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Message-Id: <1327426472-25275-1-git-send-email-zohar@linux.vnet.ibm.com>
Date: Tue, 24 Jan 2012 12:34:32 -0500
From: Mimi Zohar <zohar@...ux.vnet.ibm.com>
To: linux-security-module@...r.kernel.org
Cc: Mimi Zohar <zohar@...ux.vnet.ibm.com>,
Al Viro <viro@...iv.linux.org.uk>,
Eric Paris <eparis@...hat.com>, linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org, Mimi Zohar <zohar@...ibm.com>
Subject: [PATCH v1] vfs: fix IMA lockdep circular locking dependency
The circular lockdep is caused by allocating the 'iint' for mmapped
files. Originally when an 'iint' was allocated for every inode
in inode_alloc_security(), before the inode was accessible, no
locking was necessary. Commits bc7d2a3e and 196f518 changed this
behavior and allocated the 'iint' on a per need basis, resulting in
the mmap_sem being taken before the i_mutex for mmapped files.
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&mm->mmap_sem);
lock(&sb->s_type->i_mutex_key);
lock(&mm->mmap_sem);
lock(&sb->s_type->i_mutex_key);
The existing security_file_mmap() hook is after the mmap_sem is taken.
This patch moves the ima_file_mmap() call from security_file_mmap() to
prior to the mmap_sem being taken.
Changelog v1:
- Instead of just pre-allocating the iint in a new hook, do ALL of the
work in the new/moved ima_file_mmap() hook. (Based on Eric Paris' suggestion.)
- Removed do_mmap_with_sem() helper function.
- export ima_file_mmap()
Signed-off-by: Mimi Zohar <zohar@...ibm.com>
---
arch/x86/ia32/ia32_aout.c | 12 ++++++++++++
fs/binfmt_aout.c | 12 ++++++++++++
fs/binfmt_elf.c | 10 ++++++++++
fs/binfmt_flat.c | 6 ++++++
fs/binfmt_som.c | 6 ++++++
mm/mmap.c | 6 ++++++
mm/nommu.c | 6 ++++++
security/integrity/ima/ima_main.c | 1 +
security/security.c | 7 +------
9 files changed, 60 insertions(+), 6 deletions(-)
diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index fd84387..7e44352 100644
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -25,6 +25,7 @@
#include <linux/personality.h>
#include <linux/init.h>
#include <linux/jiffies.h>
+#include <linux/ima.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -380,6 +381,13 @@ static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
goto beyond_if;
}
+ error = ima_file_mmap(bprm->file,
+ PROT_READ | PROT_WRITE | PROT_EXEC);
+ if (error < 0) {
+ send_sig(SIGKILL, current, 0);
+ return error;
+ }
+
down_write(¤t->mm->mmap_sem);
error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
PROT_READ | PROT_EXEC,
@@ -491,6 +499,10 @@ static int load_aout_library(struct file *file)
retval = 0;
goto out;
}
+ error = ima_file_mmap(file, PROT_READ | PROT_WRITE | PROT_EXEC);
+ if (error < 0)
+ goto out;
+
/* Now use mmap to map the library into memory. */
down_write(¤t->mm->mmap_sem);
error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index a6395bd..74cd792 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -25,6 +25,7 @@
#include <linux/init.h>
#include <linux/coredump.h>
#include <linux/slab.h>
+#include <linux/ima.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -320,6 +321,13 @@ static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
goto beyond_if;
}
+ error = ima_file_mmap(bprm->file,
+ PROT_READ | PROT_WRITE | PROT_EXEC);
+ if (error < 0) {
+ send_sig(SIGKILL, current, 0);
+ return error;
+ }
+
down_write(¤t->mm->mmap_sem);
error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
PROT_READ | PROT_EXEC,
@@ -426,6 +434,10 @@ static int load_aout_library(struct file *file)
retval = 0;
goto out;
}
+ retval = ima_file_mmap(file, PROT_READ | PROT_WRITE | PROT_EXEC);
+ if (retval < 0)
+ goto out;
+
/* Now use mmap to map the library into memory. */
down_write(¤t->mm->mmap_sem);
error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index bcb884e..26289d3 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -28,6 +28,7 @@
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/security.h>
+#include <linux/ima.h>
#include <linux/random.h>
#include <linux/elf.h>
#include <linux/utsname.h>
@@ -322,6 +323,7 @@ static unsigned long elf_map(struct file *filep, unsigned long addr,
unsigned long map_addr;
unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
+ unsigned long ret;
addr = ELF_PAGESTART(addr);
size = ELF_PAGEALIGN(size);
@@ -330,6 +332,10 @@ static unsigned long elf_map(struct file *filep, unsigned long addr,
if (!size)
return addr;
+ ret = ima_file_mmap(filep, prot);
+ if (ret < 0)
+ return ret;
+
down_write(¤t->mm->mmap_sem);
/*
* total_size is the size of the ELF (interpreter) image.
@@ -1050,6 +1056,10 @@ static int load_elf_library(struct file *file)
while (eppnt->p_type != PT_LOAD)
eppnt++;
+ error = ima_file_mmap(file, PROT_READ | PROT_WRITE | PROT_EXEC);
+ if (error < 0)
+ goto out_free_ph;
+
/* Now use mmap to map the library into memory. */
down_write(¤t->mm->mmap_sem);
error = do_mmap(file,
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 1bffbe0..b3b98d2 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -32,6 +32,7 @@
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/personality.h>
+#include <linux/ima.h>
#include <linux/init.h>
#include <linux/flat.h>
#include <linux/syscalls.h>
@@ -543,6 +544,11 @@ static int load_flat_file(struct linux_binprm * bprm,
*/
DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
+ ret = ima_file_mmap(bprm->file,
+ PROT_READ | PROT_WRITE | PROT_EXEC);
+ if (ret < 0)
+ goto err;
+
down_write(¤t->mm->mmap_sem);
textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_EXECUTABLE, 0);
diff --git a/fs/binfmt_som.c b/fs/binfmt_som.c
index cc8560f..47421f2 100644
--- a/fs/binfmt_som.c
+++ b/fs/binfmt_som.c
@@ -27,6 +27,7 @@
#include <linux/slab.h>
#include <linux/shm.h>
#include <linux/personality.h>
+#include <linux/ima.h>
#include <linux/init.h>
#include <asm/uaccess.h>
@@ -147,6 +148,11 @@ static int map_som_binary(struct file *file,
code_size = SOM_PAGEALIGN(hpuxhdr->exec_tsize);
current->mm->start_code = code_start;
current->mm->end_code = code_start + code_size;
+
+ retval = ima_file_mmap(file, prot);
+ if (retval < 0)
+ goto out;
+
down_write(¤t->mm->mmap_sem);
retval = do_mmap(file, code_start, code_size, prot,
flags, SOM_PAGESTART(hpuxhdr->exec_tfile));
diff --git a/mm/mmap.c b/mm/mmap.c
index 3f758c7..025e99b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -20,6 +20,7 @@
#include <linux/fs.h>
#include <linux/personality.h>
#include <linux/security.h>
+#include <linux/ima.h>
#include <linux/hugetlb.h>
#include <linux/profile.h>
#include <linux/export.h>
@@ -1108,10 +1109,15 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
+ retval = ima_file_mmap(file, prot);
+ if (retval < 0)
+ goto err_out;
+
down_write(¤t->mm->mmap_sem);
retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
up_write(¤t->mm->mmap_sem);
+err_out:
if (file)
fput(file);
out:
diff --git a/mm/nommu.c b/mm/nommu.c
index b982290..13b427d 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -27,6 +27,7 @@
#include <linux/mount.h>
#include <linux/personality.h>
#include <linux/security.h>
+#include <linux/ima.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
@@ -1486,10 +1487,15 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
+ retval = ima_file_mmap(file, prot);
+ if (retval < 0)
+ goto err_out;
+
down_write(¤t->mm->mmap_sem);
retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
up_write(¤t->mm->mmap_sem);
+err_out:
if (file)
fput(file);
out:
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 1eff5cb..5b222eb 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -176,6 +176,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)
MAY_EXEC, FILE_MMAP);
return 0;
}
+EXPORT_SYMBOL_GPL(ima_file_mmap);
/**
* ima_bprm_check - based on policy, collect/store measurement.
diff --git a/security/security.c b/security/security.c
index d754249..556c64c 100644
--- a/security/security.c
+++ b/security/security.c
@@ -673,12 +673,7 @@ int security_file_mmap(struct file *file, unsigned long reqprot,
unsigned long prot, unsigned long flags,
unsigned long addr, unsigned long addr_only)
{
- int ret;
-
- ret = security_ops->file_mmap(file, reqprot, prot, flags, addr, addr_only);
- if (ret)
- return ret;
- return ima_file_mmap(file, prot);
+ return security_ops->file_mmap(file, reqprot, prot, flags, addr, addr_only);
}
int security_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
--
1.7.6.5
--
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