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Commit 8454aeef authored by Eugene Teo's avatar Eugene Teo Committed by Linus Torvalds
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[PATCH] Require mmap handler for a.out executables 



Files supported by fs/proc/base.c, i.e.  /proc/<pid>/*, are not capable of
meeting the validity checks in ELF load_elf_*() handling because they have
no mmap handler which is required by ELF.  In order to stop a.out
executables being used as part of an exploit attack against /proc-related
vulnerabilities, we make a.out executables depend on ->mmap() existing.

Signed-off-by: default avatarEugene Teo <eteo@redhat.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 563d0757

fs/binfmt_aout.c

+14 −0
Original line number Diff line number Diff line
@@ -278,6 +278,13 @@ static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs) 
		return -ENOEXEC;

	}



	/*

	 * Requires a mmap handler. This prevents people from using a.out

	 * as part of an exploit attack against /proc-related vulnerabilities.

	 */

	if (!bprm->file->f_op || !bprm->file->f_op->mmap)

		return -ENOEXEC;



	fd_offset = N_TXTOFF(ex);



	/* Check initial limits. This avoids letting people circumvent
@@ -476,6 +483,13 @@ static int load_aout_library(struct file *file) 
		goto out;

	}



	/*

	 * Requires a mmap handler. This prevents people from using a.out

	 * as part of an exploit attack against /proc-related vulnerabilities.

	 */

	if (!file->f_op || !file->f_op->mmap)

		goto out;



	if (N_FLAGS(ex))

		goto out;