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author | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2015-12-30 15:35:30 +0300 |
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committer | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2016-02-21 17:06:12 +0300 |
commit | a1db74209483a24c861c848b4bb79a4d945ef6fa (patch) | |
tree | 4edf4c1a22e4a8446166366e5cee358c99e8fda0 /kernel | |
parent | b844f0ecbc5626ec26cfc70cb144a4c9b85dc3f2 (diff) | |
download | linux-a1db74209483a24c861c848b4bb79a4d945ef6fa.tar.xz |
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')
-rw-r--r-- | kernel/module.c | 68 |
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); } |