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Commit cc338010 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
Browse files

fs/binfmt_elf.c: free PT_INTERP filename ASAP 

There is no reason for PT_INTERP filename to linger till the end of the
whole loading process.

Link: http://lkml.kernel.org/r/20190314204953.GD18143@avx2


Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarNikitas Angelinas <nikitas.angelinas@gmail.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Mukesh Ojha <mojha@codeaurora.org>
[nikitas.angelinas@gmail.com: fix GPF when dereferencing invalid interpreter]
  Link: http://lkml.kernel.org/r/20190330140032.GA1527@vostro


Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5cf4a363

fs/binfmt_elf.c

+11 −9
Original line number Diff line number Diff line
@@ -687,7 +687,6 @@ static int load_elf_binary(struct linux_binprm *bprm) 
	struct file *interpreter = NULL; /* to shut gcc up */

 	unsigned long load_addr = 0, load_bias = 0;

	int load_addr_set = 0;

	char * elf_interpreter = NULL;

	unsigned long error;

	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;

	unsigned long elf_bss, elf_brk;
@@ -743,6 +742,7 @@ static int load_elf_binary(struct linux_binprm *bprm) 


	for (i = 0; i < loc->elf_ex.e_phnum; i++) {

		if (elf_ppnt->p_type == PT_INTERP) {

			char *elf_interpreter;

			loff_t pos;



			/* This is the program interpreter used for
@@ -774,9 +774,10 @@ static int load_elf_binary(struct linux_binprm *bprm) 
				goto out_free_interp;



			interpreter = open_exec(elf_interpreter);

			kfree(elf_interpreter);

			retval = PTR_ERR(interpreter);

			if (IS_ERR(interpreter))

				goto out_free_interp;

				goto out_free_ph;



			/*

			 * If the binary is not readable then enforce
@@ -796,6 +797,10 @@ static int load_elf_binary(struct linux_binprm *bprm) 
			}



			break;



out_free_interp:

			kfree(elf_interpreter);

			goto out_free_ph;

		}

		elf_ppnt++;

	}
@@ -820,7 +825,7 @@ static int load_elf_binary(struct linux_binprm *bprm) 
		}



	/* Some simple consistency checks for the interpreter */

	if (elf_interpreter) {

	if (interpreter) {

		retval = -ELIBBAD;

		/* Not an ELF interpreter */

		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
@@ -977,7 +982,7 @@ static int load_elf_binary(struct linux_binprm *bprm) 
			 * independently randomized mmap region (0 load_bias

			 * without MAP_FIXED).

			 */

			if (elf_interpreter) {

			if (interpreter) {

				load_bias = ELF_ET_DYN_BASE;

				if (current->flags & PF_RANDOMIZE)

					load_bias += arch_mmap_rnd();
@@ -1075,7 +1080,7 @@ static int load_elf_binary(struct linux_binprm *bprm) 
		goto out_free_dentry;

	}



	if (elf_interpreter) {

	if (interpreter) {

		unsigned long interp_map_addr = 0;



		elf_entry = load_elf_interp(&loc->interp_elf_ex,
@@ -1099,7 +1104,6 @@ static int load_elf_binary(struct linux_binprm *bprm) 


		allow_write_access(interpreter);

		fput(interpreter);

		kfree(elf_interpreter);

	} else {

		elf_entry = loc->elf_ex.e_entry;

		if (BAD_ADDR(elf_entry)) {
@@ -1114,7 +1118,7 @@ static int load_elf_binary(struct linux_binprm *bprm) 
	set_binfmt(&elf_format);



#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES

	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);

	retval = arch_setup_additional_pages(bprm, !!interpreter);

	if (retval < 0)

		goto out;

#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
@@ -1175,8 +1179,6 @@ static int load_elf_binary(struct linux_binprm *bprm) 
	allow_write_access(interpreter);

	if (interpreter)

		fput(interpreter);

out_free_interp:

	kfree(elf_interpreter);

out_free_ph:

	kfree(elf_phdata);

	goto out;