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arm64: Enable BTI for the executable as well as the interpreter

PATCH Superseded Mark Brown 2 participants 9 messages Jul 12, 2021 – Jul 19, 2021

Subsystems (4)

v4 of 13 Superseded Latest is v13 →

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Mark Brown

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#0 lore raw

v4 cover arm64: Enable BTI for the executable as well as the interpreter

Deployments of BTI on arm64 have run into issues interacting with systemd's MemoryDenyWriteExecute feature. Currently for dynamically linked executables the kernel will only handle architecture specific properties like BTI for the interpreter, the expectation is that the interpreter will then handle any properties on the main executable. For BTI this means remapping the executable segments PROT_EXEC | PROT_BTI.

This interacts poorly with MemoryDenyWriteExecute since that is implemented using a seccomp filter which prevents setting PROT_EXEC on already mapped memory and lacks the context to be able to detect that memory is already mapped with PROT_EXEC. This series resolves this by handling the BTI property for both the interpreter and the main executable.

This does mean that we may get more code with BTI enabled if running on a system without BTI support in the dynamic linker, this is expected to be a safe configuration and testing seems to confirm that. It also reduces the flexibility userspace has to disable BTI but it is expected that for cases where there are problems which require BTI to be disabled it is more likely that it will need to be disabled on a system level.

v4:
- Rebase onto v5.14-rc1.
v3:
- Fix passing of properties for parsing by the main executable.
- Drop has_interp from arch_parse_elf_property().
- Coding style tweaks.
v2:
- Add a patch dropping has_interp from arch_adjust_elf_prot()
- Fix bisection issue with static executables on arm64 in the first patch.

Mark Brown (4):
elf: Allow architectures to parse properties on the main executable
arm64: Enable BTI for main executable as well as the interpreter
elf: Remove has_interp property from arch_adjust_elf_prot()
elf: Remove has_interp property from arch_parse_elf_property()

 arch/arm64/include/asm/elf.h | 13 ++++++++++---
 arch/arm64/kernel/process.c  | 23 +++++++++++------------
 fs/binfmt_elf.c              | 33 ++++++++++++++++++++++++---------
 include/linux/elf.h          |  8 +++++---
 4 files changed, 50 insertions(+), 27 deletions(-)

base-commit: e73f0f0ee7541171d89f2e2491130c7771ba58d3

Signature · 1 line
2.20.1
author
#1 lore raw

PATCH v4 1/4 elf: Allow architectures to parse properties on the main executable

Currently the ELF code only attempts to parse properties on the image that will start execution, either the interpreter or for statically linked executables the main executable. The expectation is that any property handling for the main executable will be done by the interpreter. This is a bit inconsistent since we do map the executable and is causing problems for the arm64 BTI support when used in conjunction with systemd's use of seccomp to implement MemoryDenyWriteExecute which stops the dynamic linker adjusting the permissions of executable segments.

Allow architectures to handle properties for both the dynamic linker and main executable, adjusting arch_parse_elf_properties() to have an is_interp flag as with arch_elf_adjust_prot() and calling it for both the main executable and any intepreter.

---
 arch/arm64/include/asm/elf.h |  3 ++-
 fs/binfmt_elf.c              | 31 +++++++++++++++++++++++--------
 include/linux/elf.h          |  4 +++-
 3 files changed, 28 insertions(+), 10 deletions(-)
arch/arm64/include/asm/elf.h +2 -1
index 8d1c8dcb87fd..a488a1329b16 100644
@@ -261,6 +261,7 @@ struct arch_elf_state {
 
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
+					  bool has_interp, bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	/* No known properties for AArch32 yet */
@@ -273,7 +274,7 @@ static inline int arch_parse_elf_property(u32 type, const void *data,
 		if (datasz != sizeof(*p))
 			return -ENOEXEC;
 
-		if (system_supports_bti() &&
+		if (system_supports_bti() && has_interp == is_interp &&
 		    (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
 			arch->flags |= ARM64_ELF_BTI;
 	}
fs/binfmt_elf.c +23 -8
index 439ed81e755a..81e151a57df2 100644
@@ -716,8 +716,9 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
  */
 
 static int parse_elf_property(const char *data, size_t *off, size_t datasz,
-			      struct arch_elf_state *arch,
-			      bool have_prev_type, u32 *prev_type)
+			      struct arch_elf_state *arch, bool has_interp,
+			      bool is_interp, bool have_prev_type,
+			      u32 *prev_type)
 {
 	size_t o, step;
 	const struct gnu_property *pr;
@@ -751,7 +752,8 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
 	*prev_type = pr->pr_type;
 
 	ret = arch_parse_elf_property(pr->pr_type, data + o,
-				      pr->pr_datasz, ELF_COMPAT, arch);
+				      pr->pr_datasz, ELF_COMPAT,
+				      has_interp, is_interp, arch);
 	if (ret)
 		return ret;
 
@@ -764,6 +766,7 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
 #define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME))
 
 static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
+				bool has_interp, bool is_interp,
 				struct arch_elf_state *arch)
 {
 	union {
@@ -813,7 +816,8 @@ static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
 	have_prev_type = false;
 	do {
 		ret = parse_elf_property(note.data, &off, datasz, arch,
-					 have_prev_type, &prev_type);
+					 has_interp, is_interp, have_prev_type,
+					 &prev_type);
 		have_prev_type = true;
 	} while (!ret);
 
@@ -828,6 +832,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	unsigned long error;
 	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
 	struct elf_phdr *elf_property_phdata = NULL;
+	struct elf_phdr *interp_elf_property_phdata = NULL;
 	unsigned long elf_bss, elf_brk;
 	int bss_prot = 0;
 	int retval, i;
@@ -936,6 +941,10 @@ static int load_elf_binary(struct linux_binprm *bprm)
 				executable_stack = EXSTACK_DISABLE_X;
 			break;
 
+		case PT_GNU_PROPERTY:
+			elf_property_phdata = elf_ppnt;
+			break;
+
 		case PT_LOPROC ... PT_HIPROC:
 			retval = arch_elf_pt_proc(elf_ex, elf_ppnt,
 						  bprm->file, false,
@@ -963,12 +972,11 @@ static int load_elf_binary(struct linux_binprm *bprm)
 			goto out_free_dentry;
 
 		/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
-		elf_property_phdata = NULL;
 		elf_ppnt = interp_elf_phdata;
 		for (i = 0; i < interp_elf_ex->e_phnum; i++, elf_ppnt++)
 			switch (elf_ppnt->p_type) {
 			case PT_GNU_PROPERTY:
-				elf_property_phdata = elf_ppnt;
+				interp_elf_property_phdata = elf_ppnt;
 				break;
 
 			case PT_LOPROC ... PT_HIPROC:
@@ -979,10 +987,17 @@ static int load_elf_binary(struct linux_binprm *bprm)
 					goto out_free_dentry;
 				break;
 			}
+
+		retval = parse_elf_properties(interpreter,
+					      interp_elf_property_phdata,
+					      true, true, &arch_state);
+		if (retval)
+			goto out_free_dentry;
+
 	}
 
-	retval = parse_elf_properties(interpreter ?: bprm->file,
-				      elf_property_phdata, &arch_state);
+	retval = parse_elf_properties(bprm->file, elf_property_phdata,
+				      interpreter != NULL, false, &arch_state);
 	if (retval)
 		goto out_free_dentry;
 
include/linux/elf.h +3 -1
index c9a46c4e183b..1c45ecf29147 100644
@@ -88,13 +88,15 @@ struct arch_elf_state;
 #ifndef CONFIG_ARCH_USE_GNU_PROPERTY
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
+					  bool has_interp, bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	return 0;
 }
 #else
 extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
-				   bool compat, struct arch_elf_state *arch);
+				   bool compat, bool has_interp, bool is_interp,
+				   struct arch_elf_state *arch);
 #endif
 
 #ifdef CONFIG_ARCH_HAVE_ELF_PROT
Signature · 1 line
2.20.1
Reviewed-by on v4 1/4
#2 lore raw

Re: [PATCH v4 1/4] elf: Allow architectures to parse properties on the main executable

Quoted 11 lines · Mark Brown

Currently the ELF code only attempts to parse properties on the image that will start execution, either the interpreter or for statically linked executables the main executable. The expectation is that any property handling for the main executable will be done by the interpreter. This is a bit inconsistent since we do map the executable and is causing problems for the arm64 BTI support when used in conjunction with systemd's use of seccomp to implement MemoryDenyWriteExecute which stops the dynamic linker adjusting the permissions of executable segments.

Allow architectures to handle properties for both the dynamic linker and main executable, adjusting arch_parse_elf_properties() to have an is_interp

Nit: to have has_interp and is_interp flags

Quoted 2 lines

flag as with arch_elf_adjust_prot() and calling it for both the main executable and any intepreter.

It would be helpful to note that the user of this code (arm64) is adapted to ensure that there is no functional change; otherwise the arm64 changes look a little non-obvious.

This is not a big deal though, and the code looks fine.

Quoted 2 lines

So, with or without the commit message tweaks:

Quoted 153 lines
---
 arch/arm64/include/asm/elf.h |  3 ++-
 fs/binfmt_elf.c              | 31 +++++++++++++++++++++++--------
 include/linux/elf.h          |  4 +++-
 3 files changed, 28 insertions(+), 10 deletions(-)
arch/arm64/include/asm/elf.h +2 -1
index 8d1c8dcb87fd..a488a1329b16 100644
@@ -261,6 +261,7 @@ struct arch_elf_state {
 
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
+					  bool has_interp, bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	/* No known properties for AArch32 yet */
@@ -273,7 +274,7 @@ static inline int arch_parse_elf_property(u32 type, const void *data,
 		if (datasz != sizeof(*p))
 			return -ENOEXEC;
 
-		if (system_supports_bti() &&
+		if (system_supports_bti() && has_interp == is_interp &&
 		    (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
 			arch->flags |= ARM64_ELF_BTI;
 	}
fs/binfmt_elf.c +23 -8
index 439ed81e755a..81e151a57df2 100644
@@ -716,8 +716,9 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
  */
 
 static int parse_elf_property(const char *data, size_t *off, size_t datasz,
-			      struct arch_elf_state *arch,
-			      bool have_prev_type, u32 *prev_type)
+			      struct arch_elf_state *arch, bool has_interp,
+			      bool is_interp, bool have_prev_type,
+			      u32 *prev_type)
 {
 	size_t o, step;
 	const struct gnu_property *pr;
@@ -751,7 +752,8 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
 	*prev_type = pr->pr_type;
 
 	ret = arch_parse_elf_property(pr->pr_type, data + o,
-				      pr->pr_datasz, ELF_COMPAT, arch);
+				      pr->pr_datasz, ELF_COMPAT,
+				      has_interp, is_interp, arch);
 	if (ret)
 		return ret;
 
@@ -764,6 +766,7 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
 #define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME))
 
 static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
+				bool has_interp, bool is_interp,
 				struct arch_elf_state *arch)
 {
 	union {
@@ -813,7 +816,8 @@ static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
 	have_prev_type = false;
 	do {
 		ret = parse_elf_property(note.data, &off, datasz, arch,
-					 have_prev_type, &prev_type);
+					 has_interp, is_interp, have_prev_type,
+					 &prev_type);
 		have_prev_type = true;
 	} while (!ret);
 
@@ -828,6 +832,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	unsigned long error;
 	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
 	struct elf_phdr *elf_property_phdata = NULL;
+	struct elf_phdr *interp_elf_property_phdata = NULL;
 	unsigned long elf_bss, elf_brk;
 	int bss_prot = 0;
 	int retval, i;
@@ -936,6 +941,10 @@ static int load_elf_binary(struct linux_binprm *bprm)
 				executable_stack = EXSTACK_DISABLE_X;
 			break;
 
+		case PT_GNU_PROPERTY:
+			elf_property_phdata = elf_ppnt;
+			break;
+
 		case PT_LOPROC ... PT_HIPROC:
 			retval = arch_elf_pt_proc(elf_ex, elf_ppnt,
 						  bprm->file, false,
@@ -963,12 +972,11 @@ static int load_elf_binary(struct linux_binprm *bprm)
 			goto out_free_dentry;
 
 		/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
-		elf_property_phdata = NULL;
 		elf_ppnt = interp_elf_phdata;
 		for (i = 0; i < interp_elf_ex->e_phnum; i++, elf_ppnt++)
 			switch (elf_ppnt->p_type) {
 			case PT_GNU_PROPERTY:
-				elf_property_phdata = elf_ppnt;
+				interp_elf_property_phdata = elf_ppnt;
 				break;
 
 			case PT_LOPROC ... PT_HIPROC:
@@ -979,10 +987,17 @@ static int load_elf_binary(struct linux_binprm *bprm)
 					goto out_free_dentry;
 				break;
 			}
+
+		retval = parse_elf_properties(interpreter,
+					      interp_elf_property_phdata,
+					      true, true, &arch_state);
+		if (retval)
+			goto out_free_dentry;
+
 	}
 
-	retval = parse_elf_properties(interpreter ?: bprm->file,
-				      elf_property_phdata, &arch_state);
+	retval = parse_elf_properties(bprm->file, elf_property_phdata,
+				      interpreter != NULL, false, &arch_state);
 	if (retval)
 		goto out_free_dentry;
 
include/linux/elf.h +3 -1
index c9a46c4e183b..1c45ecf29147 100644
@@ -88,13 +88,15 @@ struct arch_elf_state;
 #ifndef CONFIG_ARCH_USE_GNU_PROPERTY
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
+					  bool has_interp, bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	return 0;
 }
 #else
 extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
-				   bool compat, struct arch_elf_state *arch);
+				   bool compat, bool has_interp, bool is_interp,
+				   struct arch_elf_state *arch);
 #endif
 
 #ifdef CONFIG_ARCH_HAVE_ELF_PROT
Signature · 7 lines
2.20.1


_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
author
#3 lore raw

PATCH v4 2/4 arm64: Enable BTI for main executable as well as the interpreter

In reply to Mark Brown

Currently for dynamically linked ELF executables we only enable BTI for the interpreter, expecting the interpreter to do this for the main executable. This is a bit inconsistent since we do map main executable and is causing issues with systemd's MemoryDenyWriteExecute feature which is implemented using a seccomp filter which prevents setting PROT_EXEC on already mapped memory and lacks the context to be able to detect that memory is already mapped with PROT_EXEC.

Resolve this by checking the BTI property for the main executable and enabling BTI if it is present when doing the initial mapping. This does mean that we may get more code with BTI enabled if running on a system without BTI support in the dynamic linker, this is expected to be a safe configuration and testing seems to confirm that. It also reduces the flexibility userspace has to disable BTI but it is expected that for cases where there are problems which require BTI to be disabled it is more likely that it will need to be disabled on a system level.

---
 arch/arm64/include/asm/elf.h | 14 ++++++++++----
 arch/arm64/kernel/process.c  | 23 +++++++++++------------
 2 files changed, 21 insertions(+), 16 deletions(-)
arch/arm64/include/asm/elf.h +10 -4
index a488a1329b16..9f86dbce2680 100644
@@ -253,7 +253,8 @@ struct arch_elf_state {
 	int flags;
 };
 
-#define ARM64_ELF_BTI		(1 << 0)
+#define ARM64_ELF_INTERP_BTI		(1 << 0)
+#define ARM64_ELF_EXEC_BTI		(1 << 1)
 
 #define INIT_ARCH_ELF_STATE {			\
 	.flags = 0,				\
@@ -274,9 +275,14 @@ static inline int arch_parse_elf_property(u32 type, const void *data,
 		if (datasz != sizeof(*p))
 			return -ENOEXEC;
 
-		if (system_supports_bti() && has_interp == is_interp &&
-		    (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
-			arch->flags |= ARM64_ELF_BTI;
+		if (system_supports_bti() &&
+		    (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
+			if (is_interp) {
+				arch->flags |= ARM64_ELF_INTERP_BTI;
+			} else {
+				arch->flags |= ARM64_ELF_EXEC_BTI;
+			}
+		}
 	}
 
 	return 0;
arch/arm64/kernel/process.c +11 -12
index c8989b999250..5a6c3b198bd3 100644
@@ -683,21 +683,20 @@ core_initcall(tagged_addr_init);
 #endif	/* CONFIG_ARM64_TAGGED_ADDR_ABI */
 
 #ifdef CONFIG_BINFMT_ELF
-int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
-			 bool has_interp, bool is_interp)
+static inline int arm64_elf_bti_flag(bool is_interp)
 {
-	/*
-	 * For dynamically linked executables the interpreter is
-	 * responsible for setting PROT_BTI on everything except
-	 * itself.
-	 */
-	if (is_interp != has_interp)
-		return prot;
+	if (is_interp)
+		return ARM64_ELF_INTERP_BTI;
+	else
+		return ARM64_ELF_EXEC_BTI;
+}
 
-	if (!(state->flags & ARM64_ELF_BTI))
-		return prot;
 
-	if (prot & PROT_EXEC)
+int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
+			 bool has_interp, bool is_interp)
+{
+	if ((prot & PROT_EXEC) &&
+	    (state->flags & arm64_elf_bti_flag(is_interp)))
 		prot |= PROT_BTI;
 
 	return prot;
Signature · 1 line
2.20.1
Reviewed-by on v4 2/4
#4 lore raw

Re: [PATCH v4 2/4] arm64: Enable BTI for main executable as well as the interpreter

Quoted 43 lines · Mark Brown

Currently for dynamically linked ELF executables we only enable BTI for the interpreter, expecting the interpreter to do this for the main executable. This is a bit inconsistent since we do map main executable and is causing issues with systemd's MemoryDenyWriteExecute feature which is implemented using a seccomp filter which prevents setting PROT_EXEC on already mapped memory and lacks the context to be able to detect that memory is already mapped with PROT_EXEC.

Resolve this by checking the BTI property for the main executable and enabling BTI if it is present when doing the initial mapping. This does mean that we may get more code with BTI enabled if running on a system without BTI support in the dynamic linker, this is expected to be a safe configuration and testing seems to confirm that. It also reduces the flexibility userspace has to disable BTI but it is expected that for cases where there are problems which require BTI to be disabled it is more likely that it will need to be disabled on a system level.

---
 arch/arm64/include/asm/elf.h | 14 ++++++++++----
 arch/arm64/kernel/process.c  | 23 +++++++++++------------
 2 files changed, 21 insertions(+), 16 deletions(-)
arch/arm64/include/asm/elf.h +2 -1
index a488a1329b16..9f86dbce2680 100644
@@ -253,7 +253,8 @@ struct arch_elf_state {
 	int flags;
 };
 
-#define ARM64_ELF_BTI		(1 << 0)
+#define ARM64_ELF_INTERP_BTI		(1 << 0)
+#define ARM64_ELF_EXEC_BTI		(1 << 1)
 
 #define INIT_ARCH_ELF_STATE {			\
 	.flags = 0,				\
@@ -274,9 +275,14 @@ static inline int arch_parse_elf_property(u32 type, const void *data,
 		if (datasz != sizeof(*p))
 			return -ENOEXEC;
 

arch/arm64/include/asm/elf.h static inline int arch_parse_elf_property(u32 type, const void *data, · line 284

Quoted 10 lines
arch/arm64/include/asm/elf.h +7 -3
-		if (system_supports_bti() && has_interp == is_interp &&
-		    (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
-			arch->flags |= ARM64_ELF_BTI;
+		if (system_supports_bti() &&
+		    (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
+			if (is_interp) {
+				arch->flags |= ARM64_ELF_INTERP_BTI;
+			} else {
+				arch->flags |= ARM64_ELF_EXEC_BTI;
+			}

Can this just be

	arch->flags |= arm64_elf_bti_flag(is_interp);

if the helper is moved to this header?

Quoted 28 lines
arch/arm64/include/asm/elf.h +1 -0
+		}
 	}
 
 	return 0;
arch/arm64/kernel/process.c +6 -9
index c8989b999250..5a6c3b198bd3 100644
@@ -683,21 +683,20 @@ core_initcall(tagged_addr_init);
 #endif	/* CONFIG_ARM64_TAGGED_ADDR_ABI */
 
 #ifdef CONFIG_BINFMT_ELF
-int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
-			 bool has_interp, bool is_interp)
+static inline int arm64_elf_bti_flag(bool is_interp)
 {
-	/*
-	 * For dynamically linked executables the interpreter is
-	 * responsible for setting PROT_BTI on everything except
-	 * itself.
-	 */
-	if (is_interp != has_interp)
-		return prot;
+	if (is_interp)
+		return ARM64_ELF_INTERP_BTI;
+	else
+		return ARM64_ELF_EXEC_BTI;
+}

arch/arm64/kernel/process.c core_initcall(tagged_addr_init); · line 699

Quoted 10 lines
arch/arm64/kernel/process.c +5 -3
 
-	if (!(state->flags & ARM64_ELF_BTI))
-		return prot;
 
-	if (prot & PROT_EXEC)
+int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
+			 bool has_interp, bool is_interp)
+{
+	if ((prot & PROT_EXEC) &&
+	    (state->flags & arm64_elf_bti_flag(is_interp)))

Preferably with the above change (but if not, I'll live without):

Quoted 4 lines
arch/arm64/kernel/process.c +0 -0
 		prot |= PROT_BTI;
 
 	return prot;
author
#5 lore raw

PATCH v4 3/4 elf: Remove has_interp property from arch_adjust_elf_prot()

In reply to Mark Brown

Since we have added an is_interp flag to arch_parse_elf_property() we can drop the has_interp flag from arch_elf_adjust_prot(), the only user was the arm64 code which no longer needs it and any future users will be able to use arch_parse_elf_properties() to determine if an interpreter is in use.

---
 arch/arm64/kernel/process.c | 2 +-
 fs/binfmt_elf.c             | 2 +-
 include/linux/elf.h         | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)
arch/arm64/kernel/process.c +1 -1
index 5a6c3b198bd3..992d827b37b0 100644
@@ -693,7 +693,7 @@ static inline int arm64_elf_bti_flag(bool is_interp)
 
 
 int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
-			 bool has_interp, bool is_interp)
+			 bool is_interp)
 {
 	if ((prot & PROT_EXEC) &&
 	    (state->flags & arm64_elf_bti_flag(is_interp)))
fs/binfmt_elf.c +1 -1
index 81e151a57df2..ae8094d42480 100644
@@ -580,7 +580,7 @@ static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state,
 	if (p_flags & PF_X)
 		prot |= PROT_EXEC;
 
-	return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp);
+	return arch_elf_adjust_prot(prot, arch_state, is_interp);
 }
 
 /* This is much more generalized than the library routine read function,
include/linux/elf.h +2 -2
index 1c45ecf29147..d8392531899d 100644
@@ -101,11 +101,11 @@ extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
 
 #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);
+			 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)
+				       bool is_interp)
 {
 	return prot;
 }
Signature · 1 line
2.20.1
Reviewed-by on v4 3/4
#6 lore raw

Re: [PATCH v4 3/4] elf: Remove has_interp property from arch_adjust_elf_prot()

Quoted 5 lines · Mark Brown

Since we have added an is_interp flag to arch_parse_elf_property() we can drop the has_interp flag from arch_elf_adjust_prot(), the only user was the arm64 code which no longer needs it and any future users will be able to use arch_parse_elf_properties() to determine if an interpreter is in use.

Quoted 61 lines
---
 arch/arm64/kernel/process.c | 2 +-
 fs/binfmt_elf.c             | 2 +-
 include/linux/elf.h         | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)
arch/arm64/kernel/process.c +1 -1
index 5a6c3b198bd3..992d827b37b0 100644
@@ -693,7 +693,7 @@ static inline int arm64_elf_bti_flag(bool is_interp)
 
 
 int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
-			 bool has_interp, bool is_interp)
+			 bool is_interp)
 {
 	if ((prot & PROT_EXEC) &&
 	    (state->flags & arm64_elf_bti_flag(is_interp)))
fs/binfmt_elf.c +1 -1
index 81e151a57df2..ae8094d42480 100644
@@ -580,7 +580,7 @@ static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state,
 	if (p_flags & PF_X)
 		prot |= PROT_EXEC;
 
-	return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp);
+	return arch_elf_adjust_prot(prot, arch_state, is_interp);
 }
 
 /* This is much more generalized than the library routine read function,
include/linux/elf.h +2 -2
index 1c45ecf29147..d8392531899d 100644
@@ -101,11 +101,11 @@ extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
 
 #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);
+			 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)
+				       bool is_interp)
 {
 	return prot;
 }
Signature · 7 lines
2.20.1


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author
#7 lore raw

PATCH v4 4/4 elf: Remove has_interp property from arch_parse_elf_property()

In reply to Mark Brown

Since all current users of arch_parse_elf_property() are able to treat the interpreter and main executable orthogonaly the has_interp argument is now redundant so remove it.

---
 arch/arm64/include/asm/elf.h | 2 +-
 fs/binfmt_elf.c              | 2 +-
 include/linux/elf.h          | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)
arch/arm64/include/asm/elf.h +1 -1
index 9f86dbce2680..a6e9032b951a 100644
@@ -262,7 +262,7 @@ struct arch_elf_state {
 
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
-					  bool has_interp, bool is_interp,
+					  bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	/* No known properties for AArch32 yet */
fs/binfmt_elf.c +1 -1
index ae8094d42480..f0b3c24215f6 100644
@@ -753,7 +753,7 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
 
 	ret = arch_parse_elf_property(pr->pr_type, data + o,
 				      pr->pr_datasz, ELF_COMPAT,
-				      has_interp, is_interp, arch);
+				      is_interp, arch);
 	if (ret)
 		return ret;
 
include/linux/elf.h +2 -2
index d8392531899d..cdb080d4b34a 100644
@@ -88,14 +88,14 @@ struct arch_elf_state;
 #ifndef CONFIG_ARCH_USE_GNU_PROPERTY
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
-					  bool has_interp, bool is_interp,
+					  bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	return 0;
 }
 #else
 extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
-				   bool compat, bool has_interp, bool is_interp,
+				   bool compat, bool is_interp,
 				   struct arch_elf_state *arch);
 #endif
 
Signature · 1 line
2.20.1
Reviewed-by on v4 4/4
#8 lore raw

Re: [PATCH v4 4/4] elf: Remove has_interp property from arch_parse_elf_property()

Quoted 3 lines · Mark Brown

Since all current users of arch_parse_elf_property() are able to treat the interpreter and main executable orthogonaly the has_interp argument is now redundant so remove it.

Quoted 64 lines
---
 arch/arm64/include/asm/elf.h | 2 +-
 fs/binfmt_elf.c              | 2 +-
 include/linux/elf.h          | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)
arch/arm64/include/asm/elf.h +1 -1
index 9f86dbce2680..a6e9032b951a 100644
@@ -262,7 +262,7 @@ struct arch_elf_state {
 
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
-					  bool has_interp, bool is_interp,
+					  bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	/* No known properties for AArch32 yet */
fs/binfmt_elf.c +1 -1
index ae8094d42480..f0b3c24215f6 100644
@@ -753,7 +753,7 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
 
 	ret = arch_parse_elf_property(pr->pr_type, data + o,
 				      pr->pr_datasz, ELF_COMPAT,
-				      has_interp, is_interp, arch);
+				      is_interp, arch);
 	if (ret)
 		return ret;
 
include/linux/elf.h +2 -2
index d8392531899d..cdb080d4b34a 100644
@@ -88,14 +88,14 @@ struct arch_elf_state;
 #ifndef CONFIG_ARCH_USE_GNU_PROPERTY
 static inline int arch_parse_elf_property(u32 type, const void *data,
 					  size_t datasz, bool compat,
-					  bool has_interp, bool is_interp,
+					  bool is_interp,
 					  struct arch_elf_state *arch)
 {
 	return 0;
 }
 #else
 extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
-				   bool compat, bool has_interp, bool is_interp,
+				   bool compat, bool is_interp,
 				   struct arch_elf_state *arch);
 #endif
 
Signature · 7 lines
2.20.1


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