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authorMimi Zohar <zohar@linux.vnet.ibm.com>2015-12-30 07:35:30 -0500
committerMimi Zohar <zohar@linux.vnet.ibm.com>2016-02-21 09:06:12 -0500
commita1db74209483a24c861c848b4bb79a4d945ef6fa (patch)
tree4edf4c1a22e4a8446166366e5cee358c99e8fda0 /kernel/module.c
parentb844f0ecbc5626ec26cfc70cb144a4c9b85dc3f2 (diff)
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module: replace copy_module_from_fd with kernel version
Replace copy_module_from_fd() with kernel_read_file_from_fd(). Although none of the upstreamed LSMs define a kernel_module_from_file hook, IMA is called, based on policy, to prevent unsigned kernel modules from being loaded by the original kernel module syscall and to measure/appraise signed kernel modules. The security function security_kernel_module_from_file() was called prior to reading a kernel module. Preventing unsigned kernel modules from being loaded by the original kernel module syscall remains on the pre-read kernel_read_file() security hook. Instead of reading the kernel module twice, once for measuring/appraising and again for loading the kernel module, the signature validation is moved to the kernel_post_read_file() security hook. This patch removes the security_kernel_module_from_file() hook and security call. Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c68
1 files changed, 8 insertions, 60 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 8358f4697c0c..955410928696 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2654,7 +2654,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
if (info->len < sizeof(*(info->hdr)))
return -ENOEXEC;
- err = security_kernel_module_from_file(NULL);
+ err = security_kernel_read_file(NULL, READING_MODULE);
if (err)
return err;
@@ -2672,63 +2672,6 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
return 0;
}
-/* Sets info->hdr and info->len. */
-static int copy_module_from_fd(int fd, struct load_info *info)
-{
- struct fd f = fdget(fd);
- int err;
- struct kstat stat;
- loff_t pos;
- ssize_t bytes = 0;
-
- if (!f.file)
- return -ENOEXEC;
-
- err = security_kernel_module_from_file(f.file);
- if (err)
- goto out;
-
- err = vfs_getattr(&f.file->f_path, &stat);
- if (err)
- goto out;
-
- if (stat.size > INT_MAX) {
- err = -EFBIG;
- goto out;
- }
-
- /* Don't hand 0 to vmalloc, it whines. */
- if (stat.size == 0) {
- err = -EINVAL;
- goto out;
- }
-
- info->hdr = vmalloc(stat.size);
- if (!info->hdr) {
- err = -ENOMEM;
- goto out;
- }
-
- pos = 0;
- while (pos < stat.size) {
- bytes = kernel_read(f.file, pos, (char *)(info->hdr) + pos,
- stat.size - pos);
- if (bytes < 0) {
- vfree(info->hdr);
- err = bytes;
- goto out;
- }
- if (bytes == 0)
- break;
- pos += bytes;
- }
- info->len = pos;
-
-out:
- fdput(f);
- return err;
-}
-
static void free_copy(struct load_info *info)
{
vfree(info->hdr);
@@ -3589,8 +3532,10 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
{
- int err;
struct load_info info = { };
+ loff_t size;
+ void *hdr;
+ int err;
err = may_init_module();
if (err)
@@ -3602,9 +3547,12 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
|MODULE_INIT_IGNORE_VERMAGIC))
return -EINVAL;
- err = copy_module_from_fd(fd, &info);
+ err = kernel_read_file_from_fd(fd, &hdr, &size, INT_MAX,
+ READING_MODULE);
if (err)
return err;
+ info.hdr = hdr;
+ info.len = size;
return load_module(&info, uargs, flags);
}