[Patch 12/21] Check if the process is an ELF executable

From: Suzuki K. Poulose
Date: Tue Dec 14 2010 - 05:13:42 EST


Validate if the process is an ELF exec. This will be later extended to identify
if the task is a native ELF or a compat ELF.

Signed-off-by: Suzuki K. Poulose <suzuki@xxxxxxxxxx>
---
fs/proc/gencore.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

Index: linux-2.6.36-rc7/fs/proc/gencore.c
===================================================================
--- linux-2.6.36-rc7.orig/fs/proc/gencore.c
+++ linux-2.6.36-rc7/fs/proc/gencore.c
@@ -23,6 +23,8 @@
*/

#include <linux/seq_file.h>
+#include <linux/elf.h>
+
#include "internal.h"
#include "gencore.h"

@@ -85,6 +87,30 @@ static int release_gencore(struct inode
}

/*
+ * Determine whether the task is an ELF executable.
+ * Returns
+ * < 0 - Non-ELF
+ * 0 - Native ELF Executable
+ */
+static int get_elf_class(struct task_struct *task)
+{
+ struct elfhdr hdr;
+ int ret = 0;
+
+ ret = kernel_read(task->mm->exe_file, 0, (char*)&hdr, sizeof(hdr));
+ if (ret < 0)
+ return ret;
+
+ /* Verify the ELF magic on the exe_file */
+ if (memcmp(hdr.e_ident, ELFMAG, SELFMAG))
+ return -EINVAL;
+ if (elf_check_arch(&hdr))
+ return 0;
+
+ return -EINVAL;
+}
+
+/*
* Validate if the call is valid. We also need to prevent >1 open
* of the same file.
*/
@@ -93,10 +119,15 @@ static int open_gencore(struct inode *in
struct task_struct *task = get_proc_task(inode);
struct core_proc *cp;
int ret = 0;
+ int elf_class;

if (!task)
return -ENOENT;

+ elf_class = get_elf_class(task);
+ if (elf_class < 0)
+ return elf_class;
+
mutex_lock(&core_mutex);
cp = get_core_proc(task);
if (cp) {
--
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