *)elf_entry)) {
/*
* load_elf_interp() returns relocation
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 7bdc6da..1b6e895 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -83,4 +83,16 @@ extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
bool compat, struct arch_elf_state *arch);
#endif
+#ifdef CONFIG_ARCH_HAVE_ELF_PROT
+int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
+ bool has_interp, bool is_interp);
+#else
+static inline int arch_elf_adjust_prot(int prot,
+ const struct arch_elf_state *state,
+ bool has_interp, bool is_interp)
+{
+ return prot;
+}
+#endif
+
#endif /* _LINUX_ELF_H */
--
2.1.4
next prev parent reply other threads:[~2019-10-18 17:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-18 17:25 [PATCH v3 00/12] arm64: ARMv8.5-A: Branch Target Identification support Dave Martin
2019-10-18 17:25 ` [PATCH v3 01/12] ELF: UAPI and Kconfig additions for ELF program properties Dave Martin
2019-10-29 23:07 ` Kees Cook
2019-10-18 17:25 ` [PATCH v3 02/12] ELF: Add ELF program property parsing support Dave Martin
2019-10-29 23:14 ` Kees Cook
2019-12-11 13:58 ` Mark Brown
2019-10-18 17:25 ` [PATCH v3 03/12] mm: Reserve asm-generic prot flag 0x10 for arch use Dave Martin
2019-10-18 17:25 ` [PATCH v3 04/12] arm64: docs: cpu-feature-registers: Document ID_AA64PFR1_EL1 Dave Martin
2019-10-18 17:25 ` [PATCH v3 05/12] arm64: Basic Branch Target Identification support Dave Martin
2019-10-18 17:25 ` Dave Martin [this message]
2019-10-29 23:19 ` [PATCH v3 06/12] elf: Allow arch to tweak initial mmap prot flags Kees Cook
2019-10-18 17:25 ` [PATCH v3 07/12] arm64: elf: Enable BTI at exec based on ELF program properties Dave Martin
2019-10-18 17:25 ` [PATCH v3 08/12] arm64: BTI: Decode BYTPE bits when printing PSTATE Dave Martin
2019-10-18 17:25 ` [PATCH v3 09/12] arm64: traps: Fix inconsistent faulting instruction skipping Dave Martin
2019-10-18 17:25 ` [PATCH v3 10/12] arm64: traps: Shuffle code to eliminate forward declarations Dave Martin
2019-10-18 17:25 ` [PATCH v3 11/12] arm64: BTI: Reset BTYPE when skipping emulated instructions Dave Martin
2019-10-18 17:25 ` [PATCH v3 12/12] KVM: " Dave Martin
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