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SubjectRe: [PATCH 2/3] binfmt_elf: Verify signature of signed elf binary
From
commit f6bf2c4c0339dabac435f518bb1fcb617fdef8f1
Author: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Date: Thu Jan 17 18:50:43 2013 +0200

ima: lock down memory if binary is digitally signed

This patch set a flag in the linux_binprm structure if binary is
digitally signed. The flag is used to lock down memory when loading
ELF binary.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 0c42cdb..ba94d13 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -44,6 +44,8 @@
#define user_siginfo_t siginfo_t
#endif

+#define LSM_UNSAFE_DIGSIG 16
+
static int load_elf_binary(struct linux_binprm *bprm);
static int load_elf_library(struct file *);
static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
@@ -788,6 +790,9 @@ static int load_elf_binary(struct linux_binprm *bprm)

elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;

+ if (bprm->unsafe & LSM_UNSAFE_DIGSIG)
+ elf_flags |= MAP_LOCKED;
+
vaddr = elf_ppnt->p_vaddr;
if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
elf_flags |= MAP_FIXED;
diff --git a/security/integrity/ima/ima_main.c
b/security/integrity/ima/ima_main.c
index b359fb5..50d9959 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -27,6 +27,8 @@

#include "ima.h"

+#define LSM_UNSAFE_DIGSIG 16
+
int ima_initialized;

#ifdef CONFIG_IMA_APPRAISE
@@ -315,10 +317,19 @@ int ima_file_mmap(struct file *file, unsigned long prot)
*/
int ima_bprm_check(struct linux_binprm *bprm)
{
- return process_measurement(bprm->file,
+ int err;
+ struct integrity_iint_cache *iint;
+
+ err = process_measurement(bprm->file,
(strcmp(bprm->filename, bprm->interp) == 0) ?
bprm->filename : bprm->interp,
MAY_EXEC, BPRM_CHECK);
+
+ iint = integrity_iint_find(bprm->file->f_dentry->d_inode);
+ if (iint && (iint->flags & IMA_DIGSIG))
+ bprm->unsafe |= LSM_UNSAFE_DIGSIG;
+
+ return err;
}

/**

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