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From: Paul Burton <paul.burton@imgtec.com>
To: <linux-mips@linux-mips.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	Paul Burton <paul.burton@imgtec.com>
Subject: [PATCH 02/10] binfmt_elf: load interpreter program headers earlier
Date: Thu, 11 Sep 2014 08:30:15 +0100	[thread overview]
Message-ID: <1410420623-11691-3-git-send-email-paul.burton@imgtec.com> (raw)
In-Reply-To: <1410420623-11691-1-git-send-email-paul.burton@imgtec.com>

Load the program headers of an ELF interpreter early enough in
load_elf_binary that they can be examined before it's too late to return
an error from an exec syscall. This patch does not perform any such
checking, it merely lays the groundwork for a further patch to do so.

No functional change is intended.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
---
 fs/binfmt_elf.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 64ca110..61dabe0 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -447,9 +447,8 @@ out:
 
 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 		struct file *interpreter, unsigned long *interp_map_addr,
-		unsigned long no_base)
+		unsigned long no_base, struct elf_phdr *interp_elf_phdata)
 {
-	struct elf_phdr *elf_phdata;
 	struct elf_phdr *eppnt;
 	unsigned long load_addr = 0;
 	int load_addr_set = 0;
@@ -467,17 +466,14 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 	if (!interpreter->f_op->mmap)
 		goto out;
 
-	elf_phdata = load_elf_phdrs(interp_elf_ex, interpreter);
-	if (!elf_phdata)
-		goto out;
-
-	total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum);
+	total_size = total_mapping_size(interp_elf_phdata,
+					interp_elf_ex->e_phnum);
 	if (!total_size) {
 		error = -EINVAL;
-		goto out_close;
+		goto out;
 	}
 
-	eppnt = elf_phdata;
+	eppnt = interp_elf_phdata;
 	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
 		if (eppnt->p_type == PT_LOAD) {
 			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
@@ -504,7 +500,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 				*interp_map_addr = map_addr;
 			error = map_addr;
 			if (BAD_ADDR(map_addr))
-				goto out_close;
+				goto out;
 
 			if (!load_addr_set &&
 			    interp_elf_ex->e_type == ET_DYN) {
@@ -523,7 +519,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 			    eppnt->p_memsz > TASK_SIZE ||
 			    TASK_SIZE - eppnt->p_memsz < k) {
 				error = -ENOMEM;
-				goto out_close;
+				goto out;
 			}
 
 			/*
@@ -553,7 +549,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 		 */
 		if (padzero(elf_bss)) {
 			error = -EFAULT;
-			goto out_close;
+			goto out;
 		}
 
 		/* What we have mapped so far */
@@ -562,13 +558,10 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 		/* Map the last of the bss segment */
 		error = vm_brk(elf_bss, last_bss - elf_bss);
 		if (BAD_ADDR(error))
-			goto out_close;
+			goto out;
 	}
 
 	error = load_addr;
-
-out_close:
-	kfree(elf_phdata);
 out:
 	return error;
 }
@@ -605,7 +598,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	int load_addr_set = 0;
 	char * elf_interpreter = NULL;
 	unsigned long error;
-	struct elf_phdr *elf_ppnt, *elf_phdata;
+	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
 	unsigned long elf_bss, elf_brk;
 	int retval, i;
 	unsigned long elf_entry;
@@ -729,6 +722,12 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		/* Verify the interpreter has a valid arch */
 		if (!elf_check_arch(&loc->interp_elf_ex))
 			goto out_free_dentry;
+
+		/* Load the interpreter program headers */
+		interp_elf_phdata = load_elf_phdrs(&loc->interp_elf_ex,
+						   interpreter);
+		if (!interp_elf_phdata)
+			goto out_free_dentry;
 	}
 
 	/* Flush all traces of the currently running executable */
@@ -912,7 +911,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		elf_entry = load_elf_interp(&loc->interp_elf_ex,
 					    interpreter,
 					    &interp_map_addr,
-					    load_bias);
+					    load_bias, interp_elf_phdata);
 		if (!IS_ERR((void *)elf_entry)) {
 			/*
 			 * load_elf_interp() returns relocation
@@ -1009,6 +1008,7 @@ out_ret:
 
 	/* error cleanup */
 out_free_dentry:
+	kfree(interp_elf_phdata);
 	allow_write_access(interpreter);
 	if (interpreter)
 		fput(interpreter);
-- 
2.0.4


WARNING: multiple messages have this Message-ID (diff)
From: Paul Burton <paul.burton@imgtec.com>
To: linux-mips@linux-mips.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paul Burton <paul.burton@imgtec.com>
Subject: [PATCH 02/10] binfmt_elf: load interpreter program headers earlier
Date: Thu, 11 Sep 2014 08:30:15 +0100	[thread overview]
Message-ID: <1410420623-11691-3-git-send-email-paul.burton@imgtec.com> (raw)
Message-ID: <20140911073015.lHg6PDOKD_jOeEIp8u40JgnY2wYmknIi7OK0uXeFvIQ@z> (raw)
In-Reply-To: <1410420623-11691-1-git-send-email-paul.burton@imgtec.com>

Load the program headers of an ELF interpreter early enough in
load_elf_binary that they can be examined before it's too late to return
an error from an exec syscall. This patch does not perform any such
checking, it merely lays the groundwork for a further patch to do so.

No functional change is intended.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
---
 fs/binfmt_elf.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 64ca110..61dabe0 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -447,9 +447,8 @@ out:
 
 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 		struct file *interpreter, unsigned long *interp_map_addr,
-		unsigned long no_base)
+		unsigned long no_base, struct elf_phdr *interp_elf_phdata)
 {
-	struct elf_phdr *elf_phdata;
 	struct elf_phdr *eppnt;
 	unsigned long load_addr = 0;
 	int load_addr_set = 0;
@@ -467,17 +466,14 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 	if (!interpreter->f_op->mmap)
 		goto out;
 
-	elf_phdata = load_elf_phdrs(interp_elf_ex, interpreter);
-	if (!elf_phdata)
-		goto out;
-
-	total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum);
+	total_size = total_mapping_size(interp_elf_phdata,
+					interp_elf_ex->e_phnum);
 	if (!total_size) {
 		error = -EINVAL;
-		goto out_close;
+		goto out;
 	}
 
-	eppnt = elf_phdata;
+	eppnt = interp_elf_phdata;
 	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
 		if (eppnt->p_type == PT_LOAD) {
 			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
@@ -504,7 +500,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 				*interp_map_addr = map_addr;
 			error = map_addr;
 			if (BAD_ADDR(map_addr))
-				goto out_close;
+				goto out;
 
 			if (!load_addr_set &&
 			    interp_elf_ex->e_type == ET_DYN) {
@@ -523,7 +519,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 			    eppnt->p_memsz > TASK_SIZE ||
 			    TASK_SIZE - eppnt->p_memsz < k) {
 				error = -ENOMEM;
-				goto out_close;
+				goto out;
 			}
 
 			/*
@@ -553,7 +549,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 		 */
 		if (padzero(elf_bss)) {
 			error = -EFAULT;
-			goto out_close;
+			goto out;
 		}
 
 		/* What we have mapped so far */
@@ -562,13 +558,10 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 		/* Map the last of the bss segment */
 		error = vm_brk(elf_bss, last_bss - elf_bss);
 		if (BAD_ADDR(error))
-			goto out_close;
+			goto out;
 	}
 
 	error = load_addr;
-
-out_close:
-	kfree(elf_phdata);
 out:
 	return error;
 }
@@ -605,7 +598,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	int load_addr_set = 0;
 	char * elf_interpreter = NULL;
 	unsigned long error;
-	struct elf_phdr *elf_ppnt, *elf_phdata;
+	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
 	unsigned long elf_bss, elf_brk;
 	int retval, i;
 	unsigned long elf_entry;
@@ -729,6 +722,12 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		/* Verify the interpreter has a valid arch */
 		if (!elf_check_arch(&loc->interp_elf_ex))
 			goto out_free_dentry;
+
+		/* Load the interpreter program headers */
+		interp_elf_phdata = load_elf_phdrs(&loc->interp_elf_ex,
+						   interpreter);
+		if (!interp_elf_phdata)
+			goto out_free_dentry;
 	}
 
 	/* Flush all traces of the currently running executable */
@@ -912,7 +911,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		elf_entry = load_elf_interp(&loc->interp_elf_ex,
 					    interpreter,
 					    &interp_map_addr,
-					    load_bias);
+					    load_bias, interp_elf_phdata);
 		if (!IS_ERR((void *)elf_entry)) {
 			/*
 			 * load_elf_interp() returns relocation
@@ -1009,6 +1008,7 @@ out_ret:
 
 	/* error cleanup */
 out_free_dentry:
+	kfree(interp_elf_phdata);
 	allow_write_access(interpreter);
 	if (interpreter)
 		fput(interpreter);
-- 
2.0.4

  parent reply	other threads:[~2014-09-11  8:42 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-11  7:30 [PATCH 00/10] MIPS O32 new FP ABI support Paul Burton
2014-09-11  7:30 ` Paul Burton
2014-09-11  7:30 ` [PATCH 01/10] binfmt_elf: hoist ELF program header loading to a function Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-09-11  7:30 ` Paul Burton [this message]
2014-09-11  7:30   ` [PATCH 02/10] binfmt_elf: load interpreter program headers earlier Paul Burton
2014-11-13 12:20   ` Thierry Reding
2014-11-13 17:29     ` Ralf Baechle
2014-09-11  7:30 ` [PATCH 03/10] binfmt_elf: allow arch code to examine PT_LOPROC ... PT_HIPROC headers Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-11-12 13:41   ` Thierry Reding
2014-11-13  0:16     ` Ralf Baechle
2014-11-13 12:25       ` Thierry Reding
2014-09-11  7:30 ` [PATCH 04/10] MIPS: define bits introduced for hybrid FPRs Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-09-11  7:30 ` [PATCH 05/10] MIPS: detect presence of the FRE & UFR bits Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-09-11  7:30 ` [PATCH 06/10] MIPS: ensure Config5.UFE is clear on boot Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-09-11  7:30 ` [PATCH 07/10] MIPS: support for hybrid FPRs Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-12-23 23:21   ` Aaro Koskinen
2014-12-23 23:31     ` James Hogan
2014-12-23 23:31       ` James Hogan
2014-12-23 23:51       ` Aaro Koskinen
2014-09-11  7:30 ` [PATCH 08/10] MIPS: ELF: add definition for the .MIPS.abiflags section Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-09-11  7:30 ` [PATCH 09/10] MIPS: ELF: set FP mode according to .MIPS.abiflags Paul Burton
2014-09-11  7:30   ` Paul Burton
2014-09-11  7:30 ` [PATCH 10/10] MIPS: Kconfig option to better exercise/debug hybrid FPRs Paul Burton
2014-09-11  7:30   ` Paul Burton

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