[PATCH] this writing is a little easier to understand.

From: mudongliang
Date: Wed Nov 04 2015 - 09:47:47 EST


Signed-off-by: mudongliang <mudongliangabcd@xxxxxxxxx>
---
fs/binfmt_elf.c | 100 ++++++++++++++++++++++++++++----------------------------
1 file changed, 50 insertions(+), 50 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 6b65996..fbc450d 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -717,61 +717,61 @@ static int load_elf_binary(struct linux_binprm *bprm)
start_data = 0;
end_data = 0;

- for (i = 0; i < loc->elf_ex.e_phnum; i++) {
- if (elf_ppnt->p_type == PT_INTERP) {
- /* This is the program interpreter used for
- * shared libraries - for now assume that this
- * is an a.out format binary
- */
- retval = -ENOEXEC;
- if (elf_ppnt->p_filesz > PATH_MAX ||
- elf_ppnt->p_filesz < 2)
- goto out_free_ph;
-
- retval = -ENOMEM;
- elf_interpreter = kmalloc(elf_ppnt->p_filesz,
- GFP_KERNEL);
- if (!elf_interpreter)
- goto out_free_ph;
-
- retval = kernel_read(bprm->file, elf_ppnt->p_offset,
- elf_interpreter,
- elf_ppnt->p_filesz);
- if (retval != elf_ppnt->p_filesz) {
- if (retval >= 0)
- retval = -EIO;
- goto out_free_interp;
- }
- /* make sure path is NULL terminated */
- retval = -ENOEXEC;
- if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
- goto out_free_interp;
+ for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
+ if (elf_ppnt->p_type != PT_INTERP)
+ continue;

- interpreter = open_exec(elf_interpreter);
- retval = PTR_ERR(interpreter);
- if (IS_ERR(interpreter))
- goto out_free_interp;
+ /* This is the program interpreter used for
+ * shared libraries - for now assume that this
+ * is an a.out format binary
+ */
+ retval = -ENOEXEC;
+ if (elf_ppnt->p_filesz > PATH_MAX ||
+ elf_ppnt->p_filesz < 2)
+ goto out_free_ph;

- /*
- * If the binary is not readable then enforce
- * mm->dumpable = 0 regardless of the interpreter's
- * permissions.
- */
- would_dump(bprm, interpreter);
+ retval = -ENOMEM;
+ elf_interpreter = kmalloc(elf_ppnt->p_filesz,
+ GFP_KERNEL);
+ if (!elf_interpreter)
+ goto out_free_ph;
+
+ retval = kernel_read(bprm->file, elf_ppnt->p_offset,
+ elf_interpreter,
+ elf_ppnt->p_filesz);
+ if (retval != elf_ppnt->p_filesz) {
+ if (retval >= 0)
+ retval = -EIO;
+ goto out_free_interp;
+ }
+ /* make sure path is NULL terminated */
+ retval = -ENOEXEC;
+ if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
+ goto out_free_interp;

- retval = kernel_read(interpreter, 0, bprm->buf,
- BINPRM_BUF_SIZE);
- if (retval != BINPRM_BUF_SIZE) {
- if (retval >= 0)
- retval = -EIO;
- goto out_free_dentry;
- }
+ interpreter = open_exec(elf_interpreter);
+ retval = PTR_ERR(interpreter);
+ if (IS_ERR(interpreter))
+ goto out_free_interp;

- /* Get the exec headers */
- loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
- break;
+ /*
+ * If the binary is not readable then enforce
+ * mm->dumpable = 0 regardless of the interpreter's
+ * permissions.
+ */
+ would_dump(bprm, interpreter);
+
+ retval = kernel_read(interpreter, 0, bprm->buf,
+ BINPRM_BUF_SIZE);
+ if (retval != BINPRM_BUF_SIZE) {
+ if (retval >= 0)
+ retval = -EIO;
+ goto out_free_dentry;
}
- elf_ppnt++;
+
+ /* Get the exec headers */
+ loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
+ break;
}

elf_ppnt = elf_phdata;
--
2.1.4


--
My best regards to you.

No System Is Safe!
mudongliang
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